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Background: Kyrgyzstan introduced universal hepatitis B childhood vaccination in 1999 to reduce the burden of hepatitis B. In 2016, aligned with the goal of controlling hepatitis B in the WHO European Region, a regional target of 0.5% was set for seroprevalence of hepatitis B surface antigen (HBsAg) among targeted birth cohorts. We conducted a representative nationwide serosurvey to assess the HBsAg prevalence among third-grade school children in Kyrgyzstan in 2022., Methods: We sampled numbers of children proportional to the population size and stratified the sample by region and urbanization level (urban/rural). We applied multistage cluster sampling with school classes as clusters. Identified participants in the survey were tested for HBsAg, using Enzyme-linked Immunosorbent Assay (ELISA), and positive samples confirmed with neutralization tests. Data on vaccination coverage for hepatitis B birth dose (HepB BD), including timing, and three doses of hepatitis B vaccine (HepB3) were collected from medical vaccination records. We calculated crude and weighted proportions for HBsAg seroprevalence and HepB BD and HepB3 coverage., Results: From the target sample size of 3,352 children, a total of 3,183 children (95%) participated in the survey. The majority of children were 9 or 10 years old (2,964; 93%) with almost equal numbers of girls and boys (1,606; 50% boys) and rural and urban participants (1,624; 51% urban). Five participants tested positive for HBsAg in confirmatory tests. The weighted HBsAg seroprevalence was 0.12% (95% CI 0.04-0.35%). Weighted coverage for HepB BD was 88% (95% CI 86-90%) and for HepB3 90% (95% CI 86-93%). Results from crude and weighted analysis did not differ statistically., Conclusions: Our study demonstrates the impact of a successfully implemented hepatitis B vaccination programme in Kyrgyzstan. High hepatitis B vaccination coverage has resulted in very low HBsAg seroprevalence among vaccinated birth cohorts, paving the way towards the achievement of regional hepatitis B control targets. Maintaining high vaccination uptake plus additional measures like screening of pregnant women and treatment of those infected will be key to achieve elimination of vertical transmission of hepatitis B in Kyrgyzstan., Competing Interests: Declarations. Ethics approval and consent to participate: The protocol of this study has been evaluated by the Ethical Committee of the MoH and given a positive vote on 9 August 2021. Written informed consent was obtained from parents or legal guardians of all children participating in the current study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: The 2009 H1N1 pandemic highlighted the need to routinely monitor severe influenza, which lead to the establishment of sentinel hospital-based surveillance of severe acute respiratory infections (SARI) in several countries in Europe. The objective of this study is to describe characteristics of SARI patients and to explore risk factors for a severe outcome in influenza-positive SARI patients., Methods: Data on hospitalised patients meeting a syndromic SARI case definition between 2009 and 2012 from nine countries in Eastern Europe (Albania, Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Romania, Russian Federation and Ukraine) were included in this study. An exploratory analysis was performed to assess the association between risk factors and a severe (ICU, fatal) outcome in influenza-positive SARI patients using a multivariate logistic regression analysis., Results: Nine countries reported a total of 13,275 SARI patients. The majority of SARI patients reported in these countries were young children. A total of 12,673 SARI cases (95%) were tested for influenza virus and 3377 (27%) were laboratory confirmed. The majority of tested SARI cases were from Georgia, the Russian Federation and Ukraine and the least were from Kyrgyzstan. The proportion positive varied by country, season and age group, with a tendency to a higher proportion positive in the 15+ yrs age group in six of the countries. ICU admission and fatal outcome were most often recorded for influenza-positive SARI cases aged > 15 yrs. An exploratory analysis using pooled data from influenza-positive SARI cases in three countries showed that age > 15 yrs, having lung, heart, kidney or liver disease, and being pregnant were independently associated with a fatal outcome., Conclusions: Countries in Eastern Europe have been able to collect data through routine monitoring of severe influenza and results on risk factors for a severe outcome in influenza-positive SARI cases have identified several risk groups. This is especially relevant in the light of an overall low vaccination uptake and antiviral use in Eastern Europe, since information on risk factors will help in targeting and prioritising vulnerable populations.