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INTRODUCTION: The nose and throat are areas of high viral load, which could place otolaryngologists at an even higher risk for COVID-19 than other health-care workers. OBJECTIVE: To investigate the prevalence of antibodies against SARS-CoV-2 in otorhinolaryngologists in southern Brazil, its relationship to demographic data, professional practice and reported symptoms of COVID-19, and compare it with official data on other health-care workers of the state and the general population in the same period. METHODS: In this cross-sectional multicenter study, otolaryngologists actively practicing officially registered in Rio Grande do Sul were screened for IgM and IgG antibodies against SARS-CoV-2 from August 1 to September 15, 2020. A questionnaire was also applied. RESULTS: We screened 358 (80.1%) of 447 actively practicing otolaryngologists (195 [54.5%] male; mean [SD] age, 47.77 [13.57] years; range, 26-84 years). Twenty-three were positive for IgM and/or IgG (6.4%). This result was significantly associated with reports of infected household contacts (19/315 negatives and 8/23 positives; p 

The aim of this systematic review was to identify articles on prevalence of leptospirosis in stray and sheltered dogs worldwide and access the methodological quality of the recovered papers. Six databases (CABI, Cochrane, Pubmed, Scielo, Scopus and Web of Science) were searched, without restriction on year or location where the studies were performed. The search recovered 476 articles and 60 were selected for analysis according to quality criteria. None of the selected articles showed a complete explanation for the sample size adopted (probabilistic sampling), leading to the impossibility of recalculation of leptospirosis prevalence for stray or sheltered dogs. Among the analyzed papers 43.33% (26/60) showed five of the ten quality criteria analyzed, 16.67% (10/60) three, 15.00% (9/60) four, 10.00% (6/60) six, 6.67% (4/60) eight, only 5.00% (3/60) showed nine of the ten criteria analyzed, whereas two papers showed two [1.67% (1/60)] and seven [1.67% (1/60)] of the ten criteria assessed. The majority of the papers were published in the Americas [45.00% (27/60)] and in the last sixteen years (2003 to 2019) [81.67% (49/60)], and most of the sampled dogs were stray dogs [65.00% (39/60)]. The leptospirosis diagnostic test used more frequently was Micro Agglutination Test (MAT) [78.33% (47/60)] followed by polymerase Chain Reaction (PCR) [23.33% (14/60)], whereas the most common serovars identified were Canicola [71.43% (35/49)], Icterohaemohrragiae [65.31% (32/49)], Grippotyphosa [40.82% (20/49)] and Pomona [40.82% (20/49)]. In conclusion, our results showed that Leptospira spp. is present in stray and sheltered dogs worldwide, but the complete comprehension of the prevalence of leptospirosis in these populations could not be achieved due to the low methodologic quality of the recovered studies about leptospirosis in stray and sheltered dogs.

Resumen Introduccion A 30 de abril de 2020, se habian notificado 203.715 infecciones SARS-CoV-2 en Espana, 54.486 en Madrid, y el 21,4% eran trabajadores de la salud. El objetivo del estudio es determinar la prevalencia serologica de infeccion SARS-CoV-2 en trabajadores de un hospital monografico pediatrico. Metodo Del 13 al 30 de abril, 1.523 trabajadores fueron convocados a realizar un test serologico (All Test®) frente a SARS-CoV-2 y respondieron un cuestionario con informacion demografica, clinico-epidemiologica y de exposicion a COVID-19. Resultados Mil doscientos noventa y dos (84,8%) fueron estudiados. La prevalencia serologica (IgM y/o IgG+) a SARS-CoV-2 fue del 17,2% (222/1.292) y del 15,5% (201/1.292) considerando IgG positiva. La edad media fue 44 ± 13 anos, el 73% eran mujeres. El 33,8% (75/222) fueron asintomaticos. Tenian rRT-PCR positiva previa 81. El 14% (32/222) contacto familiar. Conclusion La prevalencia serologica SARS-CoV-2 en los trabajadores de un hospital pediatrico fue mayor que en la poblacion general. Muchos pasaron una infeccion inadvertida.

BACKGROUND Chronic hepatitis B (CHB) infection remains a significant public health issue for Indigenous Australians, in particular for remote communities. AIM This study aimed to evaluate the spectrum of hepatitis B virus (HBV) care provided to a remote Aboriginal community. Measures studied included screening, seroprevalence, vaccination rates and efficacy, and HCC risk and surveillance adherence. METHODS A retrospective audit of HBV care received by all permanent residents currently attending a remote Aboriginal Health service. This study was endorsed by both the local Aboriginal Health service and the Aboriginal Health Council of South Australia. RESULTS A total of 208 patients attended the clinic, of whom 52% (109) were screened for HBV. Of these, 12% (13) had CHB and 20% (22) had evidence of past infection. Similarly, of the 208 attending patients, complete vaccination was documented in 48% (99). Of the 33 patients with post-vaccination serology, 24% (8) had sub-therapeutic (

Background Patients with rheumatic diseases have been considered at risk of COVID-19. A significant percentage of infections in children are asymptomatic or mild and can go unnoticed. This study aims to describe the seroprevalence of SARS-CoV-2 in a cohort of children with rheumatic diseases and assess possible risk factors. Methods: A cross-sectional study was performed in a pediatric rheumatology unit from a reference hospital in Madrid, from September 2020 to February 2021. Serology of SARS-CoV-2 was performed at the same time as their routine laboratory tests, and a specific questionnaire was completed by parents. Demographics, treatment and disease activity from laboratory-confirmed COVID-19 patients were compared to the data of patients without laboratory-confirmed COVID-19.Findings A total of 105 children were included. SARS-CoV-2 infection was demonstrated in 27 patients (25.7%): 6 PCR and 21 positive IgG serology. The mean age was 11.8 years , and the majority of the patients were females (72.4%). Most of the children were diagnosed with juvenile idiopathic arthritis (JIA) (70.3%; 19/27), followed by PFAPA (11.1%; 3/27). Immunosuppresive treatment was given in 88% of cases (24/27). Overall, 44.4% (12/27) of infected patients were asymptomatic. Three patients required hospital admission because of COVID-19, however none of them required oxygen supplementation. A total of 66.7% (18/27) of patients did not require any treatment or medical assistance. The seroprevalence in our cohort was 20% in contrast to the 7.7% population seroprevalence observed during the same study period in Spanish children. SARS-CoV-2 confirmed children with positive IgG or PCR were less frequently in remission (52% vs 72%; p 0.014). Moderate disease activity and treatment with oral corticosteroids were associated with higher risk for COVID-19 (OR 5.05; CI 95%: 1.56 - 16.3 and OR 4.2; CI 95%: 1.26 - 13.9 respectively). Conclusions In a cohort of pediatric patients with rheumatic disease and immunosuppressive therapy, moderate disease activity and oral corticosteroids were associated with COVID-19 positive patients. Seroprevalence was significantly higher compared to the same age healthy population. The clinical manifestations were mild and there were no severe infections among the patients.

Background & Aims Helicobacter pylori infection is the primary known risk factor for gastric cancer. Despite the global decline in H. pylori prevalence, this infection remains a major public health concern in developing areas, including Latin America. Our study aimed to determine H. pylori seroprevalence and identified its determinants among Hispanics/Latinos living in the United States (U.S.). Methods The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is a population-based sample of self-identified Hispanics/Latinos (n = 16,144) in four U.S. communities, aged 18 to 74 years, recruited from randomly selected households using a stratified two-stage area probability sample design based on sampling households within sampled census block groups weighted for differential response rates. Anti-H. pylori immunoglobulin G antibodies were measured by an enzyme-linked immunosorbent assay using plasma samples. We calculated adjusted seroprevalence (i.e., predicted margins) from multivariable logistic regression models. Results The overall weighted H. pylori seroprevalence was 57% among HCHS/SOL participants, with 38% and 62% seropositivity among U.S.-born and non-U.S.-born individuals, respectively. Age-adjusted prevalence varied by self-reported Hispanic/Latino background, ranging from 47% in Puerto Rican to 72% in Central American backgrounds. Adjusted H. pylori seroprevalence was higher in the following groups: older age, male sex, lower education, non-U.S. born status, smoking, greater number of missing teeth, fewer doctor visits, lower ferritin level, and hepatitis A seropositivity. Conclusions H. pylori seroprevalence in Hispanics/Latinos remains high and differed significantly by Hispanic/Latino background. H. pylori seropositivity is strongly associated with poor socioeconomic conditions. These findings highlight the ongoing importance of this bacterial infection in the U.S.

