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Background/Objectives: Antibodies against the hepatitis B surface antigen (anti-HBs) are a marker of immunity against hepatitis B virus (HBV) infections. There is uncertainty about the anti-HBs seroprevalence in the general population of Austria. Methods: We conducted a cross-sectional analysis in blood donors from the Federal State of Tyrol in Austria (August–September 2023) to estimate anti-HBs seroprevalence and median antibody levels. Results: We enrolled 3935 blood donors (median age 47.6 years [25th–75th percentile: 33.3–56.6]; 40.7% female), who were hepatitis B surface antigen negative and had no detectable HBV-DNA. Overall seroprevalence was 51.4% (95% CI: 49.8–52.9%). Anti-HBs seropositivity decreased with higher age (p < 0.001), with 70.3% (66.1–74.3%) being seropositive among participants < 25 years of age and 30.2% (24.2–36.9%) in those aged ≥ 65 years. More females than males were seropositive (54.3% [51.8–56.7%] vs. 49.4% [47.4–51.4%]; p = 0.003). Seroprevalence was significantly higher in urban than in rural areas in participants aged 40 to <55 (p = 0.045) and ≥55 years (p = 0.001). Among 2022 seropositive participants, the overall median anti-HBs antibody level was 539.3 IU/L (25th–75th percentile: 116.3–5417.0). Furthermore, 5% of the participants had an anti-HBs antibody level between 10 and <20 IU/L, 18% between 20 and <100 IU/L, and 77% ≥100 IU/L. Conclusions: Anti-HBs seroprevalence in blood donors from Tyrol, Austria, was 51.4% between August and September 2023 and differed across age, sex, and residence area. Catch-up vaccination programs, especially targeting the elderly living in rural areas, are needed to close HBV immunity gaps. [ABSTRACT FROM AUTHOR]

Background: The Co-FriSero study describes a COVID-19 outbreak at the Friedrichroda hospital in Thuringia, Germany, with 185 beds and 404 employees, at the onset of the pandemic between March 30th, 2020, and April 13th, 2020. This study aimed to analyze potential sources of SARS-CoV-2 transmission amongst hospital employees. Methods: After the outbreak, a comprehensive follow-up was conducted through a questionnaire and a seroprevalence study using two different immunoassays for IgG detection and a third for discordant results. Results: PCR screenings confirmed SARS-CoV-2 infection in 25 of 229 employees, with an additional 7 detected through serology. Statistical analysis indicated that direct patient contact, exposure to high flow ventilation in non-isolated rooms, direct contact with colleagues, shared use of recreational rooms, and carpooling were associated with an increased infection risk. Conversely, contact with family and friends, public transportation, public events, and use of locker rooms were not associated with infection. Male gender showed a lower infection likelihood, independent of age and other risk factors. Conclusion: This study highlights the role of direct patient care and internal staff interactions in the spread of SARS-CoV-2 in the hospital setting. It suggests that non-traditional transmission routes like carpooling require consideration in pandemic preparedness. [ABSTRACT FROM AUTHOR]

Leptospirosis is a worldwide zoonotic disease caused by pathogenic Leptospira spp., often occurring in tropical and subtropical regions. Focusing on development of rapid diagnostic methods to facilitate early diagnosis and a universal vaccine are the main critical issues to overcome the burden of leptospirosis. Here, we have studied the immunogenic potential of prepared recombinant Loa22 protein (rLoa22) of local pathogenic Leptospira species in mice and its ability to induce humoral and cellular immunity, being further evaluated by analyzing the immunoglobulin G (IgG) subclasses and cytokines produced through immunization. Based on the results, mice immunized with rLoa22/adjuvant and a trivalent vaccine, induced high titers of total IgG. All immunized groups increased IgG1 almost on the same level; but, IgG2a level was significantly higher in the vaccine and rLoa22/adjuvant groups than rLoa22 alone group. Animals immunized with the vaccine produced more interleukin 4 than rLoa22/adjuvant group. The results of evaluating interferon gamma level showed that the rLoa22/adjuvant and vaccine groups had a significant increase compared to the rLoa22 alone group. The results also demonstrated that the rLoa22 protein, in indirect enzyme-linked immunosorbent assay, was able to detect the anti-Leptospira antibodies in mice serum that can be used as a marker in assessing the seroprevalence of leptospirosis and/or in combination with other leptospiral antigens in development of an effective vaccine against leptospirosis. [ABSTRACT FROM AUTHOR]

The hepatitis E virus (HEV) is an emerging infectious disease with zoonotic potential, causing acute hepatitis in humans. Infections in healthy individuals are often acute, self-limiting and asymptomatic, thus leading to the underdiagnosis of HEV infections. Asymptomatic HEV infections pose a problem for blood transfusion safety by increasing the risk for transfusion-transmitted HEV infections. Here, we describe the journey from determining the HEV seroprevalence among blood donors to the implementation of routine HEV RNA testing of all blood products in Switzerland in 2018 and summarise the HEV cases detected since. In total, 290 HEV-positive blood donations were detected by mini-pool nucleic acid testing (NAT) in Switzerland in the period of October 2018–December 2023, equal to an incidence of 20.7 per 100,000 donations. Thanks to the implemented scheme, no transfusion-transmitted infections occurred in this period. Furthermore, blood donation monitoring has proven to be an effective means of detecting HEV outbreaks in the general population. HEV cases in Swiss blood donors are caused by two major genotypes, the Swiss-endemic subtypes 3h3 and 3c. Interestingly, 11 HEV cases (5%) were of genotype 3ra, a variant found in wild and farmed rabbits. Our results indicate that mini-pool NAT is an efficient method to reduce the risk of transfusion-transmitted HEV infections. [ABSTRACT FROM AUTHOR]

Background: SARS-CoV-2, the causative agent of COVID-19, is a betacoronavirus belonging to the same genus as endemic human coronaviruses (hCoVs) OC43 and HKU1 and is distinct from alpha hCoVs 229E and NL63. In a study of adolescents in the Philippines, we evaluated seroprevalence to the hCoVs, whether pre-pandemic hCoV immunity modulated subsequent risk of SARS-CoV-2 infection, and if SARS-CoV-2 infection affected the transmission of the hCoVs. Methods: From 499 individuals screened in 2021 for SARS-CoV-2 receptor binding domain (RBD) antibodies by enzyme-linked immunosorbent assay (ELISA), we randomly selected 59 SARS-CoV-2 negative and 61 positive individuals for further serological evaluation. We measured RBD and spike antibodies to the four hCoVs and SARS-CoV-2 by ELISA in samples from the same participants collected pre-pandemic (2018–2019) and mid-pandemic (2021), before COVID-19 vaccination. Results: We observed over 72% seropositivity to the four hCoVs pre-pandemic. Binding antibodies increased with age to 229E and OC43, suggesting endemic circulation, while antibody levels was flat across ages for HKU1 and NL63. During the COVID-19 pandemic, antibodies increased significantly to the RBDs of OC43, NL63, and 229E and spikes of all four hCoVs in both SARS-CoV-2 negative and positive adolescents. Those aged 12–15 years old in 2021 had higher antibodies to RBD and spike of OC43, NL63, and 229E than adolescents the same age in 2019, further demonstrating intense transmission of the hCoVs during the pandemic. Conclusions: We observe a limited impact of the COVID-19 pandemic on endemic hCoV transmission. This study provides insight into co-circulation of hCoVs and SARS-CoV-2. [ABSTRACT FROM AUTHOR]

To effectively respond to an emerging infectious disease outbreak, policymakers need timely and accurate measures of disease prevalence in the general population. This paper presents a new methodology to estimate real-time population infection rates from non-random testing data. The approach compares how the observed positivity rate varies with the size of the tested population and applies this gradient to infer total population infections. Applying this methodology to daily testing data across U.S. states during the first wave of the COVID-19 pandemic, we estimated widespread undiagnosed COVID-19 infections. Nationwide, we found that for every identified case, there were 12 population infections. Our prevalence estimates align with results from seroprevalence surveys, alternate approaches to measuring COVID-19 infections, and total excess mortality during the first wave of the pandemic. [ABSTRACT FROM AUTHOR]

Emerging infectious diseases are a major threat to biodiversity and an important public health issue. Flaviviruses are the cause of several emerging vector-borne zoonotic arboviruses whose distribution is currently increasing in Europe. The evidence that West Nile virus (WNV) circulates in resident and migratory species has implications for both animal and public health and should therefore be studied in depth. USUTU (USUV), Bagaza (BAGV) and tick-borne encephalitis virus (TBEV) are other viruses that are beginning to spread more widely. An integrated surveillance program, namely in birds, is essential for reducing the risk of infection in human populations within the One Health principles. In the present study, wild birds admitted to wildlife rehabilitation centers in Portugal were sampled. Two hundred eight blood samples were assayed serologically for antibodies to flaviviruses by using a commercial ELISA kit. An overall seroprevalence of 19.6% (95% confidence interval [CI]: 13.7–26.7%) was observed. Antibodies against flaviviruses were detected in 13 (35.1%) different species of wild birds. Accipitriformes (26.7%; 95% CI: 18.5–36.2%) and Strigiformes (26.7%; 95% CI: 14.6–42.0%) were the orders with the highest seroprevalence rates recorded. There were no statistically significant differences (p = 0.725) between the geographical regions (NUTS II) studied, but a statistically significant difference (p = 0.017) was found between sex (male: 34.4%; female: 4.8%). A higher seroprevalence was detected in adults (32.1%) than in juvenile birds (9.3%) (p = 0.014), and age was considered a risk factor for flavivirus infection in wild birds (odds ratio 1.4; 95% CI: 0.5–4.0). More epidemiological studies are needed in Portugal since the actual spread of the genus Flavivirus throughout the country is unknown. [ABSTRACT FROM AUTHOR]

