Viral hepatitis A in the Voronezh region: a controlled or «self-controlled» infection?

Abstract

Over the past decade, in most regions of Russia, including the Voronezh region, the epidemic process of viral hepatitis A (HAV) has been of low intensity. The aim of the study was to study the incidence of viral hepatitis A in the Voronezh region for the period 1993–2021, taking into account the results of laboratory studies conducted as part of epidemiological surveillance and preventive measures. The research materials were statistical forms approved by Rosstat, analytical reports of Rospotrebnadzor for the Voronezh region, departmental reports of regional medicaorganizations to the Regional Health Department. The data of examination for anti-HAV IgG of contact persons in the outbreaks were analyzed. The materials were processed using the methods of epidemiological analysis. A downward trend in the incidence of HAV with the properties of a «controlled» infection was established: the severity of seasonal rises, a shift in the proportion of cases to the adult population, school-age children. At the same time, coverage of HAV vaccination among the population of the region is low and cannot yet have a significant impact on reducing the incidence. Immunization is important in outbreaks to prevent group spread and during natural disasters. Against the background of improved provision of the population with quality water, the importance of water as a factor in the transmission of infection has decreased. During the study period, only one focus with a presumably waterway was noted. Complexes of preventive and anti-epidemic measures are being effectively implemented in the region. The selective vaccination used at this stage of the epidemic process is sufficient for the Voronezh region.