Background The detection of islet autoantibodies is essential for the accurate classification and diagnosis of diabetes mellitus (DM). The islet autoantibody distribution varies by age. However, screening strategies for DM patients with different onset ages remain lacking. Methods This cross-sectional study included 17 536 DM patients from 46 medical centers across China. The seroprevalence of glutamic acid decarboxylase autoantibody (GADA), insulinoma-associated-2 autoantibody (IA-2A), zinc transporter 8 autoantibody (ZnT8A) and insulin autoantibody (IAA) was determined in younger and older patients with type 1 DM (T1DM) (n=287 and 285, respectively), younger and older patients with latent autoimmune diabetes (LAD) (n=140 and 121, respectively), and younger and older patients with type 2 DM (T2DM) (n=200 in each group). Results The cutoff age between younger and older patients was 35 years using restricted cubic spline method (n = 17 536, adjusted R2 = 0.97, residual standard error = 1.32; P < 0.001). The seroprevalence rates of four islet autoantibodies were higher in patients aged 15-35 years than in those ≥ 35 years (GADA: 17% vs. 5.6%, IA-2A: 8.5% vs. 1.3%, ZnT8A: 6.3% vs. 2.3%, IAA: 2.2% vs. 1.0%). The prevalence of ZnT8A was higher in LAD patients than in T1DM patients, especially in older LAD patients. The results indicated that ZnT8A detection can increase the detection rate of older LAD patients from 70.2% (based on GADA detection alone) to 91.7%. Conclusions In patients stratified according to the cutoff age of 35 years, the optimal detection sequence should be GADA, IA-2A, and ZnT8A in younger patients and GADA, ZnT8A, and IA-2A in older patients, so as to reduce the screening cost while improving the detection rate. Particularly, the ZnT8A test is recommended in older patients to avoid a missed LAD diagnosis.

Objectives. To characterize statewide seroprevalence and point prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Rhode Island. Methods. We conducted a cross-sectional survey of randomly selected households across Rhode Island in May 2020. Antibody-based and polymerase chain reaction (PCR)–based tests for SARS-CoV-2 were offered. Hispanics/Latinos and African Americans/Blacks were oversampled to ensure adequate representation. Seroprevalence estimations accounted for test sensitivity and specificity and were compared according to age, race/ethnicity, gender, housing environment, and transportation mode. Results. Overall, 1043 individuals from 554 households were tested (1032 antibody tests, 988 PCR tests). The estimated seroprevalence of SARS-CoV-2 antibodies was 2.1% (95% credible interval [CI] = 0.6, 4.1). Seroprevalence was 7.5% (95% CI = 1.3, 17.5) among Hispanics/Latinos, 3.8% (95% CI = 0.0, 15.0) among African Americans/Blacks, and 0.8% (95% CI = 0.0, 2.4) among non-Hispanic Whites. Overall PCR-based prevalence was 1.5% (95% CI = 0.5, 3.1). Conclusions. Rhode Island had low seroprevalence relative to other settings, but seroprevalence was substantially higher among African Americans/Blacks and Hispanics/Latinos. Rhode Island sits along the highly populated northeast corridor, making our findings broadly relevant to this region of the country. Continued monitoring via population-based sampling is needed to quantify these impacts going forward.

OBJECTIVES Since 1991 hepatitis B vaccination has been mandatory for all newborns in Italy. The aim of the study was to verify the long-term seroprevalence and the efficacy of hepatitis B vaccination in medical students of the University of Siena. MATERIAL AND METHODS A cross-sectional observational study was conducted on a population of 850 medical students of the University of Siena (322 males and 528 females, mean age: 23 years) by obtaining from the medical reports the serological analysis data for the total anti-hepatitis B antibodies (HBsAb) and information on hepatitis B vaccination (number of vaccine doses, age at the first vaccination, time since the final vaccination dose, country of origin). Raw odds ratios (ORs) and 95% confidence intervals (CIs) were initially calculated to evaluate the association between 2 variables. The adjusted ORs were then calculated using a multivariate logistic regression model to study the association between the variables and the possible confounding factors. RESULTS Overall, 593 students (69.76%) were immunized against hepatitis B, while 257 (30.24%) had HBsAb antibody titer

Background: Tokyo, the capital of Japan, is a densely populated city of >13 million people, so the population is at high risk of epidemic severe acute respiratory coronavirus 2 (SARS-CoV-2) infection. A serologic survey of anti–SARS-CoV-2 IgG would provide valuable data for assessing the city’s SARS-CoV-2 infection status. Therefore, this cross-sectional study estimated the anti–SARS-CoV-2 IgG seroprevalence in Tokyo. Methods: Leftover serum of 23,234 hospital visitors was tested for antibodies against SARS-CoV-2 using an iFlash 3000 chemiluminescence immunoassay analyzer (Shenzhen YHLO Biotech, Shenzhen, China) with an iFlash–SARS-CoV-2 IgG kit (YHLO) and iFlash–SARS-CoV-2 IgG-S1 kit (YHLO). Serum samples with a positive result (≥10 AU/mL) in either of these assays were considered seropositive for anti–SARS-CoV-2 IgG. Participants were randomly selected from patients visiting 14 Tokyo hospitals between September 1, 2020 and March 31, 2021. No participants were diagnosed with coronavirus disease 2019 (COVID-19), and none exhibited COVID-19-related symptoms at the time of blood collection. Results: The overall anti–SARS-CoV-2 IgG seroprevalence among all participants was 1.83% (95% confidence interval [CI], 1.66–2.01%). The seroprevalence in March 2021, the most recent month of this study, was 2.70% (95% CI, 2.16–3.34%). After adjusting for population age, sex, and region, the estimated seroprevalence in Tokyo was 3.40%, indicating that 470,778 individuals had a history of SARS-CoV-2 infection. Conclusions: The estimated number of individuals in Tokyo with a history of SARS-CoV-2 infection was 3.9-fold higher than the number of confirmed cases. Our study enhances understanding of the SARS-CoV-2 epidemic in Tokyo.

Several Zika virus (ZIKV) seroprevalence studies have been conducted in Africa, Asia, Oceania, the Americas, and the Caribbean. However, studies on ZIKV seroprevalence are limited in Malaysia though several studies have shown that the disease is endemic in the Malaysian state of Sabah. To evaluate the seroprevalence of ZIKV infection, 818 serum samples were collected from febrile patients and healthy blood donors from the Kudat and Kota Kinabalu districts in Sabah from 2017 to 2018. They were screened for ZIKV infection by IgM and IgG ELISA, and positive ZIKV IgM samples were subjected to a 90% neutralization test for confirmation. Twenty-four (6% [95% CI 4 to 8]) confirmed and two (0.5% [95% CI 0.13 to 1.8]) probable ZIKV infections were detected among 400 febrile illness patients. Of 418 healthy blood donor samples, six (1.4% [95% CI 0.65 to 3]) were determined as confirmed ZIKV infections and six (1.4% [95% CI 0.65 to 3]) indicated probable ZIKV infection. This is the first study on the seroprevalence of ZIKV infections among patients and healthy blood donors in Sabah. Compared with previous studies in Malaysia, this study shows that the incidence of ZIKV infection has increased. It also suggests that a sero-surveillance system is essential to determine the circulation of ZIKV in Sabah, Malaysia.

Background: In Yemen; initial surveillance of COVID-19 focused primarily on patients with symptoms or severe disease, and, as such, the full spectrum of the disease, are not clear that make the epidemiology of COVID-19 is uncertain. To the best of our knowledge, this is the first seroprevalence study done in Yemen to measure the seroprevalence of anti-SARS-CoV-2 antibodies in the general population by sex and age group in Aden, Yemen. Methods: It is a one-time cross-sectional investigation among 2000 participants from all age groups from four districts in Aden at southern Yemen. A multi-stage sampling method used. Data collected by using a well-structured questionnaire and blood sample were collected. Healgen COVID-19 IgG/IgM Rapid Test Cassette was used in all participants. All positive RDT and 14% of the negative RDTs underwent ELISA test (WANTAI SARS-CoV-2 Ab Elisa Kit). Results: A 549 out of 2001 participants were RDT positive and proved by ELISA giving the prevalence of COVID-19 infection to 27·4% and specifically the prevalence of IgG was 25%. The prevalence of asymptomatic COVID-19 infection in all the study group was 7·9%. The highest prevalence was observed in Al-Mansurah district (33·4%). Regarding socio-demographic factors females, housewives and history of contact with COVID-19 patients have significant higher prevalence rates (32%, 31% and 39% respectively). Interpretation: high prevalence of SARS-CoV-2 antibodies was reported. Household contacts are the main factors for transmission. Enhancing population immunity is recommended by introducing COVID-19 vaccine. Funding: The study was funded from WHO/ EMRO. Aden Office Declaration of Interest: None to declare. Ethical Approval: This study was approved by the University of Yemen.

Background Meningococcal serogroup C (MenC) vaccination was introduced for 14-month-olds in the Netherlands in 2002, alongside a mass campaign for 1–18 year-olds. Due to an outbreak of serogroup W disease, MenC vaccination was replaced for MenACWY vaccination in 2018, next to introduction of a booster at 14 years of age and a catch-up campaign for 14–18 year-olds. We assessed meningococcal ACWY antibodies across the Dutch population in 2016/17 and 2020. Methods In a nationwide cross-sectional serosurvey in 2016/17, sera from participants aged 0–89 years (n = 6886) were tested for MenACWY-polysaccharide-specific (PS) serum IgG concentrations, and functional MenACWY antibody titers were determined in subsets. Moreover, longitudinal samples collected in 2020 (n = 1782) were measured for MenACWY-PS serum IgG concentrations. Results MenC antibody levels were low, except in recently vaccinated 14–23 month-olds and individuals who were vaccinated as teenagers in 2002, with seroprevalence of 59% and 20–46%, respectively. Meningococcal AWY antibody levels were overall low both in 2016/17 and in 2020. Naturally-acquired MenW immunity was limited in 2020 despite the recent serogroup W outbreak. Conclusions This study demonstrates waning of MenC immunity 15 years after a mass campaign in the Netherlands. Furthermore, it highlights the lack of meningococcal AWY immunity across the population and underlines the importance of the recently introduced MenACWY (booster) vaccination.

