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Question: Geographical distribution of Hepatitis A

Answer: Geographical distribution areas can be characterized as having high, intermediate or low levels of hepatitis A virus infection. However, infection does not mean disease because children infected young do not experience any noticeable symptoms.

Areas with high levels of infection
In low- and middle-income countries with poor sanitary conditions and hygienic practices, infection is common and most children (90%) have been infected with the hepatitis A virus before the age of 10 years, most often without symptoms2. Epidemics are uncommon because older children and adults are generally immune. Symptomatic disease rates in these areas are low and outbreaks are rare.


Areas with low levels of infection
In high-income countries with good sanitary and hygienic conditions, infection rates are low. Disease may occur among adolescents and adults in high-risk groups, such as PWIDs, MSMs, people travelling to areas of high endemicity, and in isolated populations, such as closed religious groups.In the United States of America, large outbreaks have been reported among homeless persons.

Areas with intermediate levels of infection
In middle-income countries, and regions where sanitary conditions are variable, children often escape infection in early childhood and reach adulthood without immunity. Ironically, these improved economic and sanitary conditions may lead to accumulation of adults who have never been infected and who have no immunity. This higher susceptibility in older age groups may lead to higher disease rates and large outbreaks can occur in these communities.

(Source: World Health Organization (WHO), 20 Feb 2020)

Source Link: https://www.who.int/news-room/fact-sheets/detail/hepatitis-a