F. Cazein, F. Hamers, J. Alix, J-B. Brunet
European Centre for the Epidemiological Monitoring of AIDS, Saint-Maurice, France
With thanks to national coordinators from countries of the WHO European Region. This activity is funded by the Commission of the European Communities (DGV).
The HIV/AIDS pandemic is primarily caused by HIV-1. Another type of virus, HIV-2, is found mainly in certain West African countries (1-5). In Europe, most of the cases of HIV-2 infection described have been in people from Africa (6). The objective of this study was to examine the prevalence of HIV-2 infection in European countries, and to compare it with the seroprevalence of HIV-1 infection in the populations tested.
Seroprevalence studies that provide data on HIV-2 were selected from the European HIV prevalence database. This database, managed by the European Centre for the Epidemiological Monitoring of AIDS, includes aggregated data on published and unpublished seroprevalence studies provided by HIV/AIDS surveillance coordinators from participating countries. The data on HIV-2 have been checked and completed as necessary by the national coordinators.
Results [Table 1]
Forty-five of the 186 seroprevalence studies included in the European HIV prevalence database, provided separate data for HIV-1 and HIV-2. The studies were carried out between 1989 and 1995 in 22 countries. They include national results from screening blood donations (17 countries) and seroprevalence surveys of pregnant women (five countries), people attending sexually transmitted diseases (STD) clinics (six countries), and other selected populations such as injecting drug users (IDU).
Of the 35 156 852 blood donations tested in 17 countries, 855 were positive for HIV-1 and only 6 for HIV-2. Cases of HIV-2 infection were found in France (3), Estonia (1), Greece (1), and the United Kingdom (1). In these four countries, the prevalence of HIV-2 in blood donations was less than 0.3 per 100 000.
Among 617 463 pregnant women tested during antenatal care or at delivery in France, the Slovak Republic, Slovenia, and the United Kingdom, 738 were positive for HIV-1 and seven (one in Paris and six in London) for HIV-2.
Among 32 584 women who had terminations of pregnancy and were tested in France, the Netherlands, and the United Kingdom, 212 were HIV-1 positive and seven (two in Paris, two in London and three in Amsterdam) were HIV-2 positive.
Sexually transmitted diseases clinic attenders
Among 275 340 patients tested in STD clinics in the Czech Republic, France, Portugal, the Slovak Republic, Slovenia, and the United Kingdom, 3885 were positive for HIV-1 and 11 for HIV-2. Although HIV-1 positive subjects were found in each of these studies, HIV-2 positive subjects were found only in the United Kingdom (5, equivalent to 0.1% of all HIV positive STD patients) and Portugal (6, equivalent to 13% of all HIV positive patients attending STD clinics).
One HIV-2 positive case was also found in Portugal among 2342 IDU tested (0.5% of all HIV positive IDU) and four among 767 patients with tuberculosis tested (29% of all HIV positive patients with tuberculosis). Forty-one cases of HIV-2 infection were found among 2799 people with haemophilia in Spain (3.5% of all HIV positive people).
The estimation of HIV-2 prevalence is not usually the main objective of seroprevalence studies, and there are fewer data on HIV-2 than on HIV-1. Moreover, these data are heterogeneous in terms of study populations which makes comparisons between countries difficult. The most comparable data are those obtained from screening blood donations and testing pregnant women.
Blood donors are a population at low risk for HIV infection. Among the 17 countries examined and for the periods considered, the two countries with the highest proportion of HIV-1 positive donations – France and Greece – were among the four where at least one HIV-2 positive donation was detected.
The prevalence of HIV infection in pregnant women is considerably higher than among blood donors. As with HIV-1, HIV-2 infection is commoner among women who have terminations of pregnancy than among those who seek antenatal care or deliver.
Although these data are sparse, they confirm that HIV-2 is relatively rare in Europe. HIV-2 accounts for less than 1% of all HIV infections in most studies examined. This review and other studies (7-10) indicate however, that compared with other countries examined, the prevalence of HIV-2 infection is considerably higher in Portugal where HIV-2 infection accounts for 13% of all HIV positive STD patients and 29% of all HIV positive TB patients.
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7. Benito-Garcia A, Goncalves H, Pista A, et al. HIV-2 in Portugal: situation in l990. San Francisco:VIth international conference on AIDS; 1990 (abstract FC 662).
8. Botas J, Tavares L, Carvalho C, et al. HIV2 infection: some clinical and epidemiological aspects in Portugal. Montreal: Vth international conference on AIDS; 1989 (abstract MAP 77).
9. Victorino R, Teles LC, Ferreira MO, et al. Analysis of a screening program for HIV1 and HIV2 infection in women of reproductive age. Florence: VIIth international conference on AIDS; 1989 (abstract A 512).
10. Benito-Garcia A, Faria A, Ayres L et al. HIV-2 seroprevalence among the population attending the AIDS reference laboratory in Portugal. Florence: Vth international Conference on AIDS; 1991 (abstract MC 3019).