Background Gastric acid-suppressive therapy has been suggested to increase the risk for intestinal carriage of MDR Enterobacterales, but there is scarce community-based evidence substantiating this risk. Objectives To investigate if acid-suppressant use is associated with a risk of intestinal carriage of ESBL and carbapenemase-producing Enterobacterales (ESBL-E) in the open population, and to assess possible modifying factors. Methods Within the framework of a nationwide seroprevalence study, we identified a population-based cross-sectional cohort comprising 2746 adults (≥18 years), who provided stool specimens between February 2016 and June 2017. Specimens were tested by phenotypic assays and confirmatory genotype analysis to detect carriage of ESBL-E. Covariate data were extracted from self-administered questionnaires. ORs and 95% CIs were estimated using multivariable multilevel logistic regression, controlling for confounders informed by directed acyclic graphs. Results Among 2746 participants, 316 (11.5%) used acid suppressants; the prevalence of ESBL-E carriage was 7.4% (95% CI, 6.1%–8.6%). Current use of acid suppressants was not associated with ESBL-E carriage (adjusted OR [aOR], 1.05; 95% CI, 0.64–1.74); lifestyle and comorbidity did not modify this association. A higher BMI (≥25 kg/m2) (aOR, 1.42 [95% CI, 1.02–1.98]), non-Western ethnic origin (aOR, 1.96 [95% CI, 1.34–2.87]), travel to Eastern-Mediterranean, Western-Pacific or South-East Asia regions (aOR, 3.16 [95% CI, 1.71–5.83]) were associated with ESBL-E carriage. Sensitivity analyses confirmed these results; spline analysis supported a BMI-associated risk. Conclusions In this open population study, current use of acid suppressants was not associated with ESBL-E carriage. Travel to high-endemic regions and non-Western ethnicity were confirmed as risk factors, while a higher BMI emerged as a potential new risk for ESBL-E carriage.

Background Improved understanding of Bartonella spp. serology in dogs may aid clinical decision making. Objective Describe demographic and geographic patterns of Bartonella spp. seroreactivity in dogs, and describe hematologic and serum biochemical abnormalities in Bartonella spp. seroreactive and nonseroreactive dogs. Animals Serum samples from 5957 dogs in the United States, previously submitted to IDEXX Reference Laboratories. Methods Serum was tested using 3 indirect ELISAs for B. henselae, B. vinsonii subsp. berkhoffii, and B. koehlerae. Complete blood count and serum biochemistry panel results were reviewed retrospectively. Results Overall, 6.1% of dogs were Bartonella spp. seroreactive. Toy breeds were less likely to be seroreactive (3.9%) than mixed breeds (7.5%; adjusted odds ratio [aOR], 0.48; 95% confidence interval [CI], 0.32‐0.72), and dogs

Background Seroprevalence studies of coronavirus disease 2019 (COVID-19) cases, including asymptomatic and past infections, are important to estimate the scale of the disease outbreak and to establish quarantine measures. We evaluated the clinical performance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays available in Korea for use in seroprevalence studies. Methods The sensitivity, specificity, cross-reactivity, and interference of five SARS-CoV-2 antibody assays were evaluated using the following: 398 serum samples from confirmed COVID-19 patients, 510 negative control samples from before 2018 (pre-pandemic), 163 serum samples from patients with SARS, Middle East respiratory syndrome (MERS), and other viral infections, and five samples for the interference study. Results The sensitivities of the five assays ranged from 92.2% to 98%, and their specificities, including cross-reactivity and interference, ranged from 97.5% to 100%. The agreement rates were excellent (kappa >0.9). Adjustment of the cutoff values could be considered through ROC curve analysis. The positive predictive values of the individual assays varied from 3.5% to 100% at a 0.1% prevalence but were as high as ≥95% when two assays were combined. Conclusions The prevalence of COVID-19 in Korea is considered to be exceptionally low at present; thus, we recommend using a combination of two or more SARS-CoV-2 antibody assays rather than a single assay. These results could help select SARS-CoV-2 antibody assays for COVID-19 seroprevalence studies in Korea.

Purpose The present study was undertaken with the objective to study the common etiology of Viral Haemorrhagic Fever (VHF) among patients attending tertiary health care centre in NE India and also to study the clinico-demographic profile of such patients. The agents of VHF included in the study were dengue, chikungunya and Crimean Congo haemorrhagic fever (CCHF) virus. The inclusion of CCHF was based on evidence of seroprevalence in livestock (bovine, sheep and goat) in various North Eastern states. Materials and methods Serum samples were collected from 51 suspected VHF patients. MAC-ELISA was done to detect dengue and chikungunya specific IgM antibody. The samples were also tested by real-time RT-PCR for detection of dengue, chikungunya and CCHF specific nucleic acid. The laboratory and clinico-demographic profile of these patients were noted in detail. Results Serum samples of 16 of 51 suspected cases were confirmed to be suffering from VHF. Among these confirmed cases, 12 were diagnosed with dengue haemorrhagic fever, one was diagnosed with chikungunya and three were diagnosed with dengue-chikungunya co-infection. Based on severity, DHF was further classified into- DHF I- (4,26.6%), DHF II (6,40%), DHF III (3,20%) and DHF IV (2,13.3%). There was no CCHFV infection detected in our study. Retro-orbital pain (P ​= ​0.02) and haematocrit level (P ​= ​0.03) were found to be statistically significant. Conclusions This study reiterates the fact that CCHF virus infection is still probably absent in human population of NE India and haemorrhagic symptoms, though rare maybe one of the atypical manifestations of chikungunya infection.

Purpose Amidst the on-going SARS-CoV-2 pandemic, healthcare workers have been at a greater risk of disease exposure as they are working in environments chiefly involved in the COVID-19 patient care since March 2020. SARS-CoV-2 antibody testing can prove to be a valuable tool for better understanding of prevalence of disease exposure in this population. Therefore, we conducted this study to grasp the sero-prevalence of COVID-19 antibodies in our hospital to better comprehend the duration of IgG response. Materials & methods This was a longitudinal study involving 305 healthcare workers at Rajiv Gandhi Super Speciality Hospital spanning over a period of four months starting from October 2020 to January 2021. Serum samples were obtained from the study group taken as Day 0 of the study and were screened for the presence of SARS-CoV-2 IgG antibodies using semi-quantitive enzyme linked immunoassay technology from ERBAlisa (India). The Antibody Index was determined. Those showing reactive in the screening test were further followed up on a monthly basis till January 2021 for serial antibody testing. Result The overall seroprevalence for IgG response among the workers was found to be 21.96%. Seropositivity rate was observed to be significantly higher in those having a history of RT-PCR confirmed COVID-19 infection (45.09%) CONCLUSION: Our study demonstrated that healthcare workers have a higher sero-prevalence. Our study also demonstrated that the antibodies developed following COVID-19 infection had a waning effect of protective response following infection.

Background/Aims: Data on the immunoprotective status against measles, mumps, rubella, varicella zoster virus (VZV), hepatitis A virus (HAV), and Epstein-Barr virus (EBV) infection in patients with inflammatory bowel disease (IBD) are still lacking. Therefore, we investigated the seropositivity rates for viral infectious diseases and the associated factors in Korean patients with IBD.Methods: In this retrospective cohort study, serum immunoglobulin G antibody positivity rates against measles virus, mumps virus, rubella virus, VZV, HAV, and EBV viral capsid antigen (VCA) were measured in patients with Crohn’s disease or ulcerative colitis (UC) who first visited the IBD clinic. Seropositivity rates and their associated factors were analyzed.Results: Between January 2016 and December 2018, 263 patients were enrolled (male, 167 [67.3%]; UC, 134 [50.9%]). The median age at serological test was 30 years (interquartile range, 22 to 46). The seropositivity rates were 84.0%, 85.2%, 66.5%, 87.4%, 50.0%, and 93.7% for measles, mumps, rubella, VZV, HAV, and EBV, respectively. Younger age at serological test was associated with seronegative status for measles (adjusted odds ratio [aOR], 0.92; 95% confidence interval [CI], 0.88 to 0.96), VZV (aOR, 0.83; 95% CI, 0.74 to 0.93), and HAV (aOR, 0.93; 95% CI, 0.91 to 0.95). Furthermore, IBD type-UC was associated with seronegative status against VZV (aOR, 0.33; 95% CI, 0.11 to 0.99).Conclusions: Seropositivity rates for common viral infectious diseases in Korean patients with IBD were similar to those of the general population. In the younger age group, protective immunity against measles, VZV, and HAV is required, with proper vaccination, as necessary.

