Hepatitis A, outbreaks in 6 EU countries and in the UK: also sexually transmitted

Ecdc: “Data suggests that there has been human-to-human transmission and perhaps also through contaminated food”

Outbreaks of hepatitis A have been reported in 6 countries of the European Union and the United Kingdom. As of 29 September, the European Center for Disease Prevention and Control informs, 303 cases have been identified, caused by identical or closely related viral strains. The highest numbers – 161 cases, of which 139 are men and 22 women – were recorded in Hungary which is also the first country to report an outbreak. The other reported infections are distributed in Austria (7), Germany (8), the Netherlands (8), Slovenia (35), Sweden (8), and the UK (76). As for the dynamics of the contagion, the ECDC points out that “the epidemiological and microbiological data currently available suggest that human-to-human transmission has occurred, and perhaps also transmission through contaminated food”.

It was February 15, 2022 when Hungary reported an outbreak of genotype Ib Hav virus hepatitis. The onset of the disease of the first case dates back to the beginning of December 2021. The presence of this strain is confirmed in the 161 cases analyzed in the National Hepatitis Reference Laboratory in Hungary. The weekly number has been decreasing since June 2022. “Several infected people have identified themselves as men having sex with men (MSM), suggesting a possible transmission between sexual contacts”, highlights the ECDC in a note in which it takes stock . Among the patients there were several who were hospitalized.

Among the various hypotheses put forward, a food-borne outbreak was suspected in July 2022 with a link to a Hungarian restaurant where 16 people fell ill with Hav Ib infection. Some patients have reported eating a frozen berry dish. In the UK, no clear source of infection has been identified, but epidemiological investigations so far indicate possible food-borne infections in addition to person-to-person transmission. Germany, the Netherlands and Sweden reported a total of 9 cases infected with strains corresponding to the sequences of the British strain. Investigations into these cases have found no clear risk factors for infection such as a travel history or berry consumption. Further investigations are underway, explains the ECDC.

Hepatitis A is highly transmissible through contaminated water, food and fecal-oral route between close contacts (i.e. family contacts, sexual contacts and contacts in kindergartens or schools). The average incubation period is 4 weeks, for a range of 2 to 6 weeks. The virus is highly resistant to environmental conditions and also to different storage methods such as acidification or freezing. “Therefore, possible foodborne transmission should be investigated when multiple infections are reported in a short period”, highlights the ECDC, which suggests practicing good hand hygiene, including washing them thoroughly with soap after using the toilet, changing hands. diapers and before preparing or eating food.

“Increasing surveillance to detect and investigate sporadic cases and case groups potentially associated with foodborne transmission in collaboration with food safety authorities is essential,” adds the EU body.

Vaccination against hepatitis A, ECDC continues, “is safe and highly effective”. The World Health Organization and most EU / European Economic Area countries recommend MSM for men. And among the other weapons of prevention, the use of condoms and good personal hygiene are indicated. “For primary prevention advice, authorities should consider engaging with civil society, social media, media outlets and dating apps to raise awareness among MSM about the risk of HAV and the importance of vaccination “, concludes the center.