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Background: Influenza is a contagious respiratory illness responsible for seasonal epidemics and with potential to cause pandemics. The decline in influenza-related studies published since 2018 resulted in data gaps, particularly in emerging markets. Methods: This systematic review searched for studies in six databases and gray literature sources to define the clinical burden of influenza and influenza-like illness (ILIs) and their associated sequelae among humans across emerging markets. Eligible studies were published in English, Spanish, or Chinese between January 2018 and September 2023 and conducted in Asia, the Middle East, Africa, and Latin America. Results: In total, 256 articles were included, mostly on lab-confirmed influenza infections (n = 218). Incidences of lab-confirmed influenza cases in Asia (range 540–1279 cases/100,000 persons) and Sub-Saharan Africa (range 34,100–47,800 cases/100,000 persons) were higher compared to Latin America (range 0.7–112 cases/100,000 persons) and the Middle East and North Africa (range 0.1–10 cases/100,000 persons). Proportions of lab-confirmed influenza cases and influenza-associated outcomes (i.e., hospitalization, ICU admission and death) varied widely across regions. Temporal variation in influenza trend was observed before and during the COVID-19 pandemic. Conclusions: In conclusion, influenza causes significant disease burden in emerging markets. Robust large real-world studies using a similar methodology are needed to have more accurate estimates and compare studies within age groups and regions. Continuous monitoring of influenza epidemiology is important to inform vaccine programs in emerging markets with heavy influenza disease burden. [ABSTRACT FROM AUTHOR]

A correction notice was issued for a study on severe COVID-19 outcomes in five Latin American countries in the post-vaccination era, addressing an error in reported hospitalized cases in Brazil. The study analyzed clinical profiles, hospitalization rates, mortality rates, and vaccination status of confirmed COVID-19 cases, highlighting differences in outcomes between males and age groups, as well as the impact of comorbidities and COVID-19 variants on hospitalization rates. Detailed data on COVID-19 cases, mortality rates, ICU admissions, comorbidities, and vaccination status by age group is provided for Brazil, Mexico, Colombia, Argentina, and Chile, offering insights into the pandemic's impact in different regions. The authors have made corrections to ensure the scientific accuracy of their conclusions. [Extracted from the article]

We conducted a multicountry retrospective study using data from COVID-19 national surveillance databases to analyze clinical profiles, hospitalization rates, intensive care unit (ICU) admissions, utilization of ventilatory support, and mortality rates in five Latin American countries in the context of COVID-19 vaccination implementation. We analyzed the sociodemographic characteristics, comorbidities, clinical outcomes, and vaccination status of laboratory-confirmed COVID-19 cases from January 2021 to December 2022. We calculated the yearly and quarterly hospitalization rates per 1000 confirmed COVID-19 cases and ICU admissions, use of mechanical ventilators, and mortality rates per 1000 hospitalized cases, with their corresponding 95% confidence interval (CI) of 38,852,831 confirmed COVID-19 cases. Rates of hospitalization, ICU admission, ventilatory support, and death were higher among males than among females (38.2 vs. 32.4, 148.4 vs. 117.7, 282.9 vs. 236.2, and 346.9 vs. 320.1 per 1000, respectively); higher in 2021 than in 2022 (50.7 vs. 19.9, 207.8 vs. 58.2, 441.5 vs. 114.9, and 352.5 vs. 285.2 per 1000, respectively); and in the >50 age group (range: 5.7–18.6, 20.1–71.5, 12.2–67.9, and 353.1–577.4, per 1000) than the <50 age group (range: 2.2–9.3, 5.4–33.2, 41.4–135.8, and 22–243.5 per 1000). Hypertension and diabetes mellitus were the most common comorbidities in Mexico and Colombia. Prevention and treatment strategies for these case profiles could bring benefits from a public health perspective. [ABSTRACT FROM AUTHOR]

Background Antivirals are effective in reducing hospitalisation and death in mild-to-moderate coronavirus 2019 (COVID-19) patients. We estimated the antiviral uptake of nirmatrelvir/ritonavir and molnupiravir in adult patients with a syndrome coronavirus 2 (SARS-CoV-2) infection during the Emergency Use Authorization (EUA) period in Taiwan. Methods A retrospective cohort study was conducted in Taiwan between January 2022 and December 2022. Patients aged ≥18 years with a SARS-CoV-2 infection were included from the Taipei Medical University Clinical Research Database (TMUCRD) and stratified in three risk groups according to World Health Organization criteria. Results In total, 96 398 COVID-19 patients (mean age 46.7 ± 17.7 years, 45.8% male) were included. Of these patients 69.8% were classified as low risk, 29.8% as moderate risk, and 0.4% as high risk for progression to severe COVID-19. Nirmatrelvir/ritonavir was prescribed in 5.1% of the COVID-19 patients (low risk = 1.0%, moderate risk = 14.3%, high risk = 17.6%). Molnupiravir was prescribed in 1.9% of the COVID-19 patients (low risk = 0.1%, moderate risk = 5.8%, high risk = 6.9%). Conclusions Nirmatrelvir/ritonavir and molnupiravir were poorly used in the treatment of adult COVID-19 patients in Taiwan during the pandemic in 2022, especially in moderate-to-high risk groups for progression to severe COVID-19. [ABSTRACT FROM AUTHOR]