During the course of COVID-19 pandemic, a wide range of scientific projects was implemented worldwide, including studies focusing on infection fatality rate (IFR). The value of IFR depends on the number of COVID-19 deaths in a population in a given period and the number of infected people in this population, usually provided by seropepidemiological studies (anti-SARS-CoV-2 IgG in the case of COVID-19). The objective of our study was to estimate IFR in the course of COVID-19 pandemic in 2020, in the general population of Upper Silesia Metropolitan Area (USMA).The seroepidemiological study was conducted in October-November 2020. Among randomly selected inhabitants of Katowice, Gliwice, and Sosnowiec (N = 1167), the presence of SARS-CoV-2 virus infection was assessed based on a positive IgG test result performed with the ELISA method. Data on deaths due to COVID-19 were obtained from the Registry Offices of each city. The infection fatality rate was calculated using the formula IFR (%) = [number of deaths/number of infected] × 100.Results of our study showed the prevalence of infection at 11.4% (95% CI: 9.5-13.2). In three examined towns, in the period January-November 2020, there was a total of 516 COVID-19 deaths. The resulting crude IFR was 0.65% (95% CI: 0.56-0.78). The IgG test had 88% sensitivity and 99% specificity and these figures were used to adjust IFR. The adjusted IFR value was similar to the crude value: IFR = 0.62% (95% CI: 0.53-0.74).The value of IFR estimated for the USMA population was similar to average values obtained in other countries and can be used as the background for monitoring the course and impact of COVID-19 pandemic in the Upper Silesian Industrial Area. Med Pr. 2021;72(6):671-6.W trakcie pandemii COVID-19 wszczęto w skali globalnej szerokie spektrum badań, w tym także ukierunkowanych na oszacowanie wskaźnika śmiertelności infekcji (Badanie seroepidemiologiczne przeprowadzono w październiku i listopadzie 2020 r. Wśród losowo wybranych mieszkańców Katowic, Gliwic i Sosnowca (N = 1167) oceniano obecność zakażenia wirusem SARS-CoV-2 na podstawie dodatniego wyniku testu IgG wykonanego metodą ELISA. Dane o zgonach z powodu COVID-19 uzyskano z Urzędów Stanu Cywilnego każdego z miast. Wskaźnik śmiertelności infekcji obliczono, stosując formułę: IFR (%) = (liczba zgonów / liczba zakażonych) × 100.Wyniki badania potwierdziły obecność przeciwciał anty-SARS-CoV-2 (klasa IgG) na poziomie 11,4% (95% CI: 9,5–13,2). Do listopada 2020 r. w populacji ww. miast zarejestrowano 516 zgonów, a tym samym surowy współczynnik IFR wyniósł 0,65% (95% CI: 0,56–0,78). Test diagnostyczny (IgG) odznaczał się czułością na poziomie 88% i swoistością wynoszącą 99%. Parametry te pozwoliły na oszacowanie skorygowanej pod względem trafności diagnostycznej testu wartości IFR. Skorygowany IFR miał podobną wartość: 0,62% (95% CI: 0,53–0,74).Oszacowana dla populacji AG wartość IFR jest zbliżona do przeciętnych poziomów obserwowanych w innych państwach i stanowi podstawę monitorowania przebiegu i skutków pandemii COVID-19 w tym regionie. Med. Pr. 2021;72(6):671–676.

Objective:To describe the cumulative seroprevalence of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) antibodies during the coronavirus disease 2019 (COVID-19) pandemic among employees of a large pediatric healthcare system.Design, setting, and participants:Prospective observational cohort study open to adult employees at the Children’s Hospital of Philadelphia, conducted April 20–December 17, 2020.Methods:Employees were recruited starting with high-risk exposure groups, utilizing e-mails, flyers, and announcements at virtual town hall meetings. At baseline, 1 month, 2 months, and 6 months, participants reported occupational and community exposures and gave a blood sample for SARS-CoV-2 antibody measurement by enzyme-linked immunosorbent assays (ELISAs). A post hoc Cox proportional hazards regression model was performed to identify factors associated with increased risk for seropositivity.Results:In total, 1,740 employees were enrolled. At 6 months, the cumulative seroprevalence was 5.3%, which was below estimated community point seroprevalence. Seroprevalence was 5.8% among employees who provided direct care and was 3.4% among employees who did not perform direct patient care. Most participants who were seropositive at baseline remained positive at follow-up assessments. In a post hoc analysis, direct patient care (hazard ratio [HR], 1.95; 95% confidence interval [CI], 1.03–3.68), Black race (HR, 2.70; 95% CI, 1.24–5.87), and exposure to a confirmed case in a nonhealthcare setting (HR, 4.32; 95% CI, 2.71–6.88) were associated with statistically significant increased risk for seropositivity.Conclusions:Employee SARS-CoV-2 seroprevalence rates remained below the point-prevalence rates of the surrounding community. Provision of direct patient care, Black race, and exposure to a confirmed case in a nonhealthcare setting conferred increased risk. These data can inform occupational protection measures to maximize protection of employees within the workplace during future COVID-19 waves or other epidemics.

Resolving the role of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission in households with members from different generations is crucial for containing the current pandemic. We conducted a large-scale, multicenter, cross-sectional seroepidemiologic household transmission study in southwest Germany during May 11–August 1, 2020. We included 1,625 study participants from 405 households that each had ≥1 child and 1 reverse transcription PCR–confirmed SARS-CoV-2–infected index case-patient. The overall secondary attack rate was 31.6% and was significantly higher in exposed adults (37.5%) than in children (24.6%–29.2%; p = 60 years of age (72.9%; p = 0.039). Other risk factors for infectiousness of the index case-patient were SARS-CoV-2–seropositivity (odds ratio [OR] 27.8, 95% CI 8.26–93.5), fever (OR 1.93, 95% CI 1.14–3.31), and cough (OR 2.07, 95% CI 1.21–3.53). Secondary infections in household contacts generate a substantial disease burden.

Although coxsackievirus A21 (CV-A21) has been associated with acute respiratory infection (ARI) as well as poliomyelitis-like paralysis, reports of CV-A21 detection have been quite limited both globally and in Japan. CV-A21 strains were isolated from five sporadic pediatric cases with ARI in 2019 in Yamagata, Japan. Neutralizing antibodies (NT Abs) were then measured against CV-A21 using sera collected in 1976, 1985, 1999, 2009, and 2019 in Yamagata, to clarify the longitudinal epidemiology of CV-A21. The total Ab-positive rate in each year was 15.2% (35/233), 10.7% (30/281), 14.3% (28/196), 3.1% (7/236), and 1.3% (3/226), respectively. Ab-positive rates generally increased with age, especially between 1976 and 1999. Among the total Ab-positive cases, the Ab titers were relatively low; 50 cases belonged to the 1:8-1:16, 40 to 1:32-1:64, 12 to 1:128-1:256 and 1 to 1:1024< groups, respectively. No Ab-positive cases under the age of 10 were observed in any of the years analyzed. In conclusion, this study and previous works suggested that CV-A21 is a unique enterovirus, which is not transmitted readily among young children but causes sporadic ARI cases mainly among those ≥ 15 years of age in the community. This article is protected by copyright. All rights reserved.

Zoonotic orthopoxvirus outbreaks have occurred repeatedly worldwide, including monkeypox in Africa and the United States, cowpox in Europe, camelpox in the Middle East and India, buffalopox in India, vaccinia in South America, and novel emerging orthopoxvirus infections in the United States, Europe, Asia, and South America. Waning smallpox immunity may increase the potential for animal-to-human transmission followed by further community transmission person-to-person (as demonstrated by monkeypox and buffalopox outbreaks) and by contact with fomites (as demonstrated by camelpox, cowpox, and, possibly, Alaskapox). The objectives of this review are to describe the disease ecology, epidemiology, clinical manifestations, prevention, and control of human infections with animal orthopoxviruses and to discuss the association with diminished population herd immunity formerly induced by vaccinia vaccination against smallpox. Internet search engines were queried with key words, and case reports, case series, seroprevalence studies, and epidemiologic investigations were found for review.

Poor responses to mRNA COVID-19 vaccine have been reported after 2 vaccine injections in kidney transplant recipients (KTRs) treated with belatacept. We analyzed the humoral response in belatacept-treated KTRs without a history of SARS-CoV-2 infection who received three injections of BNT162b2-mRNA COVID-19 vaccine. We also investigated vaccine immunogenicity in belatacept-treated KTRs with prior COVID-19 and characterized symptomatic COVID-19 infections after the vaccine in belatacept-treated KTRs. Among the 62 belatacept-treated KTRs (36 [58%] males), the median age (63.5 years IQR [51-72]), without COVID-19 history, only four patients (6.4%) developed anti-SARS-CoV-2 IgG with low antibody titers (median 209, IQR [20-409] AU/ml). 71% were treated with mycophenolic acid and 100% with steroids in association with belatacept. In contrast, in all the 5 KTRs with prior COVID-19 history, mRNA vaccine induced a strong antibody response with high antibody titers (median 10 769 AU/ml, IQR [6410-20 069]) after two injections. Seroprevalence after three-vaccine doses in 35 non-belatacept-treated KTRs was 37.1%. Twelve KTRs developed symptomatic COVID-19 after vaccination, including severe forms (50% of mortality). Breakthrough COVID-19 occurred in 5% of fully vaccinated patients. Administration of a third dose of BNT162b2 mRNA COVID-19 vaccine did not improve immunogenicity in KTRs treated with belatacept without prior COVID-19. Other strategies aiming to improve patient protection are needed.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections may be underestimated because of limited access to testing. We measured SARS-CoV-2 seroprevalence in South Africa every 2 months during July 2020–March 2021 in randomly selected household cohorts in 2 communities. We compared seroprevalence to reported laboratory-confirmed infections, hospitalizations, and deaths to calculate infection–case, infection–hospitalization, and infection–fatality ratios in 2 waves of infection. Post–second wave seroprevalence ranged from 18% in the rural community children

