Modern Features of Hepatitis a Epidemic Process in Large City of European Russia

Abstract

Purpose of the study was to characterize modern features of hepatitis A epidemic process in large city of European Russia and optimization of epidemic surveillance of the infection.Materials and methods. Hepatitis A incidence data were analyzed in long-term period 1968–2017. Etiologic structure of acute viral hepatitis was identified by both incidence data and extended set of viral hepatitis markers in patients with jaundice (n = 144). Anti-HAV prevalence rate was studied in population of N. Novgorod by immuno-enzyme method in 2014 and 2017 (n = 1728, age: 1–60 years old).Results and discussion. Share of hepatitis A in etiology of acute viral hepatitis did not significantly change in 2007–2017, if compared to 1994–2006 (50,8 ± 9,2% and 56,1 ± 13,3% respectively, р > 0,05), but it varies greatly depending on the phase of epidemic process of the infection. Modern period is characterized by 9 times reduction of the incidence rate and extension of epidemic cycle up to 10 years. Age structure of morbidity in modern conditions is defined by age groups of children 3–14 years old. Seasonal variability of the incidence rate was reduced in non-epidemic phase of epidemic process and in age group of adults. Anti-HAV antibodies were detected in 30,9 ± 1,9% of the city population in 2014, and this rate was even lower in 2017 (24,8 ± 1,6%). This data indicates that non-epidemic phase seroprevalence in modern conditions has decreased when compared to former period (from 51,5 ± 1,9% in 1998, p < 0,001). These changes primarily affect group of adults 30–59 years old.Conclusion. Presented characteristics of hepatitis A epidemic process play crucial role in the risk assessment of hepatitis A in modern period and must be implemented as first step in optimization of epidemic surveillance of hepatitis A.