Warning of hepatitis A outbreak among men who have sex with men in Europe

An outbreak of hepatitis A in Europe has affected 287 people in at least 13 countries, with large numbers of cases in the United Kingdom, Italy, Spain, Germany and the Netherlands. Public health authorities have identified three clusters of cases in which men who have sex with men (MSM) predominate. The European Centre for Disease Prevention and Control has called for vaccination campaigns to target MSM, and Public Health England is encouraging gay and bisexual men to seek vaccination.

Public health officials in New York and Hong Kong have also reported outbreaks among men who have sex with men since the beginning of 2017.

Hepatitis A causes an acute illness with fever, aches and pains, nausea, vomiting, jaundice and pale-coloured stools. The first symptoms may last for up to two weeks but jaundice (yellowing of the skin and eyes) and fatigue may persist for up to six months. 

The outbreak identified in the Netherlands, among men who had attended a sex-on-premises venue during the Europride festival in Amsterdam in August 2016, has been linked to cases in nine other countries, almost all in men. The outbreak identified in the United Kingdom is linked to cases in at least nine other countries. A third outbreak, first detected in Germany, has been linked to cases in six other countries, almost all in men. In each outbreak investigation the cases have been linked by genetic sequencing of the hepatitis A virus.

In the UK outbreak, men diagnosed with hepatitis A frequently reported travel to Spain, including Gran Canaria, or multiple sexual contacts, use of dating apps such as Grindr, use of sex-on-premises venues or co-infection with sexually transmitted infections. It is unclear whether travel to Spain resulted in exposure through sexual contact, or through contaminated food or water.

The German outbreak was first identified in Berlin in December 2016 among men who have sex with men. Approximately a third of the men diagnosed in Berlin reported the use of sex-on-premises venues. The Berlin investigation found that men were either unvaccinated or had only received one dose of vaccine. The German outbreak has not been linked to infections acquired in Spain.

Two hundred and eighty of the 287 confirmed cases have been diagnosed in men. Not all cases in men have been confirmed as men who have sex with men. Several cases of onward household transmission have also been identified in the United Kingdom and Germany.

The European Centre for Disease Prevention and Control emphasises the importance of hepatitis A vaccination for men who have sex with men living in areas of ongoing outbreaks or travelling to destinations where hepatitis A outbreaks have been reported among men who have sex with men.

A single hepatitis A vaccination protects against infection for 12 months. It normally takes around two weeks for immunity to develop after vaccination. A booster dose within 6-12 months should provide protection for around 20 years. In the United Kingdom, a combined vaccination against hepatitis A and hepatitis B is available to men who have sex with men through sexual health clinics.

Hepatitis A is shed in faeces and can be transmitted through food or drink contaminated with faeces. Hepatitis A can also be acquired through sexual contact, especially oral-anal sex (rimming). Fingers, hands or penises that come into contact with the anus and then the mouth could also provide a route of transmission. Public Health England has recommended that men wash their hands thoroughly after sex and change condoms between partners in order to reduce the risk of acquiring or passing on hepatitis A.