Patrick J. E. Bindels

Trends in mortality among AIDS patients in Amsterdam, 1982-1988.

In this study we evaluated the survival of 515 AIDS patients diagnosed in Amsterdam between 1982 and 1988 and followed-up until April 1990. Non-resident patients survived for a shorter period than resident patients (median survival time 10 versus 16 months). Residents had a 1-, 2- and 3-year survival of 56.1, 33.0 and 17.2%, respectively. Heterosexual intravenous drug users tended to have a better survival than homosexual men, although this was not significant. The survival time was longer for AIDS patients less than 30 years of age at diagnosis and varied for the different clinical manifestations leading to AIDS diagnosis. We calculated the 1- and 2-year survival probability by year of diagnosis for patients initially presenting with a Pneumocystis carinii pneumonia (PCP). The 1-year survival improved greatly in 1986 and continued to rise in the following years. The 2-year survival was similar in 1986 and 1987 (26.8 versus 28.2%) but increased in 1988 (38.9%). We conclude that besides better clinical experience and diagnostic methods, this improvement in prognosis could be explained by the start of secondary prophylaxis for PCP in 1985 and the introduction of zidovudine therapy in 1987.

The HIV prevalence among pregnant women in the Amsterdam region (1988–1991)

The objective of the study was to monitor the HIV prevalence in the years 1988–1991 among pregnant women in the Amsterdam region, visitors to an abortion clinic and 3 outpatient infertility clinics. All women attending these clinics were asked to participate in the study on a voluntary basis and were tested with informed consent. The women were questioned about risk-bearing behaviour of themselves and their sexual partner(s). In the period 1988–1991, of the 23,827 eligible pregnant women, 22,165 women participated (93.0%). Twenty-seven women were found to be positive for HIV antibodies (0.12%, 95% CI: 0.08%–0.17%), of whom twenty belonged to a known HIV risk group or had a partner who belonged to one of these groups and 7 women had no known HIV risk. Seventeen of the 27 women had a foreign nationality. The annual HIV prevalence among pregnant women was: 1988: 0.28%; 1989: 0.10%; 1990: 0.10%; 1991: 0.11%. In the years 1990 and 1991, of the 1,128 eligible women visiting the abortion clinic 953 (84.5%) were tested. Eleven women were HIV-seropositive (1.15%, 95% CI: 0.6%–2.0%), of whom 9 were from an AIDS endemic region, 1 woman had a partner from this region and 1 woman had no known HIV risk. Four African women had HIV-2 antibodies. At the 3 outpatient infertility clinics 1 woman was found to be HIV-positive (0.13%; 95% CI: 0.02–0.9). She had no other risk than a partner from an AIDS endemic area. In the Amsterdam region there was a steady and low HIV prevalence (0.1%) among pregnant women through the years 1988–1991. The prevalence in the abortion clinic was ten times higher. The program was able to detect possible high risk groups within the population. Migration and travelling can play an important role in the spread of HIV in the general heterosexual population.

Determinants of penicillinase producing Neisseria gonorrhoeae infections in heterosexuals in Amsterdam.

BACKGROUND AND OBJECTIVES--At the STD clinic of the Municipal Health Service in Amsterdam, the annual number of infections with penicillinase-producing Neisseria gonorrhoeae (PPNG) strains remained relatively stable from 1983 until 1990, while the number of non-PPNG infections declined dramatically. To investigate the PPNG and non-PPNG epidemic, a cross sectional study was conducted in 1989 and 1990. The purpose of this study was to assess determinants of PPNG infections among heterosexuals diagnosed with gonorrhoeae. METHODS--In addition to routinely collected data in new consultations for STDs, information on alcohol use, drug use and sexual behaviour was obtained from patients diagnosed with gonorrhoea. The diagnosis of gonorrhoea was based on a positive culture and isolates were screened for PPNG. Logistic regression analysis was used to assess independent predictors of PPNG infection. RESULTS--Additional information was available of 328 women and 995 heterosexual men diagnosed with gonorrhoea. PPNG was diagnosed in 86/328 (26%) women and in 329/995 (33%) men. Logistic regression analysis identified a Central/South American nationality (odds ratio(OR) = 2.46) and older age (OR = 1.04 per year) as positively associated with PPNG infection in female patients. An inverse relation was found with use of hard drugs (OR = 0.29). Among men diagnosed with gonorrhoea, sexual contacts with window prostitutes (mainly women from Central/South America) (OR = 1.98) and a foreign nationality (OR = 1.78) were positively associated with PPNG infection, and sexual contact with drug using prostitutes (OR = 0.47) inversely. CONCLUSIONS--PPNG infections were especially common among Central and South American window prostitutes and their clients, but not among hard-drug addicted prostitutes and their clients. Since window prostitutes originating from Central and South American countries are transient in Amsterdam, prevention activities targeted at these prostitutes and their clients should be continued to limit the spread of PPNG and other STDs within these groups.

Evaluation of an expanded two-ELISA approach for confirmation of reactive serum samples in an HIV-screening programme for pregnant women

Serum specimens were collected from 31,232 pregnant women in Amsterdam between 1988 and 1995 in a screening programme for human deficiency virus (HIV) infection. The sera of 56 (0.179%) women tested were confirmed as positive for HIV. A total of 67 sera reacted positive or borderline by the screening enzyme‐linked immunosorbent assay (ELISA) and indeterminate or negative by HIV‐1 Western blot; 42 of these specimens were available for evaluation of the strategy for diagnosis of HIV infection. A two‐ELISA approach with the second ELISA based on a principle different from that of the screening ELISA, expanded with the use of a membrane immunoassay based on two synthetic peptides specific for HIV‐1 gp41 and HIV‐2 gp36 envelope proteins, was compared with the Western blot analysis. Indeterminate results were resolved with a nucleic acid sequence‐based amplification assay (NASBA) for HIV‐1 RNA and a strip immunoassay (SIA) for the simultaneous detection of antibodies to HIV‐1 or HIV‐2 and HIV‐1 p24 antigen. Eleven samples were weakly or borderline positive by the screening test and gave indeterminate results by Western blot. The expanded two‐ELISA approach designated these sera as HIV‐negative, and confirmed negative by NASBA and the SIA. Twenty‐one samples showed borderline or positive results on the screening test and negative results by Western blot. Again, these sera were characterised as HIV‐negative by the expanded two‐ELISA procedure, and this characterisation was confirmed by both NASBA and the SIA. Five HIV‐2‐positive serum samples were recognised by the expanded two‐ELISA approach and the SIA; these sera were negative by NASBA. Finally, another five serum samples were weakly or borderline positive by both ELISAs and positive by the membrane immunoassay; of these five, two sera generated positive patterns and the other three indeterminate patterns on Western blots, and four were positive by the NASBA assay. Follow‐up serum specimens from these five women were negative and the reactivity of the initial specimens was thus likely to have been the result of cross‐contamination. Our results demonstrate the effectiveness of a simple confirmation approach of two HIV ELISAs expanded with a membrane spot assay to discriminate between infection with HIV‐1 or HIV‐2. The data also indicate the importance of retesting individuals with indeterminate or positive confirmational results to exclude the possibility of contamination as the cause of reactivity of the original specimen. J. Med. Virol. 54:285–290, 1998.