DH successfully interrupts hepatitis A transmission chain among specific group by providing free hepatitis A vaccination to men who have sex with men
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During the six-month period from September 2025 to February 2026, Hong Kong recorded 24 cases of hepatitis A infection whose viruses were found to be genetically identical, involving 22 males and two females. Over 60 per cent of the male patients identified themselves as MSM. To control the transmission chain, the CHP has been providing two doses of hepatitis A vaccine free of charge to MSM since March 12, aiming to protect public health. As of July 31, more than 280 MSM had been vaccinated.
The number of hepatitis A cases among MSM has dropped significantly due to the CHP's multipronged measures, including enhanced public education and the provision of free vaccines to a specific group.
The CHP recorded five and two cases of hepatitis A infection in June and July respectively, representing a sharp decline from 15 cases recorded in January and a return to baseline levels. The CHP's epidemiological investigation showed that the patients in the past two months range in age from 21 to 83. Three of them identified themselves as MSM. Genetic analysis by the CHP revealed that no case recorded after June harboured the virus genetically identical to the aforementioned cluster of infections involving MSM. The CHP will continue to closely monitor the situation and take appropriate follow-up actions.
Hepatitis A virus is primarily transmitted through the ingestion of contaminated food or water, or contaminated hands before eating. The virus can also be transmitted through high-risk sexual contact. The incubation period of hepatitis A is usually 14 to 28 days, though it can last up to 50 days. Due to the long incubation period, symptoms such as fever, malaise, abdominal discomfort, loss of appetite, nausea, diarrhoea and jaundice may not appear until one to two months after infection.
Scientific literature indicates that, apart from foodborne transmission, hepatitis A outbreaks have occurred among MSM populations in many regions worldwide in the past. Due to the long incubation period, outbreaks transmitted through person-to-person contact tend to persist longer. Between 2015 and 2017, Hong Kong also experienced hepatitis A transmission chains involving MSM, which were successfully interrupted by vaccinating the affected at-risk groups. According to the Scientific Committee on Vaccine Preventable Diseases under the CHP, individuals in high-risk groups (including MSM) should consult their doctors about receiving hepatitis A vaccination to protect their personal health.
For more information on hepatitis A, please visit the CHP's website.
Ends/Wednesday, August 12, 2026
Issued at HKT 11:06
Issued at HKT 11:06
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