Epidemiology

Hepatitis A virus (HAV) infection is endemic in resource-limited countries.[1] In developed countries, outbreaks are associated with contaminated food or water. Men who have sex with men, people who use illegal drugs, people who experience homelessness, and people who travel to endemic areas are at higher risk of infection.[1][5] There are an estimated 1.4 million cases per year globally.[5]

High-prevalence areas include Africa and parts of Asia and Latin America.[6][7][8][9] The majority of infections in these areas occur in early childhood; infections are often asymptomatic in children and reported incidence rates are low. In high-prevalence areas, adults are generally immune.

Regions of Southern and Eastern Europe and parts of the Middle East have intermediate prevalence.[10] Areas of low prevalence and very low prevalence include North America and Western Europe, where few people are infected in childhood and the majority of the population remains susceptible throughout adulthood.[10][11][12][Figure caption and citation for the preceding image starts]: Geographic distribution of the prevalence of hepatitis A (based on summary of available data)CDC website; used with permission [Citation ends].com.bmj.content.model.Caption@3780e46e

In the US, HAV infection continues to be one of the most frequently reported vaccine-preventable conditions.

An outbreak of HAV infection was seen in the US from 2015 to 2020. The cases started decreasing from 2020, and eight states declared the end of the outbreak in 2021. In 2021, the Centers for Disease Control and Prevention received 11,500 reports of HAV infection from US states and territories, which is 4% higher than that in 2015 but 43% lower than that in 2020.[13]

There have been an estimated 44,910 cases, 27,441 hospitalizations, and 423 deaths following HAV infection since the hepatitis A outbreaks were first identified in 2016.[14] In 2021, 3864 cases of hepatitis A were reported by 30 European Economic Area countries.[15]

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