Hepatitis A in South Korea, 2026: 1,512 reported cases so far

1. The outbreak

1,512 cases of hepatitis A have been reported in South Korea in 2026, with counts running to 21 September 2026.

That is already more than the 1,132 reported in the whole of 2025 (1.3 times as many).

Case definition: reported cases. Figures are as reported by the originating public-health authorities and compiled by ENCLAI; they are not modelled estimates.

2. Modes of transmission and reservoirs

The hepatitis A virus is transmitted primarily by the faecal-oral route, which occurs when an uninfected person ingests food or water contaminated with the faeces of an infected person.¹ In households, transmission may occur through dirty hands when an infected person prepares food for family members.¹ Although infrequent, waterborne outbreaks typically stem from water that is inadequately treated or contaminated with sewage.¹ The virus can also be transmitted through close physical contact, such as oral-anal sex, with an infectious person, although casual contact does not spread the virus.¹

Hepatitis A is spread when someone ingests the virus, even in very small amounts, usually through person-to-person contact or by eating or drinking contaminated food or drink.² Since 2016, outbreaks in multiple states have been caused by person-to-person transmission, primarily among people who use drugs, people experiencing homelessness, and men who have sex with men.²

3. Epidemiology: risk groups, geography and seasonality

In low- and middle-income countries where sanitary conditions and hygienic practices are poor, 90% of children contract hepatitis A virus infection before age 10 years, typically without symptoms.¹ In high-income countries with good sanitary and hygienic conditions, infection rates are low, though disease may occur among adolescents and adults in high-risk groups such as persons who inject drugs, men who have sex with men, people travelling to areas of high endemicity, and isolated populations such as closed religious groups.¹ Large outbreaks have been documented in the United States of America among persons experiencing homelessness.¹

In low- and middle-income countries where sanitary conditions and hygienic practices are poor, 90% of children contract hepatitis A virus infection before age 10 years, typically without symptoms.¹ In high-income countries with good sanitary and hygienic conditions, infection rates are low, though disease may occur among adolescents and adults in high-risk groups such as persons who inject drugs, men who have sex with men, people travelling to areas of high endemicity, and isolated populations such as closed religious groups.¹ Large outbreaks have been reported in the United States of America among persons experiencing homelessness.¹

In low- and middle-income countries where sanitary conditions and hygienic practices are poor, 90% of children contract hepatitis A virus infection before age 10 years, typically without symptoms.¹ Infection rates remain low in high-income countries with good sanitary and hygienic conditions, although disease may affect adolescents and adults within high-risk groups, including persons who inject drugs (PWID), men who have sex with men (MSM), travelers to areas of high endemicity, and members of isolated populations like closed religious groups.¹ Large outbreaks have been documented in the United States of America among persons experiencing homelessness.¹

Since 2016, there have been outbreaks in multiple states caused by person-to-person transmission, primarily from person-to-person contact, especially among people who use drugs, people experiencing homelessness, and men who have sex with men.² In 2023, people aged 30–39 years had the highest rate of hepatitis A.² From 2022 to 2023, there was a 28% decrease in the number of newly reported HAV cases.² The number of hepatitis A cases in 2023 was 1.2 times as high as in 2015.² The rate of hepatitis A among Hispanic people was 2.0 times as high as the rate of hepatitis A among non-Hispanic White people.²

4. Significance as a public-health problem

A safe and effective vaccine is available to prevent hepatitis A.¹ Vaccination is the best way to prevent infection.² CDC recommends vaccination for all children ages 12–23 months, all children and adolescents between ages 2–18 years who have not been vaccinated, and all people, including pregnant women, with increased risk factors for hepatitis A.² In addition, it is important to practice good hand hygiene, including thoroughly washing hands after using the bathroom, changing diapers, and before preparing or eating food.² The WHO global surveillance system detects public health threats 24 hours a day, 365 days a year.¹ WHO receives regular notifications of HAV outbreaks and, when necessary, delivers a coordinated 3-level response to support its members states.¹ Since 2016, CDC has provided guidance and support to 37 states that have reported person-to-person outbreaks of hepatitis A.² To assist with outbreak investigations, CDC sent disease intervention specialists, epidemiologists, lab experts, and public health advisors to nine states.²

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Hepatitis A in South Korea: live counts and trend · Hepatitis A: all countries · Active outbreaks · How we verify