The poultry sector in Pakistan is contributing mainly in bridging gap between demand and supply for protein. Mycoplasma gallisepticum is an emerging bacterium causing serious problems in poultry industry of Pakistan. A cross-sectional study was conducted to evaluate the M. gallisepticum load in poultry populated regions of Pakistan. Total 600 serum and 600 swab samples were collected, 200 from each broiler, layers and breeders poultry in Rawalpindi and Abbottabad districts. Serum samples were analyzed through ELISA for seroprevalence. Swabs were cultured on Frey’s medium followed by PCR and partial mgc2 gene sequencing. Results of seroprevalence of M. gallisepticum showed that layers (75%, n=150) are more positive as compared to breeders (70%, n=140) and broilers (50%, n=100). Typical colonies of the M. gallisepticum were observed in breeder (26.5%), followed by layer (21%) and broilers (9%). A total of 37.1% (n=42) samples were identified positive through PCR out of total 113 cultured based positive samples. A total of six M. gallisepticum isolates of current study showed 98-99 percent similarity with previously reported isolates on the basis of mgc2 gene partial sequencing. The M. gallisepticum was found highly prevalent in different poultry breads. Results of this study would add into basic data and provide a direction for livestock sector to strengthen a control strategy for mycoplasmosis in poultry farms. Resumo O setor avícola do Paquistão está contribuindo principalmente para preencher a lacuna entre a demanda e a oferta de proteína. Mycoplasma gallisepticum é uma bactéria emergente que causa sérios problemas na indústria avícola do Paquistão. Um estudo transversal foi conduzido para avaliar a carga de M. gallisepticum em regiões de avicultura do Paquistão. Um total de 600 amostras de soro e 600 amostras de esfregaço foi coletado, 200 de cada frango de corte, poedeiras e aves reprodutoras nos distritos de Rawalpindi e Abbottabad. Amostras de soro foram analisadas por ELISA para soroprevalência. As zaragatoas foram cultivadas em meio Frey, seguido de PCR e sequenciação parcial do gene mgc2. Os resultados da soroprevalência de M. gallisepticum mostraram que as poedeiras (75%, n = 150) são mais positivas em comparação com matrizes (70%, n = 140) e frangos de corte (50%, n = 100). Colônias típicas de M. gallisepticum foram observadas em reprodutoras (26,5%), seguidas de poedeiras (21%) e frangos de corte (9%). Um total de 37,1% (n = 42) das amostras foi identificado como positivas por PCR de um total de 113 amostras positivas baseadas em cultura. Um total de seis isolados de M. gallisepticum do estudo atual mostrou 98-99% de similaridade com isolados relatados anteriormente com base no sequenciamento parcial do gene mgc2. O M. gallisepticum foi encontrado com alta prevalência em diferentes pães de aves. Os resultados deste estudo acrescentariam dados básicos e forneceriam orientação para o setor pecuário fortalecer uma estratégia de controle da micoplasmose em granjas avícolas.

Background Acute febrile illnesses (AFIs), including dengue, scrub typhus and leptospirosis, cause significant morbidity and mortality in Southeast Asia. Serological surveillance can be used to investigate the force and distribution of infections. Dried blood spot (DBS) samples are an attractive alternative to serum because they are easier to collect and transport and require less cold storage. We conducted a pilot study to determine the feasibility of integrating serological surveillance for dengue, scrub typhus and leptospirosis into a population-representative lymphatic filariasis seroprevalence survey in Timor-Leste using DBSs. Methods A total of 272 DBSs were collected from healthy community participants. DBSs were analysed at the National Health Laboratory using commercially available enzyme-linked immunosorbent assays. To validate assays for DBSs, 20 anonymised serum samples of unknown serostatus were used to create dried serum spots (DSSs). These were analysed with optical densities compared with those of serum. Where low variance was observed (dengue assay) the published kit cut-offs for serum were applied to the analysis of DBSs. For the other assays (scrub typhus and leptospirosis), index values (IVs) were calculated and cut-offs were determined to be at 2 standard deviations (SDs) above the mean. Results Of the 272 samples analysed, 19 (7.0% [95% confidence interval {CI} 4.3 to 10.7]) were positive for dengue immunoglobulin G (IgG), 11 (4.0% [95% CI 2.1 to 7.1]) were positive for scrub typhus IgG and 16 (5.9% [95% CI 3.4 to 9.4%]) were positive for leptospira IgG. Conclusions While dengue seroprevalence was lower than in nearby countries, results represent the first evidence of scrub typhus and leptospirosis transmission in Timor-Leste. Integrated programmes of serological surveillance could greatly improve our understanding of infectious disease epidemiology in remote areas and would incur minimal additional fieldwork costs. However, when planning such studies, the choice of assays, their validation for DBSs and the laboratory infrastructure and technical expertise at the proposed location of analysis must be considered.

Health care workers (HCWs) are at the frontline for combatting the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. To describe recent or past infections, the novel development of serological assays enabled the assessment of the immune response developed in coronavirus disease (COVID-19). Here, we investigate SARS-CoV-2 seroprevalence in high-risk HCWs in a Belgian general hospital after both the first and the second waves. Three different immunoassays were used to determine immune response to SARS-CoV-2 in volunteer HCWs who worked in at least one COVID-19-dedicated ward [emergency department, intensive care unit (ICU) and internal medicine department] in our institution from 8 May 2020 to 19 May 2020 (n = 267) and from 18 January 2021 to 8 February 2021 (n = 189). Risk factors for seropositivity were also assessed using a questionnaire filled out by all participants. We report a steep increase in seroprevalence after the second wave and report a higher seropositivity in HCWs than in the general population. Furthermore, we show that ICU personnel and especially nurses exhibit a proportionally lower SARS-CoV-2 seroprevalence. This study documents the rapid increase in SARS-CoV-2 seroprevalence in highly exposed HCWs in a context of high viral circulation prior to vaccination campaigns. Most importantly, it suggests a lower occupational risk in ICU and illustrates the role of diagnostic labeling and use of personal protective equipment during the COVID-19 pandemic.

BACKGROUND Italy experienced SARS-CoV-2 spread during the second wave and the southern regions were severely affected. In this prospective study, we assessed the changes in SARS-CoV-2 seroprevalence rates in non-vaccinated blood donors to evaluate the spread of SARS-CoV-2 among healthy individuals in our geographical area. METHODS 8,183 healthy blood donors visiting the Transfusion Centre at the University Hospital "Riuniti" of Foggia (Italy) to donate blood from May 2020 to March 2021 were tested twice for anti-SARS-CoV-2 antibodies by Ortho Clinical Diagnostics VITROS® 3600 through anti-SARS-CoV-2 Total and IgG reagent kit. None of the subjects had diagnosed symptomatic COVID-19 infection, and none had received vaccination. RESULTS Overall, 516 out of 8,183 had antibodies to SARS-CoV-2 (total and IgG antibodies) (6.3%, 95% CI: 0.03-0.15%), 387 were male and 129 female. There was a significant increase of seropositive donors from May 2020 to March 2021 (p

Background Infection with the novel coronavirus SARS‐CoV‐2 induces antibodies that can be used as a proxy for COVID‐19. We present a repeated nationwide cross‐sectional study assessing the seroprevalence of SARS‐CoV‐2, the infection fatality rate (IFR), and infection hospitalization rate (IHR) during the first year of the pandemic in Norway. Methods Residual serum samples were solicited in April/May 2020 (Round 1), in July/August 2020 (Round 2) and in January 2021 (Round 3). Antibodies against SARS‐CoV‐2 were measured using a flow cytometer‐based assay. Aggregate data on confirmed cases, COVID‐19‐associated deaths and hospitalizations were obtained from the Emergency preparedness registry for COVID‐19 (Beredt C19), and the seroprevalence estimates were used to estimate IFR and IHR. Results Antibodies against SARS‐CoV‐2 were measured in 4840 samples. The estimated seroprevalence increased from 0.8% (95% credible interval [CrI] 0.4%–1.3%) after the first wave of the pandemic (Rounds 1 and 2 combined) to 3.2% (95% CrI 2.3%–4.2%) (Round 3). The IFR and IHR were higher in the first wave than in the second wave and increased with age. The IFR was 0.2% (95% CrI 0.1%–0.3%), and IHR was 0.9% (95% CrI 0.6%–1.5%) for the second wave. Conclusions The seroprevalence estimates show a cumulative increase of SARS‐CoV‐2 infections over time in the Norwegian population and suggest some under‐recording of confirmed cases. The IFR and IHR were low, corresponding to the relatively low number of COVID‐19‐associated deaths and hospitalizations in Norway. Most of the Norwegian population was still susceptible to SARS‐CoV‐2 infection after the first year of the pandemic.

Programs to eliminate trachoma as a public health problem use prevalence of the clinical sign trachomatous inflammation—follicular (TF) in 1- to 9-year-olds in endemic districts to make decisions to begin or end mass drug administration with azithromycin. Trachomatous inflammation—follicular is used as a proxy for transmission of ocular Chlamydia trachomatis infection. Long-term monitoring of previously endemic districts for recrudescence of ocular C. trachomatis infection would benefit from a simple blood test that could be integrated with other public health programs. In this study, we evaluated multiple tests to measure antibodies against the C. trachomatis antigen Pgp3—a multiplex bead assay (MBA), an ELISA, and two versions of a lateral flow assay (LFA)—in four districts of the Amhara region of Ethiopia with varying levels of TF. Seroprevalence and seroconversion rate (SCR) results were proportional to TF prevalence by district for most tests, with the notable exception of the LFA using colloidal gold as the developing reagent. Changing the test developing reagent to black latex improved agreement between serological measures and TF prevalence and in inter-rater agreement. Seroconversion rate estimates using data derived from the LFA-gold assay were inconsistent with the shape of the age-seroprevalence curve, which did not increase in older ages. These data revealed potential complications with using SCR that will need further evaluation. Data from MBA, ELISA, and LFA with the black test line showed good agreement with each other and proportionality to TF estimates, providing further data that serology has potential utility for trachoma surveillance.

