Evolution of hepatitis A virus seroprevalence among HIV-positive adults in Taiwan.

Objectives: The study aimed to describe the seroprevalence of hepatitis A virus (HAV) in HIV-positive adult patients in Taiwan between 2012 and 2016 and to examine the evolution of HAV seroprevalence between 2004-2007 and 2012-2016.
Methods: Clinical information and data of anti-HAV antibody results were collected from 2,860 antiretroviral-naïve HIV-positive Taiwanese aged 18 years or older who initiated combination antiretroviral therapy at 11 hospitals around Taiwan between 2012 and 2016 (2012-2016 cohort). A multivariate logistic regression model was applied to identify independent variables associated with HAV seropositivity. Comparisons of HAV seroprevalences and associated clinical characteristics were made between this 2012-2016 cohort and a previous cohort of 1580 HIV-positive patients in 2004-2007 (2004-2007 cohort).
Results: Of the 2,860 HIV-positive patients between 2012 and 2016, the overall HAV seropositivity rate was 21.2% (605/2860), which was independently associated with an older age (adjusted odds ratio [AOR], per 1-year increase, 1.13; 95% confidence interval [95% CI], 1.11-1.15) and co-infection with hepatitis B virus (AOR 1.44; 95% CI, 1.08-1.93). Residence in southern Taiwan (AOR 0.49; 95% CI, 0.34-0.72) was inversely associated with HAV seropositivity. The overall HAV seroprevalence in the 2012-2016 cohort was significantly lower than that in the 2004-2007 cohort (21.2% vs 60.9%, p<0.01). The decreases of HAV seropositivity rate were observed in nearly every age-matched group, which suggested the cohort effect on HAV seroepidemiology. However, among individuals aged 25 years or younger, the HAV seropositivity rate increased from 3.8% (2/52) in the 2004-2007 cohort to 8.5% (50/587) in the 2012-2016 cohort, with 95.4% (560/587) being MSM in this age group of the latter cohort.
Conclusions: HAV seroprevalence has decreased with time among HIV-positive adults in Taiwan. The cohort effect has increased the number of young HIV-positive patients that are susceptible to HAV infection in a country without nationwide childhood vaccination program against HAV.