Introduction: Hantavirus infection is a zoonotic disease from rodents to humans, necessitating seroprevalence assessment for disease burden clarification and control measure implementation. This study aimed to estimate global hantaviruses seroprevalence, examining variations by regions, populations or settings. Methods: A comprehensive database search identified studies on human hantaviruses seroprevalence using IgG detection until january 2024. A random-effects meta-analysis estimated pooled seroprevalence, with subgroup analyses for geographical region, population, setting or occupation. Results: Out of 3,382 abstracts reviewed, 110 studies were selected, comprising 81,815 observations and 3207 events. The global seroprevalence was calculated at 2.93% (2.34%-3.67%). In terms of geographical distribution, our analysis encompassed 61 studies from the Americas, where the seroprevalence was estimated at 2.43% (95% CI: 1.71%—3.46%), 33 studies from Europe indicating a seroprevalence of 2.98% (95% CI: 2.19%—4.06%), 10 studies from Asia revealing a seroprevalence of 6.84% (95% CI: 3.64%—12.50%), and 6 studies from Africa demonstrating a seroprevalence of 2.21% (95% CI: 1.82%—2.71%). Subgroup analysis underscored varying seroprevalence rates across different populations, settings, and occupations, highlighting the necessity for targeted interventions and preventive measures. Conclusion: The analysis reveals a moderate global hantaviruses seroprevalence, emphasizing the viral family's complex transmission dynamics influenced by exposure and geographical factors. This highlights the need for targeted prevention and control strategies. [ABSTRACT FROM AUTHOR]

Background: Following reduction of public health and social measures concurrent with SARS-CoV-2 Omicron emergence in late 2021 in Australia, COVID-19 case notification rates rose rapidly. As rates of direct viral testing and reporting dropped, true infection rates were most likely to be underestimated. Objective: To better understand infection rates and immunity in this population, we aimed to estimate SARS-CoV-2 seroprevalence in Australians aged 0–19 years. Methods: We conducted a national cross sectional serosurvey from June 1, 2022, to August 31, 2022, in children aged 0–19 years undergoing an anesthetic procedure at eight tertiary pediatric hospitals. Participant questionnaires were administered, and blood samples tested using the Roche Elecsys Anti-SARS-CoV-2 total spike and nucleocapsid antibody assays. Spike and nucleocapsid seroprevalence adjusted for geographic and socioeconomic imbalances in the participant sample compared to the Australian population was estimated using multilevel regression and poststratification within a Bayesian framework. Results: Blood was collected from 2,046 participants (median age: 6.6 years). The overall adjusted seroprevalence of spike-antibody was 92.1% (95% credible interval (CrI) 91.0–93.3%) and nucleocapsid-antibody was 67.0% (95% CrI 64.6–69.3). In unvaccinated children spike and nucleocapsid antibody seroprevalences were 84.2% (95% CrI 81.9–86.5) and 67.1% (95%CrI 64.0–69.8), respectively. Seroprevalence was similar across geographic remoteness index and socioeconomic quintiles. Nucleocapsid antibody seroprevalence increased with age while the point seroprevalence of the spike antibody seroprevalence decreased in the first year of life and then increased to 97.8 (95% Crl 96.1–99.2) by 12–15 years of age. Conclusion: Most Australian children and adolescents aged 0–19 years, across all jurisdictions were infected with SARS-CoV-2 by August 2022, suggesting rapid and uniform spread across the population in a very short time period. High seropositivity in unvaccinated children informed COVID-19 vaccine recommendations in Australia. [ABSTRACT FROM AUTHOR]

Hepatitis C is a serious public health issue because of its chronic nature and potential to progress to cirrhosis and liver cancer, particularly among haemodialysis patients. This systematic review and meta-analysis aimed to estimate the combined prevalence of hepatitis C in these patients in Morocco. After selecting 17 studies out of 943 identified, the data were analysed using the JAMOVI software, with a random-effects model to estimate the prevalence. The overall prevalence of hepatitis C among haemodialysis patients in Morocco was estimated at 35.8% (95% CI: 26.3 to 45.3). These findings highlight the urgent need for research on the factors contributing to the spread of this infection in this population. [ABSTRACT FROM AUTHOR]

Background: Hepatitis A virus (HAV) infection is a significant global cause of viral hepatitis. At present, the anti-HAV vaccine in Italy is proposed exclusively for specific high-risk groups, and a universal vaccination program is not implemented. Objectives: This study aimed to assess the level of immunity against HAV in patients of both sexes across age groups ranging from 0 to 95 years admitted to the San Giovanni di Dio e Ruggi d'Aragona Hospital in Salerno, Italy, over a 9-year period (2015–2023). Methods: The total HAV seroprevalence by chemiluminescence Vitros system immunodiagnostics (ortho-diagnostics) was obtained by database analysis, stratifying patients for gender and age group in both the pre-pandemic (2015–2019) and pandemic (2020–2023) periods. Results: Out of 28,104 samples collected in 2015–2023, 20,613 resulted positive by total HAV immune screening, with a significant reduction in the annualized proportion of events during the pandemic period compared to the pre-pandemic period. HAV was more abundant in males than females in both periods (exceeding the 70%), with a statistically significant decrease in HAV in females in 2015–2019. The 61–70-year-old age group is more susceptible for both genders, with a strong deviation from the 41–50-year-old age group compared to the 51–60-year-old group. The pandemic period affected the number of analyzed samples in 2020. Conclusions: The study revealed high HAV seroprevalence, especially in males and individuals aged 61–70 years. There was a notable decrease in seroprevalence during the pandemic compared to pre-pandemic years. These results emphasize the need for ongoing monitoring and suggest that a universal vaccination program could address regional immunity gaps and lower disease incidence. [ABSTRACT FROM AUTHOR]

Background and Aims Methods Results Conclusions Although the evidence is uncertain, existing estimates for hepatitis C virus (HCV) in sub‐Saharan Africa (SSA) indicate a high burden. We estimated HCV seroprevalence and viraemic prevalence among the general population in SSA.We searched Medline, Embase, Web of Science, APA PsycINFO, and World Health Organization Africa Index Medicus for community‐based studies. Study quality was assessed using the Joanna Briggs Institute critical appraisal tool, and heterogeneity using the index of heterogeneity (I2). Two approaches were deployed. First, we used random‐effects meta‐analysis to pool prevalence. Second, to derive representative estimates, we weighted each country's HCV seroprevalence using 2021 United Nations country population sizes.We synthesized 130 studies. Overall, SSA HCV seroprevalence from the random‐effects model was 4.17% (95% confidence interval [CI]: 3.71–4.66, I2 = 99.30%). There were no differences between males (4.31%) and females (4.03%). Seroprevalence was 2.25%, 3.31%, and 16.23% for ages ≤20, 21–64, and ≥65 years, respectively, and was higher in rural (6.63%) versus urban (2.93%). There was indication of decrement overtime from 5.74% to 4.35% to 3.03% in the years 1984–2000, 2001–2014, and 2015–2023, respectively. The weighted overall SSA HCV seroprevalence was estimated to be 2.30% (95% CI: 1.59–3.00) with regional variation: Africa‐Southern (.79%), Africa‐Central (1.47%), Africa‐Eastern (2.71%), and Africa‐Western (2.88%). HCV viremia among HCV seropositives was 54.77% (95% CI: 47.80–61.66).HCV seroprevalence in SSA remains high. Populations aged ≥65 years, rural communities, Africa‐Western, and some countries in Africa‐Central and Africa‐Eastern appear disproportionately affected. These results underline the need for governmental commitment to achieve the 2030 global HCV elimination targets. [ABSTRACT FROM AUTHOR]

Background: Schistosomiasis is a global public health issue. In China, while the seroprevalence of Schistosomiasis japonica has currently reduced to a relatively low level, risk of infection still exists in certain areas. However, there has been a lack of comprehensive research on the long-term trends of national seroprevalence, changes across age groups, and characteristics in spatial distribution, which is crucial for effectively targeting interventions and achieving the goal of eliminating schistosomiasis by 2030. Our study aimed to address this gap by analyzing the long-term trends of Schistosomiasis japonica seroprevalence in China from 1982 to 2020 based on the data from diverse sources spanning a period of 39 years. Methodology: Seroprevalence data were collected from literature databases and national schistosomiasis surveillance system. Meta-analysis was conducted to estimate the seroprevalence. Joinpoint model was used to identify changing trend and inflection point. Inverse distance weighted interpolation was used to determine the spatial distribution of seroprevalence. Principal findings: The seroprevalence decreased from 34.8% in 1982 to 2.4% in 2020 in China. Before 2006, the seroprevalence was higher in the middle age group, and a pattern of increasing with age was observed afterwards. The areas with high seroprevalence existed in Dongting Lake, Poyang Lake, Jianghan Plain, the Anhui branch of the Yangtze River and some localized mountainous regions in Sichuan and Yunnan provinces. Conclusions/Significance: There was a significant decline in the seroprevalence of Schistosomiasis japonica from 1982 to 2020 in China. Nevertheless, schistosomiasis has not been eradicated; thus, implementing precise and personalized monitoring measures is crucial for the elimination of schistosomiasis, especially in endemic areas and with a particular focus on the elderly. Author summary: Serological immunological testing is a crucial means of monitoring schistosomiasis. In China, while the seroprevalence of Schistosomiasis japonica has currently reduced to a relatively low level, risk of infection still exists in certain areas. Achieving the goal of eliminating schistosomiasis by 2030 necessitates more precise and effective prevention and control measures. Our study intended to figure out the long-term trends of Schistosomiasis japonica seroprevalence in China from 1982 to 2020, focusing on age and spatial variations to identify high-risk areas and populations. We expect that the results can inform the development of targeted measures for schistosomiasis elimination. [ABSTRACT FROM AUTHOR]