Purpose To determine the seroprevalence of SARS-CoV-2 antibodies in eye healthcare workers (EHCW) in the largest ophthalmology centre in Guatemala and factors associated with antibody positivity. Methods We conducted a cross sectional sero-survey in all the staff at the largest ophthalmology centre in Guatemala. Serum samples were collected and tested for total antibodies against SARS-CoV-2 employing Roche Elecsys Anti-SARS-CoV-2 Immunoassay. Results were reported as reactive or non-reactive. According to patient exposure the staff were divided into low risk (technicians, domestic and administrative staff) and high risk (nurses, ophthalmologists, anaesthesiologists, and optometrists). Among those with positive antibodies, they were given a survey that included demographic characteristics, COVID-19 exposure, and related symptomatology. Logistic regression was used to determine the factors associated with antibody positivity. Results On November 25th a total of 94 healthcare workers were sero-surveyed, mean age was 34.15 years (±8.41), most (57.44%) were females. Seroprevalence was 18%, the majority (77%) were in the low-risk group; while 64% at high-risk, tested negative. Those at low exposure, were five times more likely to have antibodies than those at high exposure (OR:5.69; 95% CI 1.69–19.13). Age and gender were not associated to seropositivity. Conclusions We found a similar seroprevalence of SARS-CoV-2 antibodies in EHCW to what has been reported in other healthcare groups. Seropositivity was higher among HCW with fewer patient exposure, hence the probability of community transmission.Key messagesEven though eye healthcare workers are believed to be at higher risk of infection, the prevalence of antibodies against SARS-CoV-2 in this group is comparable to what has been reported previously in other healthcare groups.

Background Refugees in Malaysia, who are afflicted by poverty, conflict and poor health, are vulnerable to a range of zoonotic infections in the deprived environmental and social conditions under which they live. Exposure to infections such as leptospirosis, for which rodents are primary hosts, is of particular concern. Methods A wellness program was conducted to determine the presence of antibodies against Leptospira (seroprevalence) in 11 refugee community schools and centers in the Klang Valley, Malaysia. A total of 433 samples were assessed for IgG and IgM antibodies against Leptospira, using enzyme-linked immunosorbent assays (ELISA). Results Overall Leptospira seroprevalence was 24.7%, with 3.0% being seropositive for anti-Leptospira IgG and 21.7% for anti-Leptospira IgM. Factors significantly associated with overall Leptospira seroprevalence included: age, ethnicity, pet ownership, knowledge of disease and awareness of disease fatality. For IgM seroprevalence, significant risk factors included sex, ethnicity, eating habits with hands, pet ownership, the presence of rats, walking in bare feet and water recreation visits. Conclusions These findings highlight the need for improvements in health and well-being among the refugee community through disease awareness programs and provision of healthy behavior programs, particularly in hygiene and sanitation through community engagement activities.

Objectives This study aims to estimate the prevalence of coronavirus disease 2019 (COVID-19) in the general population of Iran. Methods The target population was all Iranian people aged 6 years and older in the country. A stratified random sampling design was used to select 28 314 people from among the individuals registered in the electronic health record systems used in primary health care in Iran. Venous blood was taken from each participant and tested for the IgG antibody against COVID-19. The prevalence of COVID-19 was estimated at provincial and national levels after adjusting for the measurement error of the laboratory test, non-response bias and sampling design. Results Of the 28 314 Iranians selected, 11 256 (39.75%) participated in the study. Of these, 5406 (48.0%) were male and 6851 (60.9%) lived in urban areas. The mean (standard deviation) participant age was 35.89 (18.61) years. The adjusted prevalence of COVID-19 until 20 August 2020 was estimated as 14.2% (95% uncertainty interval 13.3%–15.2%), which was equal to 11 958 346 (95% CI 11 211 011–12 746 776) individuals. The adjusted prevalences of infection were 14.6%, 13.8%, 16.6%, 11.7% and 19.4% among men, women, urban population, rural population and individuals aged 60 years or more, respectively. Ardabil, Golestan and Khuzestan provinces had the highest prevalence and Alborz, Hormozgan and Kerman provinces had the lowest. Conclusions Based on the study results, a large proportion of the Iranian population had not yet been infected by COVID-19. The observance of hygienic principles and social restrictions should therefore continue until the majority of the population has been vaccinated.

Objective To perform a meta-analysis that investigates the prevalence and seroprevalence of celiac disease (CD) in Chinese general population and high-risk populations, and to summarize data from a serological survey of high-risk populations in Guangdong, China. Methods We collected data from the serological survey of high-risk populations in Guangdong, China (n = 1390) by testing serum tissue transglutaminase immunoglobulin A (tTG-IgA), deamidated gliadin peptides immunoglobulin A (DGP-IgA) and deamidated gliadin peptides immunoglobulin G (DGP-IgG), and also searched Medline, PubMed, Embase, Cochrane and 3 Chinese databases up to December 20, 2020 to estimate the pooled prevalence and seroprevalence of CD in China. Results In the serological survey, 0.94% (13/1390) individuals were positive for CD antibodies. In a meta-analysis of 18 studies, the seroprevalence of CD in Chinese general population was 0.27% (95% CI, 0.02-0.71). The seroprevalence of CD in Chinese high-risk populations was 8.34% (95% CI, 4.90-12.54), significantly higher than that in general population (OR 7.27, 95% CI, 4.06-13.04). The prevalence of biopsied-proven CD in high-risk Chinese populations was 4.44% (95% CI, 1.53-8.58). The seroprevalence of CD was varying with geographic origin, higher in Northern China than that in Southern China. Conclusions The basis for diagnosis of CD in Chinese patients should be through early case-finding by serological screening in high-risk groups; generous serological testing in patients with vague symptoms, especially in Northern Chinese.

Introduction: The effect of SARS-CoV-2 infection in patients with multiple sclerosis (MS) and the influence of disease-modifying therapies (DMT) for MS on COVID-19 are unknown. To date, patients with MS have not been shown to present greater risk of COVID-19 or more severe progression of the disease. Methods: We performed a descriptive study of patients with MS presenting SARS-CoV-2 infection diagnosed with PCR. We analysed demographic, clinical, laboratory, and treatment variables in our sample. Presence of antibodies against the virus was also determined. Results: Relapsing-remitting MS (RRMS) was the most frequent form of MS in our sample. Prognosis was unfavourable in 10.2% of patients, and was associated with older age and higher scores on the Expanded Disability Status Scale (EDSS). Seroprevalence of antibodies against SARS-CoV-2 was 83.3% in our sample. Development of antibodies was not associated with DMT, lymphocytopaenia, or any of the other variables analysed. Conclusions: The incidence of COVID-19 was slightly higher in our sample than in the general population in our province. Unfavourable prognosis was associated with older age and higher EDSS scores. DMT and lymphocytopaenia did not influence the clinical course of COVID-19. Seroprevalence of antibodies against the virus in our sample was similar to that reported for the general population with positive PCR results for the virus; the influence of specific DMTs could not be determined. Resumen: Introducción: El efecto de la infección por SARS-CoV-2 en los pacientes con esclerosis múltiple (EM) y la influencia de los tratamientos modificadores de la enfermedad (TME) es desconocida. Hasta el momento no se ha observado que los pacientes con EM tengan mayor riesgo de infección por COVID-19 ni peor curso evolutivo de la misma. Métodos: Estudio descriptivo de pacientes con EM e infección por SARS-CoV-2 diagnosticada mediante PCR. Hemos analizado variables demográficas, clínicas, de laboratorio y de tratamiento en nuestra muestra. Se ha determinado la presencia de anticuerpos frente SARS-CoV-2 en estos pacientes. Resultados: La forma de esclerosis múltiple remitente recurrente (EMRR) fue la más frecuente en los pacientes con EM e infección por COVID-19. El 10.2% presentó una evolución desfavorable, relacionada con una mayor edad y una EDSS más elevada. La seroprevalencia de anticuerpos frente a SARS-CoV-2 en nuestro estudio ha sido del 83,3%. El desarrollo de anticuerpos no está relacionado con el TME, la presencia de linfopenia u otros factores analizados. Conclusiones: La incidencia de COVID-19 ha sido ligeramente superior a la de la población general de nuestra provincia. La evolución desfavorable se ha relacionado con una mayor edad y una puntuación elevada en la EDSS. El TME y la linfopenia no se han relacionado con el curso de la infección por COVID-19. La seroprevalencia es similar a la encontrada en población general con PCR positiva, sin poder determinar la influencia de los distintos TME.

