No 4 - 2010

2008 saw 26 notifications of acute hepatitis B virus (HBV) infection; 20 male and six female cases, Table 1. The median age was 34 years (range 16-68 years). A total of 17 (65%) were Danish by birth, and 10 (35%) were immigrants. The incidence was 0.5 per 100,000. Fourteen patients (54%) were infected in Denmark; of these, 11 were Danish-born and three immigrants. Six were infected by heterosexual contact and five by Intravenous Drug Use (IDU). One case was infected by close social contact. In the remaining two cases, the mode of infection was unknown. A total of 12 (46%) cases were infected abroad, six were Danish-born and six immigrants. Seven were infected by heterosexual contact, two by close social contact, and in three cases the mode of infection was unknown.

Chronic Hepetitis B 2008

In 2008, a total of 153 cases of chronic HBV infection were notified, Table 2. A total of 80 (52%) were males and 73 (48%) females, Table 3. The median age was 37 years for males (range 6-73 years) and 32 years for females (range 1-60 years). Among the 153 cases, 19 (12%) were of Danish origin and 134 (88%) of foreign origin. The group counted a total of 42 nationalities, including 58 (43%) from Asia, 25 (19%) from Africa, 21 (16%) from Turkey, 17 (13%) from Europe, 11 (8%) from MENA countries (the Middle East and North Africa), one from Greenland and one from the Caribbean. Mode of infection by origin is shown in Table 4. Both cases of nosocomial infection were infected at hospitals abroad. Perinatal infection was the notified mode of infection for four adult Danish-born females. Four children to mothers of foreign origin were infected at birth in Denmark prior to the introduction of general HBV screening of pregnant women in 2005, EPI-NEWS 41/05.

During the two-year period when the Department of Epidemiology monitored the screening of pregnant women using, among others, notifiability reminders for physicians, the number of 20-39-year-old women notified with chronic HBV infection increased. Since monitoring efforts ended, at year's end 2007, the number of notifications in the mentioned age-group has dropped to the level observed before monitoring was initiated, Figure 1. However, data from laboratories show that the number of pregnant women who are diagnosed with chronic HBV infection via general screening of pregnant women has remained stable, Figure 2.

Commentary

The number of notified cases of acute HBV infection has decreased steadily over the latest 25 years, EPI-NEWS 4/05, and the risk of HBV infection in DK remains very low. The highest occurrence of chronic HBV infection in Denmark is observed among immigrants from non-western countries. The introduction of general HBV screening of child-baring women with subsequent vaccination of neonates to carrier mothers marks an effort against mother-to-child infection which is the more frequently occurring type of infection in this group and the mode of infection which most frequently lead to chronic HBV infection. Even though the number of notifications among 20-39-year-olds has returned to the level observed before the introduction of general screening, the number of HBV diagnosed cases among child-bearing women remains unchanged. This seems to indicate that the general screening is still effective. Screening of child-bearing women has shown that there are a number of undiagnosed, asymptomatic HBV carriers among young immigrant women. Physicians are encouraged to screen these women's families to facilitate prophylactic measures as well as treatment. Furthermore, we take this opportunity to stress that HBV is notifiable.

(M. Malling, S. Cowan, Department of Epidemiology)

Individually notifiable diseases and selected laboratory diagnosed infections  

27 January 2010