No 15 - 2011

Hepatitis B, HIV and syphilis screening of pregnant women 2010

The general screening of pregnant women for hepatitis B was introduced on 1 November 2005, EPI-NEWS 41/05 (pdf), while screening for HIV and syphilis were instituted as from 1 January 2010, EPI NEWS 27-33/10.

In 2010 a total of 67,831 blood type analyses were performed in pregnant women. Among these, 67,640 (99.7 %) were tested for hepatitis B (HBsAg), 64,282 (94.8 %) for HIV and 63,835 (94.1 %) for syphilis. The degree of completeness of the screening varied between blood banks, Table 1.

HBsAg-positive pregnant women

Of the 67,640 tests, a total of 198 were positives (0.3 %) which is at par with the level ob-served in previous years, Figure 1.

A total of 66 women, who were notified in the 2010 pregnancy screening, had tested HBsAG-positive in the general screening during previous pregnancies. Among these, 64 % were registered via the statutory notification system, while only 41 % of the women who tested HBsAg-positive for the first time in the general screening had been registered.
HBeAg was found in 31 of the 195 women (16 %) who were tested. The HBeAg occurrence was higher among women from South-East Asia, Table 2.

Sixteen of the women were adopted; 14 from Corea and two from India. Eight of these had been registered in the statutory notification system.

HIV-positive pregnant women

Among the 64,282 HIV tests, 45 (0.07%) were positive, ten in women with newly diagnosed HIV and 35 in women with known HIV. All 45 had been notified via the statutory notification system.

Furthermore, three pregnant women were notified with HIV via the national surveillance system without previously having been notified via the pregnancy screening initiative.

Two of these were newly diagnosed and one was known with HIV and had already commenced treatment. Among the newly diagnosed cases, two were Danes, one Asian and nine African. Among the ten immigrants with newly diagnosed HIV, three had immigrated within 1-3 years, six in 2010 and one had immigrated 12 years ago and had been infected in Denmark.

Among the women who were known with HIV, eight were Danes, three Asians and 25 Africans. One of these cases had been HIV positive since birth.

Pregnant women with syphilis

Among the 63,835 screening tests, a total of 155 were positives. Subsequently, 148 were re-tested, and hereof seven (0.01 %) came out positive in a full confirmatory test. The positives comprised two Danes, two Africans and one person of East European origin, and all were notified via the statutory notification system.

Commentary

The majority of the women who tested positive for hepatitis B, HIV or syphilis, belonged to risk groups previously covered by the selective screening.

However, a surprisingly high number of women were found who would not otherwise have been diagnosed even in an optimally performed selective screening. Particularly, it should be noted that seven unexpected laboratory confirmed cases of syphilis were detected.

This seems to indicate that syphilis is in the process of becoming reintroduced into the general public.

The objective of the screening is to avoid mother-to-child infection with the three conditions through vaccination of the neonate (hepatitis B) or treatment of the pregnant woman (HIV and syphilis).

Presently, in Denmark no children of HIV-positive mothers who were in treatment during pregnancy have been infected at birth. The fact that uninfected children are currently born by women who were themselves HIV-positive from birth demonstrates that HIV treatment has progressed considerably.

Notably, 30 % of the HIV-positive immigrant women diagnosed during the screening had resided in Denmark for several years. The National Board of Health (NBH) recommends testing of immigrants from countries with a high HIV occurrence as quickly as possible after their arrival to Denmark as HIV treatment is more effective when implemented early, and as treatment impedes further transmission, EPI NEWS 46/09 (pdf).

The finding of one of the three conditions should not lead to recommendation of a provoked abortion; rather such cases should be referred to a Department of Infectious Diseases. It is essential that the hepatitis B screening result be noted in the antenatal record so that the place of birth may institute timely vaccination of the neonate, EPI-NEWS 41/05 (pdf).

Furthermore, it is important that the record states that HIV and syphilis screenings have been performed and that the midwife offers to take a specimen, particularly in women of non-Danish origin and women who belong to a risk group. The NBH guideline states that the GP shall ensure that pregnant women who have screened positive for syphilis have a blood sample taken for full serological analysis, EPI NEWS 27-33/10. 

The general hepatitis B screening was not initially complete, EPI-NEWS 18/06 (pdf). Nor so was the general HIV and syphilis screening as not all blood banks have yet succeed in introducing well-functioning work procedures. However, at a national level, the overwhelming majority of pregnant women were screened in 2010.

All blood banks are expected to start using test kits with a superior specificity in 2011 to overcome the high share of false-positive results currently associated with syphilis screening tests.
(S. Cowan, A.H. Christiansen, B. Søborg, O. Wojcik, L. Roth, Dept. of Epidemiology, S. Hoffmann, DBMP) 

Individually notifiable diseases and selected laboratory diagnosed infections (pdf) 

13 April 2011