Background Data on paediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are limited, especially from the early pandemic period. Moreover, children are not considered to be at high risk for severe outcomes of coronavirus disease 2019 (COVID-19). In this systematic review and meta-analysis, we estimated the SAR-CoV-2 positivity rate, identified risk factors, and described the severity and mortality outcomes of SARS-CoV-2 infections in children aged ≤18 years until December 2021, prior to the Omicron era. Methods We searched MEDLINE, Embase, Global Health, CINAHL, China National Knowledge Infrastructure, Wanfang, CQvip, and the World Health Organization (WHO) COVID-19 global literature databases for primary studies recruiting children aged ≤18 years with a diagnosis of SARS-CoV-2 infection confirmed either by molecular or antigen tests. We used the Joanna Briggs Institute critical appraisal tools to appraise the study quality and conducted meta-analyses using the random effects model for all outcomes except for race/ ethnicity as risk factors of SARS-CoV-2 infection. Results We included 237 studies, each reporting at least one of the study outcomes. Based on data from 117 studies, the pooled SARS-CoV-2 positivity rate was 9.30% (95% confidence interval (CI)=7.15–11.73). Having a comorbidity was identified as a risk factor for SARS-CoV-2 infection (risk ratio (RR)=1.33; 95% CI=1.04–1.71) based on data from 49 studies. Most cases in this review presented with mild disease (n=50; 52.47% (95% CI=44.03–60.84)). However, 20.70% of paediatric SARS-CoV-2 infections were hospitalised (67 studies), 7.19% required oxygen support (57 studies), 4.26% required intensive care (93 studies), and 2.92% required assisted ventilation (63 studies). The case fatality ratio (n=119) was 0.87% (95% CI=0.54–1.28), which included in-hospital and out-of-hospital deaths. Conclusions Our data showed that children were at risk for SARS-CoV-2 infections and severe outcomes in the pre-Omicron era. These findings underscore the need for effective vaccination strategies for the paediatric population to protect against the acute and long-term sequelae of COVID-19. [ABSTRACT FROM AUTHOR]

Background: COVID-19 vaccines adapted to newly emerging circulating variants are necessary to better protect the population due to the evolving nature of the SARS-CoV-2 virus. Research Design and Methods: The South African population was stratified by age and risk (defined by comorbidities such as diabetes, obesity, smoking, cancer, and asthma), and HIV status. The outcomes of different vaccination strategies based on age, risk, and HIV status were estimated using a Markov-decision tree model based on age-specific inputs derived from the literature and South African surveillance data. Results: Vaccinating older adults and those with comorbidities was estimated to avert 111,179 infections 18,281 hospitalizations, and 3,868 deaths, resulting in savings of ZAR 1,260 million (USD 67 million) and ZAR 3,205 million (USD 170 million) in direct and indirect costs, respectively. Similar results were obtained when considering strategies targeting older adults and the HIV population. Expanding vaccination to 75% of the standard-risk population prevented more infections (401%), hospitalizations (167%), and deaths (67%) and increased the direct (232%) and indirect (455%) cost savings compared to the base case. Conclusions: Implementing widespread vaccination strategies that utilize a vaccine adapted to the prevailing circulating variant in South Africa would result in significant public health and economic gains. [ABSTRACT FROM AUTHOR]

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19 has been a dynamically changing virus, requiring the development of adapted vaccines. This study estimated the potential public health impact alternative vaccination strategies for COVID-19 in Singapore. Research Design and Methods: The outcomes of alternative vaccination strategies with a future adapted vaccine were estimated using a combined Markov decision tree model. The population was stratified by high- and standard-risk. Using age-specific inputs informed by local surveillance data and published sources, the model estimated health (case numbers, hospitalizations, and deaths) and economic (medical costs and productivity losses) outcomes in different age and risk subpopulations. Results: Booster vaccination in only the elderly and high-risk subpopulation was estimated to avert 278,614 cases 21,558 hospitalizations, 239 deaths, Singapore dollars (SGD) 277 million in direct medical costs, and SGD 684 million in indirect medical costs. These benefits increased as vaccination was expanded to other subpopulations. Increasing the booster vaccination coverage to 75% of the standard-risk population averted more deaths (3%), hospitalizations (29%), infections (145%), direct costs (90%), and indirect costs (192%) compared to the base case. Conclusions: Broader vaccination strategies using an adapted booster vaccine could have substantial public health and economic impact in Singapore. [ABSTRACT FROM AUTHOR]

Vaccination against infectious disease affords direct protection from vaccine-induced immunity and additional indirect protection for unvaccinated persons. A systematic review was conducted to estimate the indirect effect of COVID-19 vaccination. From PubMed and Embase, 31 studies were included describing the impact of original wild-type COVID-19 vaccines on disease transmission or viral load. Overall, study results showed the effectiveness of COVID-19 vaccination against SARS-CoV-2 transmission (range 16–95%), regardless of vaccine type or number of doses. The effect was apparent, but less pronounced against omicron (range 24–95% for pre-omicron variants versus 16–31% for omicron). Results from viral load studies were supportive, showing SARS-CoV-2 infections in vaccinated individuals had higher Ct values, suggesting lower viral load, compared to infections among the unvaccinated. Based on these findings, well-timed vaccination programs may help reduce SARS-CoV-2 transmission—even in the omicron era. Whether better-matched vaccines can improve effectiveness against transmission in the omicron era needs further study. [ABSTRACT FROM AUTHOR]