Background: The current survey describes the seroprevalence, history of coronavirus disease 2019 (COVID-19), and vaccination status among predominantly aboriginal residents on a tourist island in southern Thailand. This information can be translated into COVID-19 vaccination and control plans for this population. Methods: We implemented questionnaire interviews and collected blood samples from 249 residents of Lipe Island, Satun Province, in January 2022. We measured the anti-nucleocapsid protein and anti-spike (anti-S) receptor-binding protein levels of immunoglobulin (Ig) M and IgG. The differences in antibody levels among participants with different histories of vaccination and infection were analyzed using one-way analysis of variance with multiple comparisons. Results: During the 2-year pandemic period, no island residents with COVID-19 required hospitalization despite the high prevalence of hypertension (33.3%) and diabetes mellitus (21.7%). Approximately 18.8% of the participants reported a history of COVID-19 diagnosis. In total, 95.1% of the participants had a history of complete vaccination, of which 93.5% were seropositive. The anti-S IgG geometric means (geometric standard deviation) were 3945.8 (2.0), 829.8 (9.7) AU/mL, 789.9 (5.3) AU/mL, and 22.7 (7.1) AU/mL, respectively, in participants with a history of both COVID-19 diagnosis and complete vaccination (group 1), incomplete vaccination and subsequent COVID-19 diagnosis (group 2), complete vaccination but no previous infection (group 3), or neither previous COVID-19 and complete vaccination (group 4). Significant pairwise differences in anti-S IgG levels were found between certain groups (1 vs 3, 1 vs 4, 2 vs 4, and 3 vs 4). Conclusions: The high coverage of vaccination, high levels of population antibody titers, variable antibody levels among completely vaccinated non-infected residents, and high prevalence of non-communicable diseases (NCDs) suggested that the local health systems could control the pandemic. However, continuing surveillance, booster vaccinations, and NCD prevention programs were still required. [ABSTRACT FROM AUTHOR]

Objective: Crimean‐Congo haemorrhagic fever (CCHF) is a severe zoonotic arboviral disease that occurs widely in Eastern and Western Europe, Asia and Africa. The disease is becoming of growing public health importance in Senegal. However, analysis of tick infestation, CCHF virus (CCHFV) circulation extent and risk factors during ongoing outbreak are scarce. A thorough outbreak investigation was carried out during a CCHF outbreak in Podor (Northern Senegal) in August 2022. Methods: Ticks and blood samples were collected from animals (cattle, goats and sheep) randomly selected from confirmed CCHF human cases houses, neighbourhoods and surrounding villages. Blood samples were tested for CCHFV antibodies using a commercial enzyme‐linked immunosorbent assay (ELISA) test. Tick samples were screened for CCHFV RNA by RT‐PCR. Results: Overall, tick infestation rate (TIR) and CCHFV seroprevalence of livestock were 52.12% (95% confidence interval (CI): 45.54%–58.64%) and 43.28% (95% CI: 36.33%–50.44%), respectively. The TIRs were 87.7% in cattle, 57.6% in sheep and 20.0% in goats. These rates were significantly associated with location, host species and tick control (p < 0.001) but not with animal age and sex (p > 0.7). CCHFV seroprevalence was 80.4% (95% CI: 67.57%–89.77%) in cattle, 35.4% (95% CI: 25.00%–47.01%) in sheep and 21.2% (95% CI: 12.11%–33.02%) in goats. Age, sex, location, animal host and presence of ticks were significantly associated to the presence of antibodies. The 950 ticks collected included among other species, Hyalomma impeltatum (48.84%) and H. rufipes (10.21%). Five pools of Hyalomma ssp. were found CCHFV RT‐PCR positive. These infected ticks included 0.86% (4/464) of H. impeltatum collected on cattle and sheep and 1.03% (1/97) of H. rufipes collected on a sheep. Conclusions: To our knowledge, this is the first report on the extend of tick infestation and CCHFV infection in livestock during an outbreak in Senegal. The results highlight the risk of human infections and the importance of strengthening vector, animal and human surveillance as well as tick control measures in this area to prevent CCHF infections in humans. [ABSTRACT FROM AUTHOR]

Introduction: Updated data on the seroprevalences of hepatitis B and C viruses (HBV, HCV) are required to enable the adaptation of control strategies. In this study, we aimed to: (i) estimate the seroprevalences of HBsAg carriers and HCV exposure in the general population, and (ii) determine the impact of vaccination on HBV circulation since its introduction in 2006 in the Expanded Program on Immunization (EPI). Methodology: From October 2020 to October 2022, a mass screening campaign was conducted in 10 cities across Burkina Faso. Individuals of all ages and genders who consented to participate were screened for viral markers (HBsAg, anti-HCV) using rapid diagnostic tests. The proportions of HBsAg carriers and HCV exposure were calculated using Stata, and logistic regression was used to assess the impact of HBV vaccination on HBsAg carriage. Results: A total of 15,650 participants were enrolled in the study. Of these, 51.4% were women and the age range was from 1 to 97 years. All participants were screened for HBsAg and 7,507 were also screened for anti-HCV. Overall, the seroprevalence of HBsAg was 8.8% and 2.6% for anti-HCV. The results indicated that age, gender, and place of residence were associated with HBV infection. Conclusions: The prevalence of HBV and HCV infections remains high in Burkina Faso. Prevention strategies, including initial mass screening with rapid diagnostic tests and vaccination, need to be intensified. [ABSTRACT FROM AUTHOR]

(1) Background: early in the COVID-19 pandemic, reverse transcription polymerase chain reaction (RT-PCR) testing was limited. Assessing seroprevalence helps understand prevalence and reinfection risk. However, such data are lacking for the first epidemic wave in Belgian nursing homes. Therefore, we assessed SARS-CoV-2 seroprevalence and cumulative RT-PCR positivity in Belgian nursing homes and evaluated reinfection risk. (2) Methods: we performed a cross-sectional study in nine nursing homes in April and May 2020. Odds ratios (ORs) were calculated to compare the odds of (re)infection between seropositive and seronegative participants. (3) Results: seroprevalence was 21% (95% CI: 18–23): 22% (95% CI: 18–25) in residents and 20% (95% CI: 17–24) in staff. By 20 May 2020, cumulative RT-PCR positivity was 16% (95% CI: 13–21) in residents and 8% (95% CI: 6–12) in staff. ORs for (re)infection in seropositive (compared to seronegative) residents and staff were 0.22 (95% CI: 0.06–0.72) and 3.15 (95% CI: 1.56–6.63), respectively. (4) Conclusion: during the first wave, RT-PCR test programmes underestimated the number of COVID-19 cases. The reinfection rate in residents was 3%, indicating protection, while it was 21% in staff, potentially due to less cautious health behaviour. Future outbreaks should use both RT-PCR and serological testing for complementary insights into transmission dynamics. [ABSTRACT FROM AUTHOR]

Hepatitis C virus (HCV) infection is among the leading causes of cirrhosis and hepatocellular carcinoma. Knowledge of its prevalence and risk factors can help to effectively fight the virus. This study was the first to investigate the seroprevalence of HCV, its genotypes, and factors associated with it among the general adult population of Armenia selected countrywide via cluster sampling. Anti-HCV antibodies were detected using third-generation immunoassay. Polymerase chain reaction and genotyping was performed among anti-HCV-positive individuals. Shortly after testing, the participants underwent a telephone survey. Logistic regression models were fitted to identify factors associated with anti-HCV antibody positivity and chronic HCV infection. The prevalence of anti-HCV antibodies among 3831 tested individuals was 2% (99% CI 1.4, 2.5), and chronic HCV infection was 0.7% (99% CI 0.4, 1.0), with genotypes 3 and 2 being the most common. The risk factors for chronic HCV infection included self-reported chronic liver disease (95% CI 1.47, 15.28), having tattoos (95% CI 1.34, 10.94), ever smoking (95% CI 1.16, 9.18), and testing positive for hepatitis B virus core antibody (95% CI 1.02, 7.17). These risk factors demonstrate that there could be room for strengthening infection control measures to prevent the transmission of HCV in Armenia. [ABSTRACT FROM AUTHOR]

Background: Seroprevalence studies have proven to be an important tool in tracking the progression of the coronavirus disease 2019 (COVID‐19) pandemic. The aim of this study was to measure the seroprevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) in the general population of Kosovo by gender, age group and region and among asymptomatic people. Method: The Institute of Public Health of Kosovo conducted a cross‐sectional population‐based survey, aligned with the protocols of the WHO Unity Studies, from the beginning of May to the end of June 2021. Results: The survey covered a total of 2204 people with a response rate of 91.8% (41.9% [923] males and 51.2% [1281] females). In May to June 2021, the prevalence of antibodies in the overall population (IgG antibodies ≥ 1.1) was 37.0%. Seroprevalence was 34.4% in men and 38.9% in women (p < 0.05), with the highest percentage (48.7%) found in the 60–69 years' age group. The overall prevalence of acute IgM antibodies (IgM ≥ 1.1) was 1% (95% CI: 0.7%–1.5%), with no significant difference between genders and the highest prevalence among participants of 60–69 years of age (1.6%; 95% CI: 0.7%–3.6%). Conclusion: A high prevalence of antibodies against SARS‐CoV‐2 was found in Kosovo before the start of the vaccination campaign. However, the results of the survey suggested that, by the end of June 2021, a desirable level of protection from the SARS‐CoV‐2 virus had not been reached. [ABSTRACT FROM AUTHOR]