Background By August 2021, the COVID-19 pandemic has been less severe in sub-Saharan Africa than elsewhere. In Malawi, there have been three subsequent epidemic waves. We therefore aimed to describe the dynamics of SARS-CoV-2 exposure in Malawi. Methods We measured the seroprevalence of anti-SARS-CoV-2 antibodies amongst randomly selected blood transfusion donor sera in Malawi from January 2020 to July 2021 using a cross-sectional study design. In a subset, we also assessed in vitro neutralisation against the original variant (D614G WT) and the Beta variant. Results A total of 5085 samples were selected from the blood donor database, of which 4075 (80.1%) were aged 20–49 years. Of the total, 1401 were seropositive. After adjustment for assay characteristics and applying population weights, seropositivity reached peaks in October 2020 (18.5%) and May 2021 (64.9%) reflecting the first two epidemic waves. Unlike the first wave, both urban and rural areas had high seropositivity in the second wave, Balaka (rural, 66.2%, April 2021), Blantyre (urban, 75.6%, May 2021), Lilongwe (urban, 78.0%, May 2021), and Mzuzu (urban, 74.6%, April 2021). Blantyre and Mzuzu also show indications of the start of a third pandemic wave with seroprevalence picking up again in July 2021 (Blantyre, 81.7%; Mzuzu, 71.0%). More first wave sera showed in vitro neutralisation activity against the original variant (78% [7/9]) than the beta variant (22% [2/9]), while more second wave sera showed neutralisation activity against the beta variant (75% [12/16]) than the original variant (63% [10/16]). Conclusion The findings confirm extensive SARS-CoV-2 exposure in Malawi over two epidemic waves with likely poor cross-protection to reinfection from the first on the second wave. The dynamics of SARS-CoV-2 exposure will therefore need to be taken into account in the formulation of the COVID-19 vaccination policy in Malawi and across the region. Future studies should use an adequate sample size for the assessment of neutralisation activity across a panel of SARS-CoV-2 variants of concern/interest to estimate community immunity.

Summary Objectives We assessed SARS-CoV-2 infection, seroprevalence and seroconversion in students and staff when secondary schools reopened in March 2021. Methods We initiated SARS-CoV-2 surveillance in 18 secondary schools across six regions in September 2020. Participants provided nasal swabs for RT-PCR and blood samples for SARS-CoV-2 antibodies at the beginning (September 2020) and end (December 2020) of the autumn term and at the start of the spring term (March 2021). Findings In March 2021, 1895 participants (1100 students:795 staff) were tested; 5.6% (61/1094) students and 4.4% (35/792) staff had laboratory-confirmed SARS-CoV-2 infection from December 2020-March 2021. Nucleoprotein-antibody seroprevalence was 36.3% (370/1018) in students and 31.9% (245/769) in staff, while spike-antibody prevalence was 39.5% (402/1018) and 59.8% (459/769), respectively, similar to regional community seroprevalence. Between December 2020 and March 2021, 14.8% (97/656; 95%CI: 12.2–17.7) students and 10.0% (59/590; 95%CI: 7.7–12.7) staff seroconverted. Weekly seroconversion rates were similar from September to December 2020 (8.0/1000) and from December 2020 to March 2021 (7.9/1000; students: 9.3/1,000; staff: 6.3/1,000). Interpretation By March 2021, a third of secondary school students and staff had evidence of prior infection based on N-antibody seropositivity, and an additional third of staff had evidence of vaccine-induced immunity based on S-antibody seropositivity.

Background: The Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) is the cause of the Coronavirus Diseases of 2019 (COVID-19). This virus has been responsible for the global pandemic of 2020 and 2021 with over 107 million confirmed cases and over 2.3 million deaths. An important population that deserves meticulous consideration during the COVID-19 pandemic is pregnant woman; however, in many places in the world there is inadequate screening for SARS-COV-2 during pregnancy. We aimed to determine the impact of maternal and neonatal cord blood SARS-COV-2 antibodies and placental transfer ratios in a region with a low screening plan. Methods: We performed a blind study in Babahoyo, Ecuador; one of the SARS-CoV-2epicenters in South America. Blood samples were collected from 100 serum samples collected from pregnant women at the time of delivery along with corresponding neonatal cord blood. SARS-CoV-2 IgG specific antibodies were determined using a enzyme linked immunosorbent assay (ELISA) for IgG and IgM SARS-CoV-2-specific nucleocapsid and spike antigens (DiaPro, Milano, Italy Cat number COV19G.CE). Findings: We observed 32% of pregnant women to be serological positive in areas lacking an appropriate screening program. We also show data that suggests an efficient passive immunization of the fetus to SARS-CoV-2 during pregnancy. Interpretation: There is a high incidence of SARS-CoV-2 infection during pregnancy. The best prevention for protecting the mother from infection is vaccination, which, will provide the fetus and neonate with a strong protection against SARS-CoV-2 infection through passive placental transfer of SARS-CoV-2 specific antibodies. This is especially important because newborns are highly susceptible to many viral infections. Funding: NIAID 1R01AI145829-01 Declaration of Interest: None to declare. Ethical Approval: This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines. This was retrospective study done with samples sent for tests evaluation that were originally not related to this study. A consent waiver was approved since the samples were not collected for the study and the samples used were defined as dischargeable material.

We aimed to generate an unbiased estimate of the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 4 urban counties in Utah, USA. We used a multistage sampling design to randomly select community-representative participants >12 years of age. During May 4–June 30, 2020, we collected serum samples and survey responses from 8,108 persons belonging to 5,125 households. We used a qualitative chemiluminescent microparticle immunoassay to detect SARS-CoV-2 IgG in serum samples. We estimated the overall seroprevalence to be 0.8%. The estimated seroprevalence-to-case count ratio was 2.5, corresponding to a detection fraction of 40%. Only 0.2% of participants from whom we collected nasopharyngeal swab samples had SARS-CoV-2–positive reverse transcription PCR results. SARS-CoV-2 antibody prevalence during the study was low, and prevalence of PCR-positive cases was even lower. The comparatively high SARS-CoV-2 detection rate (40%) demonstrates the effectiveness of Utah’s testing strategy and public health response.

In September 2020, we tested 13,398 persons in Portugal for antibodies against severe acute respiratory syndrome coronavirus 2 by using a quota sample stratified by age and population density. We found a seroprevalence of 2.2%, 3–4 times larger than the official number of cases at the end of the first wave of the pandemic.

Sparse data exist on the complex natural immunity to SARS-CoV-2 at the population level. We applied a well-validated multiplex serology test in 5000 participants of a general population study in Catalonia in blood samples collected from end June to mid November 2020. Based on responses to fifteen isotype-antigen combinations, we detected a seroprevalence of 18.1% in adults (n = 4740), and modeled extrapolation to the general population of Catalonia indicated a 15.3% seroprevalence. Antibodies persisted up to 9 months after infection. Immune profiling of infected individuals revealed that with increasing severity of infection (asymptomatic, 1-3 symptoms, ≥ 4 symptoms, admitted to hospital/ICU), seroresponses were more robust and rich with a shift towards IgG over IgA and anti-spike over anti-nucleocapsid responses. Among seropositive participants, lower antibody levels were observed for those ≥ 60 years vs < 60 years old and smokers vs non-smokers. Overweight/obese participants vs normal weight had higher antibody levels. Adolescents (13-15 years old) (n = 260) showed a seroprevalence of 11.5%, were less likely to be tested seropositive compared to their parents and had dominant anti-spike rather than anti-nucleocapsid IgG responses. Our study provides an unbiased estimate of SARS-CoV-2 seroprevalence in Catalonia and new evidence on the durability and heterogeneity of post-infection immunity. We thank the volunteers who participate in the cohort studies, all the workers in different facilities of the Blood and Tissue Bank for sample recruitment, Jordi Chi for antigen expression and purification and Victor Moreno for data collection in MCC study. This study makes use of data generated by the GCAT-Genomes for Life. Cohort study of the Genomes of Catalonia, Fundacio IGTP. IGTP is part of the CERCA Program/Generalitat de Catalunya. GCAT is supported by Acción de Dinamización del ISCIII-MINECO and the Ministry of Health of the Generalitat of Catalunya (ADE 10/00026); the Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR) (2017-SGR 529). Full list of the investigators who contributed to the generation of the GCAT data is available from www.genomesforlife.com. LeRAgs is supported by Instituto de Salud Carlos III (PI17/01555). Beatriz Cortés is supported by ISCIII national Grant PI18/01512. Ioar Rivas is supported from the postdoctoral fellowships programme Beatriu de Pinós (2018 BP 00114), funded by the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 programme of research and innovation of the European Union under the Marie Sklodowska-Curie Grant Agreement No 801370. This work was funded by Incentius a l’Avaluació de Centres CERCA (in_CERCA); EIT HEALTH BP2020-20873-Certify.Health.; Fundació Privada Daniel Bravo Andreu; PID2019-110810RB-I00 Grant (Spanish Ministry of Science & Innovation). ISGlobal acknowledges support from the Spanish Ministry of Science and Innovation through the “Centro de Excelencia Severo Ochoa 2019–2023” Program (CEX2018-000806-S). ISGlobal and IGTP receive support from the Generalitat de Catalunya through the CERCA Program. The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Background Limitations in laboratory testing capacity undermine the ability to quantify the overall burden of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Methods We undertook a population-based serosurvey for SARS-CoV-2 infection in 26 subdistricts, Gauteng Province (population 15.9 million), South Africa, to estimate SARS-CoV-2 infection, infection fatality rate (IFR) triangulating seroprevalence, recorded COVID-19 deaths and excess-mortality data. We employed three-stage random household sampling with a selection probability proportional to the subdistrict size, stratifying the subdistrict census-sampling frame by housing type and then selecting households from selected clusters. The survey started on 4 November 2020, 8 weeks after the end of the first wave (SARS-CoV-2 nucleic acid amplification test positivity had declined to Results From 6332 individuals in 3453 households, the overall RBD IgG seroprevalence was 19.1% [95% confidence interval (CI): 18.1–20.1%] and similar in children and adults. The seroprevalence varied from 5.5% to 43.2% across subdistricts. Conservatively, there were 2 897 120 (95% CI: 2 743 907–3 056 866) SARS-CoV-2 infections, yielding an infection rate of 19 090 per 100 000 until 9 January 2021, when 330 336 COVID-19 cases were recorded. The estimated IFR using recorded COVID-19 deaths (n = 8198) was 0.28% (95% CI: 0.27–0.30) and 0.67% (95% CI: 0.64–0.71) assuming 90% of modelled natural excess deaths were due to COVID-19 (n = 21 582). Notably, 53.8% (65/122) of individuals with previous self-reported confirmed SARS-CoV-2 infection were RBD IgG seronegative. Conclusions The calculated number of SARS-CoV-2 infections was 7.8-fold greater than the recorded COVID-19 cases. The calculated SARS-CoV-2 IFR varied 2.39-fold when calculated using reported COVID-19 deaths (0.28%) compared with excess-mortality-derived COVID-19-attributable deaths (0.67%). Waning RBD IgG may have inadvertently underestimated the number of SARS-CoV-2 infections and conversely overestimated the mortality risk. Epidemic preparedness and response planning for future COVID-19 waves will need to consider the true magnitude of infections, paying close attention to excess-mortality trends rather than absolute reported COVID-19 deaths.

