Seroepidemiology of Hepatitis A and Hepatitis E Infections in Ardabil, Northwest of Iran: A Cross-sectional Population Based Study

Background: Hepatitis A virus (HAV) and hepatitis E virus (HEV) are common viral infections worldwide, transmitted via the fecal-oral route. Unfortunately, there is no published data on the seroepidemiology of these two infections in the northwest of Iran. Objectives: This study aims to investigate the seroprevalence of HAV and HEV immunoglobulin G (IgG) antibodies in Ardabil, northwest of Iran. Methods: A cross-sectional study was conducted between 2018 and 2019 using 700 serum samples from family members of a population that was randomly selected. Blood samples were taken, and checklists were completed. The samples were tested using enzyme-linked immunosorbent assay (ELISA) for antibodies to HAV (anti-HAV) and anti-HEV IgG antibodies. The results of the study for both diseases were expressed using descriptive statistics, and the rate of positivity of samples in different age decades was compared analytically. Results: Our results showed that 135 (19.30%) and 401 (60.30%) out of 700 participants were seropositive for anti-HEV and anti-HAV IgG antibodies, respectively. The results indicate that there is a significant difference in the seroprevalence of hepatitis A and E. Hepatitis A has a significant upward trend starting from the beginning of the third decade, and by the end of the fourth decade, almost 100% of the tested individuals had a history of hepatitis A. On the other hand, hepatitis E shows a significant upward trend beginning in the early fifth decade, indicating that Ardabil experienced a hepatitis E outbreak 40 to 50 years before the study was conducted. Conclusions: The results demonstrate a significant difference in the seroprevalence of hepatitis A and E. These findings suggest that hepatitis A was endemic in Ardabil twenty years ago, but in the last twenty years, the circulation of the virus has decreased significantly. This finding also indicates that hepatitis E is not currently a common problem in the province, but due to the lack of herd immunity, there is a risk of outbreaks due to contamination of water or food sources.