Toxoplasmosis is a common cosmopolitan parasitic zoonosis caused by Toxoplasma gondii. Most often asymptomatic, toxoplasmosis can be serious for the foetus if it occurs during pregnancy. The objective of this study was to estimate the seroprevalence of toxoplasmosis among female students to contribute to the knowledge of the epidemiology of this disease. We conducted a cross-sectional study on female medical students in Bouake. The students were included after obtaining informed consent and were interviewed about their socio-demographic characteristics, gynaeco-obstetric history, factors favouring toxoplasmosis, and blood samples were collected. The samples were analysed by ELISA at the Bouake University Hospital laboratory. The collected data were entered and analysed using Word, Excel 2013, and Epi Info 7. The 168 female students included had an average age of 24 years, were married (6%), had a history of pregnancy (23.8%), were nulliparous (91.7%), had a cat (39.3%), and ate undercooked meat (72%). An overall seroprevalence of 67.9% was observed, of which 66.7% was IgG and 3.6% IgM. There was a statistically significant relationship between anti-toxoplasma seropositivity, age and the presence of a cat in the family. The overall seroprevalence of toxoplasmosis among female students at the Bouake Medical Sciences training and research unit was high. Therefore, students whose serology was negative should be made aware of the need to have a check-up in the event of pregnancy, so that appropriate measures can be taken as soon as possible. [ABSTRACT FROM AUTHOR]

Background: Equine herpesvirus (EHV) can cause respiratory, reproductive and neurological diseases in equine animals, including donkeys. The main pathogens responsible for these diseases are EHV type 1 (EHV‐1) and EHV‐4. In this study, we collected serum samples from 230 donkeys on 27 large‐scale donkey farms to detect EHV‐1 and EHV‐4 antibodies. We analyzed the presence of EHV antibodies based on region, age and season. Results: Out of the 27 farms, 62.96% (17/27) tested positive for EHV. Of the 230 donkeys tested, 2.61% (6/230) were positive only for EHV‐1, 5.22% (12/230) were positive only for EHV‐4, and 4.78% (11/230) were positive for both EHV‐1 and EHV‐4. The highest percentage of positive donkeys (21.28%) was found in Dong'e County. The seropositivity rate among donkeys aged 1–4 years was significantly higher compared to the group of donkeys aged 0–1 year (p < 0.05). Additionally, the positive rate was significantly higher in fall and winter compared to spring and summer (p < 0.05). Conclusions: Altogether, our findings indicate that large‐scale donkey farms in the Liaocheng area have a high prevalence of EHV antibodies. Since Liaocheng is an important donkey trading market in Shandong Province, it is crucial to consider the risk of disease transmission based on our test results. This will help in early detection and prevention of EHV outbreaks. [ABSTRACT FROM AUTHOR]

Background: Infectious bursal disease (IBD) is a viral infectious disease that affects young chicks. A cross‐sectional study was conducted from October 2020 to June 2021 to determine seroprevalence and associated risk factors of IBD on backyard chickens of purposively selected three districts of Buno Bedelle Zone, Southwestern Ethiopia. Methods: The study was carried out via a collection of serum samples, questionnaire surveys, and a total of 768 serum samples were collected from randomly selected backyard chickens of the study areas and examined for the presence of IBD virus. These serum samples were processed by using an indirect enzyme‐linked immunosorbent assay test procedure in laboratories. SPSS version 20 was used for data analysis and descriptive statics techniques were used. Results: Out of a total serum samples collected, 361 of them were found positive for the disease with an overall seroprevalence of 47%. Different seroprevalence rates of IBD with 55.9%, 43.3% and 41.2% were recorded in Didessa, Chora and Gechi districts, respectively. The result indicated that there was statistically significant difference (p < 0.05) of the disease among the three districts. Among the nine Peasant Associations (PAs) observed for seroprevalence of IBD, highest (62.9%) and lowest (34.20%) seroprevalence of the disease was recorded in Yembero and Shengela PAs, respectively. However, IBD was statistically significant in only Shengela PA of Chora district (p = 0.04, OR = 1.93 and 95% CI 1.04–3.58) and Seko PA of Gechi district (p = 0.05, OR = 1.79 and 95% CI 1.01–3.16). Even though sex, breed, age, source and management‐based seroprevalence was observed in the present study, the result indicated that there was only statistical significant difference (p = 0.004, OR = 0.62 and 95% CI 0.45–0.86) seen in which higher seroprevalence of IBD was determined in exotic (50.3%) than in local (38.6%) chickens breeds of the study areas. Conclusion: Generally, higher seroprevalence of IBD in the present study indicates a widely distribution of the disease and one of the potential threats for poultry production in the study areas. So, chicken vaccination and improved management system should be warranted in order to control the disease effectively. [ABSTRACT FROM AUTHOR]

Background: People experiencing homelessness are at greater risk of exposure and poor health outcomes from COVID-19. However, little data exist on the prevalence and correlates of COVID-19 among homeless populations. Tomitigate the spread and severity, uptake of the COVID-19 vaccine is needed. This can be challenging among youth experiencing homelessness who are more likely to be unvaccinated when compared to stably housed youth. Objective: We conducted this study to determine the prevalence and correlates of COVID-19 among youth experiencing homelessness. Methods: We examined experiences of COVID-19 symptoms, self-report of infection, and rates of COVID-19 antibodies and distinguished between natural and vaccinated immunity among youth experiencing homelessness (N = 265) recruited in one large metropolitan area in the south. Results: Based on self-report, very few participants experienced any symptoms, and 80%had never been diagnosed with COVID-19. Of those with COVID-19 antibodies (68%), the proportion with antibodies resulting from natural infection was 44%. The vaccination rate was 42%. Younger and vaccinated participants and those in shelters were likelier to have COVID-19 antibodies. Black and Hispanic youth were more likely than White youth to have had COVID-19. Those who adopted only one or two prevention behaviors were more likely to acquire a natural infection than those who adopted three or more prevention behaviors. Discussion: Youth experiencing homelessness report low vaccination rates, disrupted access to healthcare and social supports, and underlying chronic conditions, which may explain why they face poorer outcomes when infected with COVID-19. Vaccination and risk mitigation strategies to combat the high prevalence of COVID-19 are especially needed for sheltered youth who are at high risk yet are often asymptomatic. [ABSTRACT FROM AUTHOR]

Dengue is a highly prevalent mosquito-borne disease that is endemic in over 100 countries. It has a wider impact in terms of severity of illness and mortality risk in the absence of an effective vaccine as yet. The purpose of this study was to use meta-analysis to find out how common the dengue virus (DENV) is in India based on public data and to figure out how much of a problem. We searched, read, and reviewed about DENV in India that were available online. Forty-four cross-sectional studies were selected from the 178 records. There were reports of dengue cases in 14 out of the 28 states. Out of the patients presenting with symptoms of Dengue 27% of people were confirmed to have DENV infection with 82.29% (95% CI. 81-84%), having dengue IgM, 41.67% (95% CI: 40.16-43.43), having dengue IgG, and 23.97% (95% C.I. 14-43%), having both IgG and IgM from positive sample n=27156. Hospitalbased cross-sectional studies on suspected Dengue-like illness (DLI) found that 99.48% of people had confirmed dengue out of the patients with features of DLI, and community-based studies found that 0.52% of DLI cases had dengue. The seroprevalence rates for East, South, North, and Western regions were 35.38% (95% C.I.14-31%), 11.57% (95% C.I. 2-69%), 38.10% (95% C.I. 9-61%), and 14.87% (95% C.I. 6-38%) correspondingly. DENV is interestingly spreading across the whole country, and the disease's frequency varies a lot from place to place and from 2010-2023. However this review does not find appropriate published literature from 50% of the Indian states. The identification of IgG-class antibodies to dengue virus is indicative of prior exposure to this pathogen. Almost all immunocompetent individuals should have developed IgG antibodies against the dengue virus within three weeks of exposure. The presence of dengue virus IgM-class antibodies is indicative of an acute phase of infection. National Vector borne Disease Control Programme (NVBDCP) has some surveillance information, appropriate designed research into prevalence and risk factors for DENV infection would be required to provide adequate information for public health intervention. [ABSTRACT FROM AUTHOR]

Background: Although the diverse communities of tick-borne viruses (TBVs) have recently been proposed, the threat of infection and exposure to TBVs among humans across Kenya has been poorly understood. Objective: Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne viral agent associated with the epidemic of severe fever with thrombocytopenia syndrome (SFTS) disease in East Asian countries. This study investigated the seroprevalence of SFTSV among humans in Kenya. Methods: Serum samples were collected from 459 healthy people in Kenya and tested for anti-SFTSV antibodies, which were further confirmed by immunofluorescence assays. Micro neutralization assays were performed to identify neutralising antibodies against SFTSV and SFTSV-related viruses. Results: A high seroprevalence (162/459, 35.3%) of SFTSV was found in the samples from nine of the ten surveyed counties in Kenya, with higher rates in the eastern plateau forelands, semiarid and arid areas, and coastal areas than in the area aside Rift valley. The seropositive rate was slightly higher in women than in men and was significantly higher in the 55-64 age group. Neutralising activity against SFTSV was detected in four samples, resulting in a rate of 0.9%. No cross-neutralising activity against the SFTSV-related Guertu virus and Heartland virus was detected in the anti-SFTSV positive serum samples. Conclusion: The results provide serologic evidence of human exposure to SFTSV in Kenya and extend our understanding of SFTSV prevalence from Asia to Africa. The findings suggest an increasing threat of exposure to emerging TBVs and the need to investigate tick viromes in Kenya. [ABSTRACT FROM AUTHOR]

