WHO Position Paper Hepatitis A vaccines

Data on the endemicity of hepatitis A virus (HAV) infection in Africa and the Middle East are scant, but most of Africa appears to remain a high endemicity region, with the exception of subpopulations in some areas, e.g. White people in South Africa. Saudi Arabia is a model for the Middle East, and is a country in which shifting HAV epidemiology has been documented in recent years, concurrent with the social and economic development that has occurred over the last two decades. Earlier studies generally showed very high prevalence rates, with most people becoming infected in early childhood. Between 1989 and 1995, however, there was a significant fall in the seroprevalence of antibodies to HAV in children up to 12 years old throughout the country except in one region bordering the Yemen. The highest seroprevalence is found in children from rural backgrounds, while the seroprevalences in Bedouin and urban children are similar. Seroprevalence is related to socioeconomic status, being highest in the lowest groups. Similar findings have been reported from other countries in the Middle East. The existence of pockets of high endemicity for HAV infection with surrounding areas shifting towards intermediate endemicity may lead to outbreaks, and widespread vaccination should be considered.