The Change in the Susceptible Populations with the Shift in Hepatitis A Epidemiology

Aim: The incidence of hepatitis A (HepA) has decreased due to vaccination and improved hygiene conditions. However, the age of onset of the disease has shifted from childhood to adulthood. Children with HepA are mildly symptomatic, whereas the course of the disease in adults may be severe. The aim of this study was to examine the change in HepA seroprevalence and identify the population susceptible to HepA.
Material and Methods: A total of 10132 patients who were tested anti-Hepatitis A virus immunoglobulin G (anti-HAV IgG) between 2016 and 2019 were reviewed retrospectively, and included in this study. The patients were divided into five groups according to their age, and seropositivity rates were compared between age groups. The relevant data of the healthcare professionals were also evaluated separately.
Results: The overall seropositivity rate was 60.1% (n=6088). The seropositivity rate was found 29.0% (n=944) in the 18 to 24 years range, 49.7% (n=837) in the 25 to 29 years range, 60.6% (n=689) in the 30 to 34 years range, 76.6% (n=784) in the 35 to 39 years range, and 93.3% (n=2834) in the ≥40 years groups. The seropositivity rate was found 36.1% (n=1781) and 82.9% (n=4307) in patients <30 and ≥30 years groups, respectively (p<0.001).
Conclusion: In recent decades, there has been a significant change in HepA seroprevalence. This change has resulted in the emergence of a young adult population susceptible to possible HepA outbreaks. Thus, seronegative young adults may be considered at risk for HepA and routine vaccination may be considered.