To estimate the size of COVID-19 waves using four indicators across three pandemic periods and assess potential surveillance bias. Case study using data from one region of Switzerland. We compared cases, hospitalizations, deaths, and seroprevalence during three periods including the first three pandemic waves (period 1: Feb–Oct 2020; period 2: Oct 2020-Feb 2021; period 3: Feb–Aug 2021). Data were retrieved from the Federal Office of Public Health or estimated from population-based studies. To assess potential surveillance bias, indicators were compared to a reference indicator, i.e. seroprevalence during periods 1 and 2 and hospitalizations during the period 3. Timeliness of indicators (the duration from data generation to the availability of the information to decision-makers) was also evaluated. Using seroprevalence (our reference indicator for period 1 and 2), the 2nd wave size was slightly larger (by a ratio of 1.4) than the 1st wave. Compared to seroprevalence, cases largely overestimated the 2nd wave size (2nd vs 1st wave ratio: 6.5), while hospitalizations (ratio: 2.2) and deaths (ratio: 2.9) were more suitable to compare the size of these waves. Using hospitalizations as a reference, the 3rd wave size was slightly smaller (by a ratio of 0.7) than the 2nd wave. Cases or deaths slightly underestimated the 3rd wave size (3rd vs 2nd wave ratio for cases: 0.5; for deaths: 0.4). The seroprevalence was not useful to compare the size of these waves due to high vaccination rates. Across all waves, timeliness for cases and hospitalizations was better than for deaths or seroprevalence. The usefulness of indicators for assessing the size of pandemic waves depends on the type of indicator and the period of the pandemic. [ABSTRACT FROM AUTHOR]

Fasciola hepatica, also known as the common liver fluke, is a globally distributed trematode parasite responsible for high economic losses in ruminants. Infection with F. hepatica occurs in Polish cattle and sheep; however, very little is known about its occurrence in goats. Therefore, a serological and coproscopic survey was carried out in Polish goats to determine the herd-level prevalence of F. hepatica infection in the goat population of Poland. Between 2014 and 2022, 33 randomly selected goat herds were serologically screened in the regions of Poland for which risk of F. hepatica infection was estimated as increased based on the spatial distribution model developed within the frame of the GLOWORM project. Virtually all adult goats (>1 year-old) were tested using a commercial MM3-SERO ELISA. Risk factors for seropositive herd status were analysed in contingency tables. Also, faecal samples from 214 goat herds monitored for gastrointestinal nematode infections and anthelmintic resistance were examined using a sedimentation method. At least one seropositive goat was detected in 11 of 33 herds, indicating herd-level seroprevalence of 33.3% (95% confidence interval (CI 95%): 19.7%–50.4%). At the animal level, only 17 of 1,464 tested goats were seropositive (1.2%, CI 95%: 0.7%–1.9%). The within-herd seroprevalence ranged from 0.8% to 11.1%. The serological status of the herd was not significantly associated with the characteristics of the herd or the extent of contact with sheep. In one herd, located in central Poland, a single positive faecal sample was found indicating a herd-level prevalence of F. hepatica infection of 0.5% (CI 95%: 0.1%–2.6%). The animal's post-mortem examination revealed liver lesions typical of chronic fasciolosis. F. hepatica infection occurs sporadically in Polish goat population and its prevalence is much lower than in cattle or sheep. Therefore, treatment or prevention of fasciolosis should only be considered if it has been reliably confirmed by an accurate diagnostic test. This applies also to goats inhabiting geographical areas where F. hepatica infection appears to be widespread in cattle and sheep, very likely due to the fact that goats avoid wet areas. [ABSTRACT FROM AUTHOR]

Background: HEV is endemic in several Middle Eastern countries including Saudi Arabia, which hosts the annual pilgrimage for Muslims from around the world. One of the Hajj rituals is the sacrifice of animals, including camels, cows, goats, and sheep. HEV Zoonosis is established in swine and other suspected species, including deer, rabbits, dromedary, and Bactrian camels. HEV was identified in small, domesticized animals like goats, cows, sheep, and horses. We previously investigated HEV seroprevalence in Camels. This study aimed to evaluate HEV seroprevalence in other highly consumed ruminants in Saudi Arabia, namely cows, sheep, and goats. Methods: Sera from cows (n = 47), goats (n = 56), and sheep (n = 67) were analyzed for the presence of HEV-IgG by using in-house developed ELISA assays. Results: The highest seroprevalence was found in sheep (62.7%), followed by cows (38.3%), and then goats (14.3%), with a p-value of < 0.001. No other demographic characteristics of the animals were significantly correlated with the HEV seroprevalence. Conclusions: This study provides baseline data as the first study on the seroprevalence of HEV in ruminant animals in Saudi Arabia. The high seroprevalence found in sheep and cows must be further investigated for the potential zoonotic HEV transmission to humans. Further studies are needed to investigate the active viremia in these animal species through nucleic acid detection and sequencing to provide data on the circulating HEV genotypes among the targeted animal species. The detection of HEV in different animal products, such as milk, liver, and others, also remains an important study area to consider. [ABSTRACT FROM AUTHOR]

Background: The objective of this study is to analyze the transplacental transmission of SARS-CoV-2 antibodies, their persistence in newborns, the factors that may influence this transmission, and the protection these antibodies confer over time. Methods: This prospective cohort was conducted in a tertiary pediatric hospital in the Barcelona Metropolitan Region, Spain. It included neonates born to mothers who had SARS-CoV-2 infection during pregnancy or delivery between August 2020 and January 2022. We followed the recruited children for at least six months, and blood tests were performed to determine the presence of SARS-CoV-2 antibodies. Results: A total of 101 children were recruited. Among the serologies performed on children under three months of age, 44/82 were positive (53.7%). Newborns whose mothers presented more severe disease exhibited higher seropositivity odds (coefficient 9.747; p = 0.002). There were increased preterm deliveries when maternal infection occurred closer to the time of delivery. No severe SARS-CoV-2 infections were detected in children during the follow-up. Conclusions: Slightly more than half of the SARS-CoV-2 serologies performed in the first three months were positive. This appears to confer protection during early childhood. The severity of maternal infection is the most significant factor influencing the transmission of antibodies in children born to unvaccinated mothers. [ABSTRACT FROM AUTHOR]

Historical seroprevalence data for Anisakis in Spain vary greatly depending on the sampling region owing to different fish consumption habits. As a result of European Regulation (EC) No. 853/2004, the Royal Decree 1420/2006 on the prevention of parasitosis by Anisakis in fishery products supplied by establishments that serve food to final consumers or to communities came into force in Spain. In this study, a prevalence study of Anisakis in Madrid has been conducted to verify the prophylactic effects of the application of the law. Sera from 500 blood donors from the Fundación Jiménez Díaz University Hospital (Madrid/2021–2023) were collected, and the levels of anti-Anisakis IgG, IgA, and IgE were analyzed by ELISA, comparing them with those obtained with 110 donors from the Red Cross and the "Gómez Ulla" Central Defense Hospital (Madrid/2001–2002). The percentages of positivity in the 2021–2023 donor group were IgG (13.6%), IgA (13.6%), and IgE (2.2%), while in the 2001–2002 donors they were positive for IgG (15.45%), IgA (14.54%), and IgE (11.65%). A reduction of more than 80% was observed in the prevalence of anti-Anisakis IgE in the healthy population of Madrid, which confirmed the positive effect of RD1420/2006, which was later incorporated into RD1021/2022. [ABSTRACT FROM AUTHOR]

Lyme borreliosis (LB), a tick-borne infection caused by bacteria in the Borrelia burgdorferi sensu lato complex, is increasingly prevalent on the Balkan Peninsula, including Bulgaria, where it is the most common tick-borne disease. This study aimed to assess the seroprevalence of LB across Bulgaria by analyzing 1892 serum samples for specific IgG antibodies using a two-tier testing protocol involving an ELISA and immunoblot methods. The results revealed an overall seroprevalence rate of 5.4%, with significant variation based on age, sex, and residence. Seroprevalence increased with age, peaking at 8.4% in individuals over 65 years. Males had a seroprevalence of 8.4% compared to 3.3% in females, and rural residents showed higher seroprevalence (10.2%) compared to urban residents (4.4%). Regional analysis indicated that seroprevalence ranged from 0.0% to 20.0%, with higher rates in northern provinces such as Gabrovo (18.9%) and Targovishte (20.0%). This study highlights the importance of two-step testing protocols for accurate diagnosis and underscores the need for increased awareness and further research to enhance public health measures and the management of LB in Bulgaria. [ABSTRACT FROM AUTHOR]

Brucellosis, a contagious bacterial disease affecting animals globally presents a substantial zoonotic risk that is frequently underestimated, hinders animal trade, and endangers livestock and human health. The present study was conducted from November 2023 to June 2024 in Central and North Gondar Zone, Ethiopia. The current cross-sectional study aimed to evaluate the prevalence of brucellosis and to explore the related knowledge, attitudes, and practices within the specified region. A total of 384 serum samples were collected via random sampling from 20 dairy farms located in Ethiopia. Both local and cross-breed samples screened using the Rose Bengal Plate test and confirmed through an enzyme-linked immunosorbent assay. The seroprevalence of bovine brucellosis for both tests was 17.71% overall, with 9.62% for Central Gondar and 27.27% for North Gondar. Extensive farms exhibited notably higher odds of brucellosis compared to intensive farms, with unadjusted crude odds ratios of 3.01 and adjusted odds ratios of 2.37, respectively. Medium-sized herds also demonstrated increased odds in the multivariate analysis compared with small herds. Young respondents displayed the highest awareness levels, followed by adults and older individuals, with statistically significant differences observed across all categories. Regarding a semi- structured survey from 150 farmers on the association between sociodemographic data and knowledge, females exhibited higher awareness levels, with 117 (80.14%) responding positively. Young respondents showed a higher positive response rate of 58% compared to adults (52.7%) and the elderly (36.54%). In conclusion, these results emphasize the need for comprehensive strategies to address the factors influencing bovine brucellosis prevalence and respondent awareness. [ABSTRACT FROM AUTHOR]

