No 40 - 2011
Hepatitis A 2010
Hepatitis A 2010
2010 saw 47 notified cases of acute hepatitis A infection; 25 males and 22 females. The number of notified cases and incidence per 100,000 are presented in Table 1. The number of notified cases by origin and place of infection are shown in Table 2. Two Danes were reportedly infected in Turkey and one in each of the following countries: Austria, Egypt, Ethiopia and Venezuela.
Eight persons of foreign origin were infected in Afghanistan, four in Turkey, three in Pakistan, two in Egypt and one in each of the following countries: Algeria, Lebanon, Syria, Iraq, India and Burkina Faso. Among the notified cases, the vaccination status was stated for 17 (36%) none of whom were vaccinated. Among 12 (67%) of the 18 cases infected in Denmark, the source of infection was stated as unknown; furthermore, two were infected via family members, two via children in day-care institutions and two via hetero-sexual contact.Among the 29 cases infected abroad, the source of infection was unknown in 21 (72%), the remaining cases were recorded as food-related infection in connection with vacations and stays abroad.
Virus typingSince 2006, hepatitis A virus typing (HAV) has been performed routinely, as positive HAV IgM serum specimens are submitted to the SSI Virology Department where PCR-positive specimens are sequenced. In 2010 specimens were received from 28 (60%) of the notified cases, including 24 (86%) PCR-positives. Furthermore, samples were received from eight unnotified cases, all PCR-positives. The detected virus types - 1A, 1B and 3A were in accordance with epidemiological information provided on countries of infection.
OutbreaksIn 2010 a total of three outbreaks were detected. One outbreak comprised two siblings aged 12 and 15 years who were infected during a family visit to Afghanistan. Another outbreak comprised three siblings aged 4, 8 and 12 years, who were also infected during a family visit to Afghanistan. None of the five children had received hepatitis A vaccination prior to their journey. The third outbreak comprised nine persons, including eight who were reported to the Department of Epidemiology. The index case was a child infected after a family visit to Turkey. The child was the only person in the family who had not received hepatitis A vaccination. The nine cases comprised four pre-school children, two school children and three adults, EPI-NEWS 5/11. HAV genotyping was in accordance with the epidemiological information as identical HAV was found in the patients of each outbreak.
Development 2000-2010The overall number of notified acute hepatitis A infections and incidence for the 2000-2010 period are presented in Table 3. The highest incidences were found among persons < 20 years of foreign origin. The incidence in this group decreased during the period, but remains markedly higher than that of persons of Danish origin, Figure 1.
CommentaryThe number of notified acute hepatitis A cases remained nearly unchanged with respect to 2009, EPI-NEWS 40/10. Among the notified cases children of foreign origin comprised the larger share. A considerable share of the cases infected abroad was children infected in connection with prolonged family visits. None of the notified cases had received hepatitis A vaccination prior to their travels.
Children of immigrants who have been raised in Denmark will frequently not have been exposed to HAV infection and are therefore susceptible to infection. HAV has been receding in Denmark for the past seven years and there is a trend towards cases being limited to children of immigrants who visit their families in their countries of origin and to Danish travellers. These may then subsequently spread the disease in Denmark. It is essential that the vaccinating physicians remain attentive to hepatitis A vaccination in this group. To counter the problem, some European countries (e.g. England) have introduced free vaccination of immigrant children before family visits to highly endemic areas.
(B. Søborg, S. Cowan, Department of Epidemiology, B. Böttiger, Department of Virology)
5 October 2011