Immunity to Hepatitis-A virus: A nationwide population-based seroprevalence study from Iran

The mortality rate of acute Hepatitis A increases from 0.1% in the children to 1.2%, in the adults. Hepatitis A is efficiently prevented by HAV-vaccine, but the strategy for distributing this vaccine among countries is dependent on their level of immunity to HAV. This study aimed to detect the level of immunity to HAV in Iran.

In this population-based seroprevalence study, 5419 participants from 12 of provinces of Iran, including 57 urban and 120 rural areas were chosen through a multi-stage cluster random sampling. Participants were interviewed by filling checklists and 3 cc of blood sample was obtained from each of them. IBM SPSS statistics V.21 software was used for univariable and multivariable analysis of data.

Mean of age of Interviewees was 26.4 ± 16 years, ranging from 1 to 94 years with a male to female ratio 1.02. Overall, 3603 (66.5%) of subjects were seropositive for HAV-IgG. Among the age groups, 41.1% of children by the age 15 years and 82.6% of adults around 30 years old were immune to HAV. The Mid-point age of population immunity was 21 years. Residents of the borders of the country, people who had less access to the safe water or sanitary toilet, individuals with low socioeconomic status and persons who were a member of dense families had the most probability of seropositivity.

This study showed that Iran is among HAV low endemic countries and vaccination against HAV is recommended only in the high-risk population, including patients with chronic liver diseases, patients with coagulopathy, travelers to the high endemic areas, and homosexuals. Establishment of national HAV surveillance system, concerning of health system about the occurrence of the HAV outbreaks, implementation of harm reduction strategies, improving economic indices and sanitation and access to the safe water in the deprived regions is recommended.