Humans are infected by Toxoplasma gondii worldwide and its consequences may seriously affect an immune deprived population such as HIV and transplanted patients or pregnant women and foetuses. A deep knowledge of toxoplasmosis seroprevalence in Spain is needed in order to better shape health policies and educational programs. We present the results of the first systematic review and meta-analysis on the human prevalence for this disease in Spain. Databases (PubMed, Web of Science, SCOPUS and Teseo) were searched for relevant studies that were published between January 1993 and December 2023 and all population-based cross-sectional and longitudinal studies reporting the human seroprevalence in Spain were revised. Within the population analysed, our targeted groups were immunocompetent population, pregnant women and immunocompromised patients. Among 572 studies and 35 doctoral theses retrieved, 15 studies and three doctoral theses were included in the meta-analysis. A random effects model was used for the meta-analyses due to the high heterogeneity found between studies (I2: 99.97), since it is a statistically conservative model, in addition to allowing better external validity. The global pooled seroprevalence was 32.3% (95% CI 28.7–36.2%). Most of the studies carried out were in pregnant women and the meta-analysis reported that the pooled seroprevalence of toxoplasmosis in pregnant women in Spain was 24.4% (24,737/85,703, 95% CI 21.2–28.0%), based on the random effects model. It is recommended to continue monitoring the seroprevalence status of T. gondii in order to obtain essential guidelines for the prevention and control of the infection in the population. [ABSTRACT FROM AUTHOR]

Abstract Background Chad with 7,698 confirmed cases of infection and 194 deaths since the beginning of the COVID-19 pandemic, is one of the African countries with the lowest reported case numbers. However, this figure likely underestimates the true spread of the virus due to the low rate of diagnosis. The high rate of asymptomatic infections reflects the reality of SARS-CoV-2 transmission in Chad. In this study, we estimated the seroprevalence and identified factors associated with SARS-CoV-2 infection. Methods A cross-sectional study was conducted between September 2022 and February 2023. A total of 1,290 plasma samples were collected from outpatient attendees at Health Facilities located in 11 provinces of Chad and tested by ELISA method, for the presence of IgG antibodies to SARS-CoV2 nucleocapsid (N) protein. KoboToolbox was used to gather data from the participants and data were analyzed using STATA 16. Results The overall seroprevalence was 83.0% [95% CI = 81.6%—85.5%], with variations between provinces, ranging from 99.2% [95% CI = 94.0%—100%] in Moundou (Southern Chad) to 46.8% [95% CI = 36.0% -57.1%] in Biltine (Eastern Chad). Factors associated with the seroprevalence included military occupation (OR = 0.37 CI [0.80–1.77] p = 0.025) and age group between 55–64 years (OR = 0.33 CI [0.15–0.72] p = 0.005). While, other factors, such as gender and age were not significantly associated with seroprevalence. Conclusion Our results indicated that, the seroprevalence of COVID-19 in Chad is among the highest in Sub-Saharan Africa. These estimates could guide the response and public health policy decisions, enhancing the management of future outbreaks involving respiratory pathogens.

Abstract Objectives People living with HIV (PLWH) are a risk group for severe symptoms and higher mortality during COVID-19. We analyzed the dynamic rise of SARS-CoV-2 seroprevalence induced by coinfections and vaccinations in PLWH in the first three years of the pandemic in Germany and compared it with corresponding data available for the general population. Methods Each month on average 93 blood samples from the German HIV-1 Seroconverter Cohort, a prospective longitudinal multicenter study that includes PLWH whose date of seroconversion is well defined, were received. The samples from 1569 PLWH were tested for the presence of anti-S1 and if positive, also for anti-N antibodies. Results In 2020 the number of anti-S1 positive cases/month was between 0.0 and 6.9% (average 1.6%). Since then the anti-S1 prevalence increased reaching already 35% (33/94) in May 2021. At that time 3.2% of the cases were also anti-N positive. In 2022 the average anti-S1 seroprevalence reached 97.5%. In the vaccination era a positive anti-N response was associated with a younger age and females were overrepresented among anti-S1/anti-N negative samples (assuming no vaccination or infection). Conclusions The average 1.6% anti-S1 seroprevalence in the cohort in 2020 was comparable to that in the general population (1.3%). The increase in anti-S1 seroprevalence in the first half of 2021 occurred slightly earlier. This increase was likely caused by the prioritization of PLWH at the early stage of the vaccination campaign and by infections during the third wave of the pandemic.

Introduction Dengue is one of the most serious and rapidly spreading major mosquito borne diseases in the world. Despite many acute febrile illnesses in Tchad, the burden of illness due to dengue in the country is largely unknown. Hence, the present study aimed to determine the seroprevalence of dengue viral (DENV) infection and its association with hematological parameters. Method A cross sectional study was carried out in Bongor Provincial Hospital. Blood samples were collected from each participant and were used to determine the hematological profile and to diagnose the presence of DENV infection. A total of 130 participants were enrolled in the study. Among these, 114 (87.7%) were diagnosed positive for DENV infection. Results The majority of the positive cases were of the age group 21 to 40 years old. Leukocytosis was the most common hematological parameter affecting 120 (92.3%) of them followed by anemia and thrombocytopenia affecting 69 (53.1%) and 16 (12.3%) of them, respectively, and then lymphocytosis affecting 5 (3.8%) of them. No case of leukopenia was recorded. Discussion The seroprevalence rate among participants suggests that the dengue virus is in circulation in Mayo Kebbi province: south of Tchad. The abnormal hematological parameters may contribute to the severity of the infection like the incidence of bleeding in the case of thrombocytopenia.

Background Hepatitis B virus (HBV) and Hepatitis C virus (HCV) show similarity in the transmission, distribution, hepatotropism, and leading to chronic asymptomatic infection. Coinfection of HBV and HCV can lead to more severe liver disease and an increased risk for progression to hepatocellular carcinoma (HCC). Most of the people with chronic infection are unaware of their HBV and HCV infections, hence facilitating these to go undiagnosed until these viruses have caused serious liver damage and they act as a potential source of infection for the community at large. Therefore, the present study aimed to find the prevalence of HBV and HCV along with incidences of coinfection of HBV and HCV in patients seeking hospital care in central India. Methods A five-year hospital-based study was carried out at the tertiary care hospital in Central India from 2018 to 2022. A total of 72402 patients attending the outdoor patients and admitted indoor patients who were advised for HBV and HCV for screening before any invasive/surgical procedure and patients who presented with symptoms of acute or chronic liver disease were included in this study. Screening was done by immunochromatography-based card test followed by the confirmation of all samples by enzyme immunoassay. Results Seroprevalence of HBV and HCV was found to be 3.71% and 1.91%, respectively. Coinfection with HBV/HCV was seen in 0.13% of the individuals. The overall prevalence of HBV, HCV, and HBV-HCV coinfection was significantly higher in the male population as compared to females. Conclusion The study findings of seroprevalence of HBV and HCV among the hospital-based population will help to get a baseline understanding of the disease burden in central India. The HBV/HCV coinfection rate also raises serious concerns owing to its high prevalence rate among the younger age.

Abstract Hepatitis C virus (HCV) transmission remains a significant public health concern. It is well documented globally, however, Nowshera district, Pakistan, is lacking such profile. This study aims to explore the relationship between HCV infection and several risk factors, including socio-demographic, clinical and personal life-style factors. This study using a cross-sectional design, examined 606 randomly selected individuals visiting the Pathology department at Qazi Hussain Medical Complex and District Headquarter (DHQ) Hospital Nowshera between May 1, 2022 and Jun 30, 2023. This research investigation employed a methodical approach involving formal interviews in conjunction with structured questionnaires to gather comprehensive information related to socio-demographic characteristics, clinical history, and personal hygiene practices. We collected 10 ml of blood samples and tested the separated serum to identify markers using the Immuno-Chromatographic Test (ICT) and the Enzyme-Linked Immunosorbent Assay (ELISA). IBM SPSS Statistics version 27 was used for data analysis. To measure the association between dependent variable and independent variables, a chi-square and risk analysis was carried out; multiple logistic regression was employed for modeling the risk factors associated with independent variable. A statistical significance level was established at a P-value of less than 0.05. In present study, which included 606 participants, 12% were found to be infected with HCV. Importantly it revealed that facial shave at barber (adjusted odds ratio, aOR = 40.65, p = 0.000) represents the most prevalent mode of HCV transmission. Additionally, a strong association was observed between HCV infection and history of past surgery (RR = 2.98, p = 0.001), HCV infected family member (aOR = 4.28, p = 0.001), workplace injuries (aOR = 6.68, p = 0.000), history of hospital admission (RR = 2.09), practicing ear and nose piercing (aOR = 5.01, p = 0.001), dental treatment (RR = 2.31) and the frequency of injections (aOR = 8.607, p = 0.000). These findings underscore the pressing need for targeted interventions. This study highlights the paramount importance of understanding the modes of HCV transmission and their associated risk factors. The results emphasize the need for educational initiatives, both within the healthcare sector and among the general public, to combat HCV transmission effectively. By implementing sterilization procedures and increasing awareness, we can make significant strides in reducing the burden of HCV infection. Moreover, proactive measures within families can help contain the spread of the virus, ultimately contributing to improved public health.

