The formation of morbidity and the risk of developing hepatitis A in the population of the Russian Federation

Introduction. Outbreaks of viral hepatitis A (HAV) remain of socio-economic importance, but the role of the water factor has not been sufficiently studied, which reduces the effectiveness of prevention. The epidemic HAV potential determines the relevance of analyzing risk factors and predicting morbidity.Purpose to study risk factors and predict the incidence of hepatitis A based on water contamination and vaccination rates in the Russian Federation.Materials and methods. In 2014–2023, water samples (n = 170,372) were taken from sources of centralized and non-centralized water supply, surface and wastewater in 89 regions of the Russian Federation. The studies were carried out by the serological method, statistical processing was carried out using the R software.Results. During the studied period, the average HAV contamination was: in centralized water supply — 0.09% (95% CI 0.07–0.11), non—centralized — 0.31% (95% CI 0.17–0.53), surface reservoirs — 0.14% (95% CI 0.11–0.19), wastewater — 0.41% (95% CI 0.35–0.48). There was a tendency to decrease the proportion of positive samples in non-centralized water supply (r = –0.78; p = 0.01) and wastewater (r = –0.87; p = 0.001). The incidence of HAV has a strong direct correlation with contamination of non-centralized water supply (r = 0.75; p = 0.01) and wastewater (r = 0.70; p = 0.03), as well as a moderate correlation with the vaccination rate (r = –0.69; p = 0.047). Linear regression equations reflecting the effect of morbidity on wastewater contamination and the effect of vaccination on morbidity are obtained.Research limitations. The official data on the HAV incidence in the Russian Federation for 2014–2023 were used, which ensures a representative sample.Conclusion. The data obtained can be used to predict the incidence of HCV, assess the associated economic damage, as well as to calculate the level of wastewater contamination for planning preventive measures.Compliance with ethical standards. This study did not require the conclusion of the biomedical ethics committee (the study was based on publicly available official statistics).Contribution of the authors: Badamshina G.G. — collecting material, conducting research, analyzing literature, statistical processing, analyzing data obtained and editing; Gafarova L.F. — conducting research, analyzing literature, statistical processing, analyzing data obtained and editing; Poptsova E.A. — conducting research, analyzing data obtained and editing; Trukhina G.M. — collecting material, literature analysis, data analysis and editing; Samotoina A.A. — collecting material, conducting research and editing; Yuzlibaeva L.R. — literature analysis, analysis of obtained data; Malinnikova E.Yu. — article editing; Fatkhutdinova L.M. — idea and development of the concept of the article, literature analysis, analysis of the data obtained and scientific editing of the article; Ilyinskaya O.N. — scientific and final editing of the article. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Funding. The study had no sponsorship.Conflict of interest. The authors declare no conflict of interest.Received: July 28, 2025 / Accepted: February 19, 2026 / Published: April 30, 2026