Introduction: In 2004 Denmark had an epidemic of hepatitis A among men who have sex with men (MSM). We estimate the size and the economic impact of the epidemic and discuss possibilities to prevent new epidemics.
Materials and methods: The size of the outbreak was estimated from notifications received by the Department of Epidemiology and the number of hepatitis A IgM positive specimens sent to the Department of Virology at Statens Serum Institut. The economical impact was estimated according to data on cost of illness from the National Board of Health and the results of the outbreak investigation.
Results: In 2004, 165 cases of hepatitis A in men > 17 years of age were reported compared with a yearly average of 25 cases in the previous 10 years. The size of the outbreak, adjusted for an estimated underreporting of 60% was 220 cases. The economical impact was EUR 650,000, or EUR 3,000 per case.
Conclusion: Outbreaks of hepatitis A among men who have sex with men are reported from major European cities almost on an annual basis. In the case of an outbreak, we suggest the response should include a targeted information campaign in the MSM media, hygiene control at gay saunas, sex clubs and darkrooms and a free vaccination offer to MSM with frequent partners at locations frequented by MSM. Before an outbreak we propose that vaccination against hepatitis A be recommended to MSM with frequent partners.