Abstract Introduction The development of a potent immune response and antibodies against SARS-CoV-2 is important for herd immunity. The serological response may be due to a previous infection or vaccination. Healthy blood donors could represent and provide information on the immune status of the general population. Therefore, we estimated the global and regional prevalence of SARS-CoV-2 antibodies among healthy blood donors. Methods We conducted a systematic search of PubMed, Scopus, and ProQuest from December 2019 to January 2023. After critical appraisal and quality assessment, a qualitative synthesis of the identified relevant articles was performed. The random-effects model was used to estimate the pooled prevalence of SARS-CoV-2 antibodies. Funnel plots and Egger’s test were used to assess publication bias. Sensitivity analysis was performed, and heterogeneity was quantified using I 2 statistics. Results A total of 70 peer-reviewed articles were selected that together included 2,454,192 blood donors. The global estimated pooled prevalence of SARS-CoV-2 antibodies among healthy blood donors was 10.3% (95% CI: 4.6 – 18.0%, n = 70). The highest seroprevalence was observed in Asia (17.7%), followed by Africa (16.1%). The seroprevalence in studies conducted before the introduction of the vaccine was 6.1%, whereas those of studies conducted after vaccines were available was 27.6%. High seroprevalence was observed in studies that measured antibodies against the S protein of the virus (15.2%), while lower (12.5%) in those that measured antibodies against the N protein. A high seroprevalence was observed in studies that only measured IgG antibodies (16.3%), and it was 5.9% in studies that measured total antibodies. Conclusion The prevalence of SARS-CoV-2 antibodies among healthy blood donors varies, potentially indicating geographical disparities in transmission and vaccination rates. To enhance community resilience, addressing these differences through inclusive health policies and adaptable public health measures is crucial.

Abstract Background Understanding the level of exposure to Lassa virus (LASV) in at-risk communities allows for the administration of effective preventive interventions to mitigate epidemics of Lassa fever. We assessed the seroprevalence of LASV antibodies in rural and semiurban communities of two cosmopolitan cities in Nigeria with poorly understood Lassa epidemiology. Methods A cross-sectional study was conducted in ten communities located in the Abuja Municipal Area Council (AMAC), Abuja, and Ikorodu Local Government Area (LGA), Lagos, from February 2nd to July 5th, 2022. Serum samples collected from participants were analyzed for IgG and IgM antibodies using a ReLASV® Pan-Lassa NP IgG/IgM enzyme-linked immunosorbent assay (ELISA) kit. A questionnaire administered to participants collected self-reported sociodemographic and LASV exposure information. Seroprevalence of LASV IgG/IgM was estimated overall, and by study site. Univariate and multivariate log-binomial models estimated unadjusted and adjusted prevalence ratios (aPRs) and 95% confidence intervals (CI) for site-specific risk factors for LASV seropositivity. Grouped Least Absolute Shrinkage and Selection Operator (LASSO) was used for variable selection for multivariate analysis. Results A total of 628 participants with serum samples were included in the study. Most participants were female (434, 69%), married (459, 73%), and had a median age of 38 years (interquartile range 28–50). The overall seroprevalence was 27% (171/628), with a prevalence of 33% (126/376) in Abuja and 18% (45/252) in Lagos. Based on site-specific grouped LASSO selection, enrollment in the dry season (vs. wet; aPR, 95% CI: 1.73, 1.33–2.24), reported inconsistent washing of fruits and vegetables (aPR, 95% CI: 1.45, 1.10–1.92), and a positive malaria rapid test (aPR, 95% CI: 1.48, 1.09-2.00) were independently associated with LASV seropositivity in Abuja, whereas, only a self-reported history of rhinorrhea (PR, 95% CI: 2.21, 1.31–3.72) was independently associated with Lassa seropositivity in Lagos. Conclusions The LASV seroprevalence was comparable to that in other areas in Nigeria. Our findings corroborate those from other studies on the importance of limiting human exposure to rodents and focusing on behavioral factors such as poor hygiene practices to reduce exposure to LASV.

The aim of the study was to determine the prevalence of leptospiroses and hemorrhagic fever with renal syndrome (HFRS) among residents of some administrative districts of the Leningrad Region. Materials and methods. 958 blood serum samples of conventionally healthy individuals living in the following territories of the Leningrad Region: Boksitogorsky, Volosovsky, Vyborgsky, Kingiseppsky, Lodeynopolsky, Luzhsky, Podporozhsky, Priozersky, Slantsevsky and Tikhvinsky districts – were analyzed by enzyme immunoassay. The retrospective epidemiological analysis of the incidence of leptospirosis and HFRS in the population of the Leningrad Region in 2011–2020 was carried out based on the data from the Rospotrebnadzor Administration and Forms No. 2 “Information on infectious and parasitic diseases”. Results and discussion. All in all, 54 cases of leptospirosis and 104 cases of HFRS were registered in the Leningrad Region in 2011–2020. The long-term average annual incidence rate (LTAAIR) for leptospirosis was 0.32. In Boksitogorsky, Vyborgsky, Lodeynopolsky, Podporozhsky and Slantsevsky districts, cases of leptospirosis were not recorded, but IgG-antibodies to Leptospira interrogans were detected in residents of those areas. The LTAAIR for HFRS was 0.63. There are no registered cases of HFRS in the Kingiseppsky, Podporozhsky, and Slantsevsky districts. IgG-antibodies to Orthohantavirus were detected in volunteers in all surveyed areas. The detection of specific antibodies in the blood sera of conventionally healthy people living in the Leningrad Region indicates contact of the population with pathogens of leptospirosis and HFRS. The lack of registered morbidity in some areas is probably due to their hypo-diagnosis, as evidenced by the detection of antibodies to the pathogens of these infections in people living in the corresponding territories.

Abstract Severe fever with thrombocytopenia syndrome (SFTS), a tick-borne disease caused by Dabie bandavirus (SFTSV) is an emerging infectious disease of substantial concern in East Asia. In 2019, Ongkittikul S et al. reported the first case of SFTS in Thailand. Our report describes a One Health investigation of SFTS zoonosis examining the index case and suspected animal reservoirs using real-time RT-PCR and immunoassays. We add to the report on the first confirmed case of SFTSV infection in a human in Thailand by conducting a limited but informative One Health surveillance study. Dogs and cats tested positive for SFTSV antibody using IgG ELISA. We conclude that domestic dogs and cats might serve as potential reservoirs for SFTSV spread due to their closer proximity to the index case than other non-domestic animals. Notably, we did not detect SFTSV in synanthropic cats or dogs—nor did we detect SFTSV in Rhipicephalus sanguineus ticks—using RT-PCR. We propose that One Health investigations coupling genomic and serologic assays in response to new SFTS cases could play a pivotal role in preventing and managing SFTS among humans and animals in East Asia. As such, we are establishing a collaborative response to SFTS in Thailand through human outbreak investigations that align with principles of One Health, through environmental surveys and animal RT-PCR and immunoassays. Our investigation highlights the importance of coupling RT-PCR with seroprevalence assays as principal elements of One Health surveillance for SFTS in order to shed light on potential animal reservoirs and track emerging zoonosis.

Abstract Background Cytomegalovirus (CMV) is the most common congenital infection in pregnancy with potential long-term adverse effects on the fetus. There is limited data on CMV seroprevalence in pregnant women in Singapore, with last reported study dating back over two decades. We look at the latest CMV seroprevalence in antenatal population in Singapore. Methods Between January 2021 and August 2021, 385 pregnant women receiving antenatal care at Singapore General Hospital were randomly selected for CMV IgG test to be performed on their blood samples collected during the first trimester of their pregnancies. Positivity for CMV IgG represents past exposure prior to pregnancy. Results Overall CMV seroprevalence was 71.7% (276/385) (95% CI 067, 0.76, p value

Lumpy skin disease (LSD) is an infectious disease of cattle caused by lumpy skin disease virus (LSDV), which is a member of the Poxviridae family and genus Capripoxvirus. The illness is marked by mild to severe symptoms, including edema, fever, lymphadenitis, widespread skin nodules, and infrequently, death. In spite of its significance, little is now understood about the magnitude and predisposing factors in Tanzania. The aim of this study was to determine the seroprevalence of LSD in cattle within Kilolo district, and to identify key predisposing factors. A cross-sectional study was conducted in 17 villages within Kilolo district from February to March 2024 to estimate the seroprevalence of LSD in cattle. A total number of 276 serum samples was obtained from 65 cattle herds and a Double Antigen ELISA (ID Screen®) (IDVet, France) was used to screen for LSDV antibodies. Logistic regression analysis was employed to assess the risk factors for LSD seropositivity. The overall animal- and herd-level seroprevalence were 18.1% (95% CI: 13.98–23.14) and 44.6% (95% CI: 7.54–15.38), respectively. The highest individual animal level seroprevalence was documented in Irindi village 39.1% (95% CI: 5.36–12.24), followed by Masalali 38.5% (95% CI: 6.25–13.50), Ng’uruhe 37.5% (95% CI: 5.65–12.66), Irole 33% (95% CI: 1.5–6.10), and Utengule 26.5% (95% CI: 3.07-8.81) with significant differences (p=0.003). The seroprevalence of LSD varied significantly (P2 years having a higher seroprevalence (29.8%, 95%CI, 52.27–64.21) than yearlings aged 1-2 years (5. 6%, 95%CI, 9.31–17.60) and calves (0.0%, 95%CI, 23.36-34.35). Sex (Female/male, OR=2.0937, 95%CI, 1.4642-3.0248), age (Yearling/Adult, OR=0.1756, 95%CI, 0.0841-0.3730), village (OR=0.8970, 95%CI, 0.8349-0.9636) and herd size (Large/small, OR=1.9464, 95%CI, 1.1597-3.2669) were significant risk factors for LSDV seropositivity in Kilolo district. Raising awareness among livestock owners and veterinary staff about the disease and its risk factors, vaccination and vector control measures should be prioritized to minimize the transmission of the disease.