Objective Real-time reverse transcription-polymerase chain reaction is the gold standard for the diagnosis of COVID-19, but it is necessary to utilize other tests to determine the burden of the disease and the spread of the outbreak such as IgG-, IgM-, and IgA-based antibody detection using enzyme-linked immunosorbent assay (ELISA). Materials and Methods We developed an indirect ELISA assay to quantitatively measure the amount of COVID-19 IgG, IgM, and IgA antibodies present in patient serum, dried blood, and plasma. Results The population cutoff values for positivity were determined by receiver operating characteristic curves to be 1.23 U/mL, 23.09 U/mL, and 6.36 U/mL for IgG, IgM, and IgA, respectively. After albumin subtraction, the specificity remained >98% and the sensitivity was 95.72%, 83.47%, and 82.60%, respectively, for IgG, IgM, and IgA antibodies to the combined spike subunit 1 receptor binding domain and N proteins in serum. Plasma and dried blood spot specimens were also validated on this assay. Conclusion This assay may be used for determining the seroprevalence of SARS-CoV-2 in a population exposed to the virus or in vaccinated individuals.

Summary Background Seroepidemiological studies provide important insight into the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV‑2) in our society. We aimed to determine seropositivity of SARS-CoV‑2 antibodies and its cross-sectional correlates in a large cohort of blood donors. Methods In this observational cohort study, we tested healthy blood donors residing in Tyrol, Austria, for SARS-CoV‑2 antibodies using the Abbott SARS-CoV‑2 IgG chemiluminescent microparticle immunoassay. We estimated 95% confidence intervals (95% CI) of seroprevalences using bootstrapping and tested for differences by participant characteristics using logistic regression. Findings Between 8 June and 4 September 2020, we screened 5345 healthy individuals at local blood donor sessions (mean age 42.7 years, SD 13.5 years, 46.7% female). Overall seroprevalence was 3.1% (95% CI 2.7–3.6%, 165 cases), which is 5.1-fold higher (95% CI 4.5–6.0%) than the case number identified by the health authorities in the state-wide testing program (0.6%; 4536 out of 757,634). Seroprevalence was higher in the district Landeck (16.6%, P P = 0.043), but did not differ by gender, blood types, or medication intake. The odds ratio for seropositivity was 2.51 for participants who had travelled to Ischgl (1.49–4.21, P = 0.001), 1.39 who had travelled to other federal states (1.00–1.93, P = 0.052), and 2.41 who had travelled abroad (1.61–3.63, P P = 0.005) and taste (odds ratio = 2.76, 1.54–4.92, P = 0.001). Conclusion In summer 2020, SARS-CoV‑2 seroprevalence in Tyrolean blood donors was 3.1%. Our study revealed regional variation and associations with young age, travel history and specific symptoms.

Background. This study was conducted to evaluate the anti‐SARS‐CoV‐2 IgM and IgG antibodies among healthcare workers in Guilan. Methods. This cross-sectional study was conducted on 503 healthcare workers. Between April and May 2020, blood samples were collected from the healthcare workers of Razi Hospital in Rasht, Guilan, Iran. Enzyme-linked immunosorbent assay (ELISA) was used for the detection and quantitation of anti‐SARS‐CoV‐2 IgM/IgG antibodies by using kits made by Pishtaz Teb Company, Tehran, Iran. Results. From a total of 503 participants, the result of the anti‐SARS‐CoV‐2 IgM antibody test was positive in 28 subjects (5.6%) and the anti‐SARS‐CoV‐2 IgG antibody test was positive in171 subjects (34%). Participants in the age group of 35–54 years were significantly more likely to have a positive anti‐SARS‐CoV‐2 antibody test than the age group of 20–34 years (odds ratio = 1.53, 95% CI: 1.04–2.25, P = 0.029 ). Also, physicians were significantly more likely to have a positive antibody test than office workers (odds ratio = 1.92, 95% CI: 1.04–3.54, P = 0.037 ). The wide range of symptoms was significantly associated with the positive anti‐SARS‐CoV‐2 antibody test. The most significant association was observed between fever and a positive anti‐SARS‐CoV‐2 antibody test (odds ratio = 3.03, 95% CI: 2.06–4.44, P < 0.001 ). Conclusion. The results of the current study indicated that the seroprevalence of COVID-19 was high among healthcare workers of Guilan Province. It seems that this finding was due to the earlier exposure to COVID-19 and the lack of awareness and preparedness to deal with the pandemic in Iran, compared to other countries.

Purpose of review HHV-8-associated diseases are rare but potentially fatal in transplant recipients. Important differences exist in the distribution of HHV-8 seroprevalence, which might contribute to the lack of uniform approach to HHV-8. The aim of this review was to discuss recent updates in screening and management of HHV-8 after transplant. Recent findings Increasing attention has been given to the nonmalignant but potentially fatal inflammatory syndrome caused by HHV-8 in solid organ transplant (SOT) recipients. At-risk groups include HHV-8-IgG D+/R- transplant and HHV-8-positive recipients. Severe cases of donor-derived HHV-8 disease, mainly Kaposi sarcoma, frequently without skin involvement and some diagnosed at autopsy, highlight the need to increase clinicians' awareness, to implement effective preemptive strategies and to perform rapid diagnosis. In HSCT setting, HHV-8-associated disorders are very rare. Summary Identification of SOT recipients at risk through reliable serology is warranted and the utility of preemptive management and HHV-8-DNA monitoring should be studied. Clinicians should be aware of severe nonmalignant disorders and of early post-SOT Kaposi sarcoma cases with lymph node or transplanted organ involvement in order to provide prompt diagnosis and treatment. No screening for HHV-8 is warranted after HSCT but rapid diagnosis and reduction of immunosuppression remain fundamental.

Enterovirus D68 (EV-D68) is an emerging respiratory pathogen since the 2014 outbreak in the United States. A low level of virus circulation has been reported in Kuala Lumpur, Malaysia, in the past. However, the extent of the infection in Malaysia is not known. In the present study, we determine the seroepidemiology of EV-D68 in Kuala Lumpur, Malaysia, before and after the United States outbreak in August 2014. A luciferase-based seroneutralization test was developed using a clone-derived prototype Fermon strain carrying a nanoluciferase marker. We screened the neutralization capacity of 450 serum samples from children and adults (1-89 years old) collected between 2013 and 2015. EV-D68 seropositivity increased with age, with children aged 1-3 showing significantly lower seroprevalence compared to adults. Multivariate analysis showed that older age groups 13-49 years (odds ratio [OR] = 4.78; 95% confidence interval [CI] = 2.69-8.49; p

The epidemiology of HDV infection worldwide is obscure. Mapping the epidemiology of the infection is highly required, so, we aimed to estimate the prevalence of hepatitis D virus infection among chronic hepatitis B patients and the epidemiological characteristics in the Nile delta in Egypt. This was a prospective observational cross-sectional study including consecutive chronic hepatitis B patients in the out-patient clinics at the Egyptian Liver Research Institute and Hospital (ELRIAH) and its satellites in the Nile Delta from January 2016 until August 2018. They were recruited from patients enrolled in Educate, Test and Treat program, which was implemented in 73 Egyptian Villages. Subjects were tested by using HBsAg serological rapid diagnostic tests (RDTs), and then HBV DNA by PCR was done in HBsAg-positive cases. HDV IgG antibody testing and confirmatory HDV RNA PCR were done. Complete liver functions, abdominal ultrasonography and FibroScan were also performed. The prevalence of HDV was 3.4% using anti-delta antibody (22/631), and only 8 were positive for HDV RNA (8/22, 36.4%). Overall HDV prevalence using PCR was 8/631(1.27%). HDV-positive cases were mainly males (68.2%). Eight cases were cirrhotic (36.4%), 3 (13.6%) had HCC and 7 (31.8%) were HBeAg positive. HDV prevalence is low among chronic hepatitis B patients in the Nile delta, Egypt. Screening for HDV IgG is recommended in CHB patients who had cirrhosis, HCC or HBeAg positive.