Poultry farming is crucial for the livelihoods of small-scale producers in the Northen Benin, yet the industry faces challenges from diseases like ND, which threaten both poultry health and economic stability. This study investigates the seroprevalence of Newcastle Disease Virus (NDV) among indigenous chickens and guinea fowl in the Atacora and Donga regions of Northern Benin, addressing a significant gap in regional poultry health data. A cross-sectional study was designed, sampling a total of 300 birds, including 191 indigenous chickens and 109 guinea fowl, from six districts. Systematic random sampling was employed to select smallholder farms, and blood samples were collected for Hemagglutination inhibition (HI) tests to detect NDV antibodies. Statistical analyses, including chi-square tests, determined associations and differences in seroprevalence between regions and species. Results revealed notable variations in NDV seroprevalence between the two regions. In Atacora, 59.22% of chickens tested positive for NDV antibodies, with 52.33% of non-vaccinated and 94.12% of vaccinated chickens showing positive results. In Donga, the overall seroprevalence was 46.59%, with 27.78% of non-vaccinated and 59.62% of vaccinated chickens testing positive. A chi-square test indicated a significant difference in NDV seroprevalence between the two regions for chickens (x2 = 12.901; P = 0.024). For guinea fowls, seroprevalence was 63.53% in Atacora and 62.50% in Donga, with no significant difference observed (x2 = 1.102; P = 0.954). This study provides the first serological data on NDV prevalence in northern Benin, highlighting the endemic nature of NDV and the critical epidemiological role of guinea fowls due to frequent exposure and field infections, especially in the Atacora region. It recommends enhancing vaccination coverage, improving biosecurity measures, and conducting further research to isolate and characterize virus strains to develop more effective control strategies.

Background: The Human Cytomegalovirus (HCMV) is a type of beta herpesvirus widespread in all human populations. It is estimated that up to 80-100% of adults worldwide and most infections are harmless and can cause severe health complications in infants, like hearing loss and developmental issues. Still, immunocompromised individuals can experience serious complications from the virus. Unfortunately, there is limited information on the prevalence of this virus in our country, and no studies have been reported on the rate of CMV transmission yet. OBJECTIVES: This study aims to evaluate the levels of IgM antibodies against Cytomegalovirus (CMV) in East Singhbhum, West Singhbhum, and Seraikela Kharsawan using an ELISA test. Methods: An indirect ELISA test was performed to detect anti-CMV IgM and the period of study was from January’2021 to June’2023. Results: The examination tested 55 people for the TORCH profile of CMV parameters from regions of East Singhbhum, West Singhbhum, and Seraikela Kharsawan. Here, 17 people (30.09%) were IgM positive by ELISA. Conclusions: The serological data confirms that CMV is not being monitored and recognized in the general population, which limits our study between CMV infection, disease, and clinically diagnosed outcomes. This understanding is crucial for the healthcare and policy sectors. Thus, we recommend implementing a surveillance and mindfulness program for at least one-fourth of the population in Jharkhand and continuing to explore and develop effective vaccines to control CMV infections.

Background: Leptospirosis and Scrub typhus are zoonotic illnesses that are found worldwide. Scrub typhus is a rickettsial infection caused by Orientia tsutsugamushi and spread through the biting of a mite’s chigger. Leptospirosis is an anthropozoonotic illness that can be found anywhere but is most common in tropical and subtropical areas. In this study, we report the seroprevalence of Scrub typhus and Leptospirosis with relation to demographic factors in clinically suspected patients attending a tertiary care hospital in Theni, Tamil Nadu. Methods: This is a retrospective study in which 9574 serum samples from clinically suspected cases were collected from January 2018 to December 2023 and tested for immunoglobulin M (IgM) antibodies for Scrub typhus using the enzyme-linked immunosorbent assay (ELISA) and rapid test. A blood sample was taken from each patient, and an IgM ELISA was performed to make the diagnosis. The ELISA cut-off was determined. Results: In this study, 9574 probable cases, 4306 were examined for Leptospira IgM ELISA and 5268 for Scrub typhus IgM ELISA. Out of 4306 suspected Leptospira cases, 167 (3.8%) were positive and 485 (9.2%) were positive in 5268 suspected Scrub typhus cases. The bulk of Leptospirosis and Scrub typhus cases were in the 21–40 years’ age range, followed by the 0–20 years’ age range. Males were found to have higher seroprevalence (57.1%) than females (42.9%). Conclusions: Scrub typhus and leptospirosis are developing infections, and prompt treatment can save many lives. It is strongly advised to take a programmatic approach to the prevention, control, and management of these developing diseases.

Abstract Introduction Hantavirus infection is a zoonotic disease from rodents to humans, necessitating seroprevalence assessment for disease burden clarification and control measure implementation. This study aimed to estimate global hantaviruses seroprevalence, examining variations by regions, populations or settings. Methods A comprehensive database search identified studies on human hantaviruses seroprevalence using IgG detection until january 2024. A random-effects meta-analysis estimated pooled seroprevalence, with subgroup analyses for geographical region, population, setting or occupation. Results Out of 3,382 abstracts reviewed, 110 studies were selected, comprising 81,815 observations and 3207 events. The global seroprevalence was calculated at 2.93% (2.34%-3.67%). In terms of geographical distribution, our analysis encompassed 61 studies from the Americas, where the seroprevalence was estimated at 2.43% (95% CI: 1.71%—3.46%), 33 studies from Europe indicating a seroprevalence of 2.98% (95% CI: 2.19%—4.06%), 10 studies from Asia revealing a seroprevalence of 6.84% (95% CI: 3.64%—12.50%), and 6 studies from Africa demonstrating a seroprevalence of 2.21% (95% CI: 1.82%—2.71%). Subgroup analysis underscored varying seroprevalence rates across different populations, settings, and occupations, highlighting the necessity for targeted interventions and preventive measures. Conclusion The analysis reveals a moderate global hantaviruses seroprevalence, emphasizing the viral family's complex transmission dynamics influenced by exposure and geographical factors. This highlights the need for targeted prevention and control strategies.

Objective: To determine the seroprevalence of Varicella-zoster virus (VZV) in females of childbearing age. Study Design: Cross-sectional study. Place and Duration of Study: Virology Department, tertiary care hospital, Rawalpindi, from August 2022 to December 2022. Materials and Methods: A total of 200 females, aged 15-49 years, were included in the study. Data of the participants regarding age, socioeconomic status, marital status, and previous history of VZV infection was collected by a predesigned questionnaire. Blood samples were tested for the detection of VZV IgG by Enzyme Linked Immunosorbent Assay (ELISA) of Ratio Diagnostic, Germany. SPSS version 25 was used to analyze the data. Results: Out of total 200 samples, 163 (81.5%) were positive for VZV IgG and 37 (18.5%) were negative. The positivity of VZV IgG was highest in age group 2 (20-29 years) with 87 (43.5%) positive cases, followed by 54 (27%) in age group 3 (30-39 years) and 11 (5.5%) in both age group 1 (< 20 years) and age group 4 (40-49 years). Out of 200 participants, 158 (79.0%) were married and 42 (21.0%) were unmarried. Among total, 107 (53.5%) had history of previous VZV infection while 93 (46.5%) had no significant history. Conclusions: This study showed significant exposure of VZV in females of childbearing age and subsequent development of immunity. However, a substantial proportion of females were susceptible to VZV infection. This susceptibility in females could potentially pose a future risk of infection during pregnancy, resulting in severe complications and congenital abnormalities.

Abstract Background SARS-CoV-2, the causative agent of COVID-19, is a betacoronavirus belonging to the same genus as endemic human coronaviruses (hCoVs) OC43 and HKU1 and is distinct from alpha hCoVs 229E and NL63. In a study of adolescents in the Philippines, we evaluated seroprevalence to the hCoVs, whether pre-pandemic hCoV immunity modulated subsequent risk of SARS-CoV-2 infection, and if SARS-CoV-2 infection affected the transmission of the hCoVs. Methods From 499 individuals screened in 2021 for SARS-CoV-2 receptor binding domain (RBD) antibodies by enzyme-linked immunosorbent assay (ELISA), we randomly selected 59 SARS-CoV-2 negative and 61 positive individuals for further serological evaluation. We measured RBD and spike antibodies to the four hCoVs and SARS-CoV-2 by ELISA in samples from the same participants collected pre-pandemic (2018–2019) and mid-pandemic (2021), before COVID-19 vaccination. Results We observed over 72% seropositivity to the four hCoVs pre-pandemic. Binding antibodies increased with age to 229E and OC43, suggesting endemic circulation, while antibody levels was flat across ages for HKU1 and NL63. During the COVID-19 pandemic, antibodies increased significantly to the RBDs of OC43, NL63, and 229E and spikes of all four hCoVs in both SARS-CoV-2 negative and positive adolescents. Those aged 12–15 years old in 2021 had higher antibodies to RBD and spike of OC43, NL63, and 229E than adolescents the same age in 2019, further demonstrating intense transmission of the hCoVs during the pandemic. Conclusions We observe a limited impact of the COVID-19 pandemic on endemic hCoV transmission. This study provides insight into co-circulation of hCoVs and SARS-CoV-2.