J. A. R. Van Den Hoek

A longitudinal study on the incidence and transmission patterns of HIV, HBV and HCV infection among drug users in Amsterdam

In the present study data on the incidence of HBV and HCV were used to indicate the prevalence of and trends in risk behavior, assuming that drug users (DUs) who become infected with HBV or HCV are also at risk for infection with HIV. In addition, we determined to that extent the transmission patterns of HIV, HBV and HCV differed. DUs were selected from a cohort study in Amsterdam, had at least one follow-up visit between December 1985 and September 1989 and reported never to have had homosexual contacts. Among 305 DUs, of whom 70% injected recently, the prevalence of HIV, HBV and HCV were 31%, 68% and 65% respectively. These prevalences were strongly interrelated and the same risk factors were found. The cumulative incidence of either HIV or HBV or HCV was 30% among prevalent HIV-negatives. Despite a previously reported reduction in risk behavior, only the HIV incidence tended to decrease initially, and after 1986 the incidences of HIV, HBV and HCV remained disturbingly high and stable (mean: 4, 9 and 10 per 100 person-years, respectively). As at present HBV appears to be transmitted more heterosexually than HIV in our study group and the HIV-epidemic may follow the HBV-epidemic in its transmission patterns, preventive activities targeted at both injecting and sexual behavior should be expanded.

Regional distribution and incidence of human papillomavirus infections among heterosexual men and women with multiple sexual partners: a prospective study.

OBJECTIVE--To assess prevalence, incidence and potential risk factors of human papillomavirus (HPV) infection among heterosexual men and women with multiple partners and to identify niches of HPV-infection. DESIGN--A prospective study of heterosexual men and women with multiple partners attending an STD clinic as participants in a study on HIV from May 1988 until January 1991. Routine STD examination and physical examination using colposcopy were performed, interviews with standardised questionnaires were administered. Specimens for HPV DNA detection by polymerase chain reaction were collected from multiple sites of the genital, anorectal and oral regions. In women cervical cytology was performed. SETTING--The STD Clinic of the Municipal Health Service of Amsterdam. PARTICIPANTS--162 women and 85 men entered the study, 110 women and 48 men were followed up. RESULTS--At entry of the study 37 (23%) women and 24 (28%) men were found positive for HPV DNA at any site. Only in one woman was oral presence of HPV DNA found during follow-up. Abnormal cervical cytology was observed in four women. In multivariate analysis, diagnosis of condylomata [odds ratio (OR) 5.61, 95% confidence interval (CI) 1.86 to 16.90)], reporting genital dermatological abnormalities (OR 3.72, 95% CI 1.38 to 9.99) and age (OR per year 0.93, 95% CI 0.88 to 0.99) predicted independently the presence of HPV DNA in women at entry of the study. In women 59 of the 99 (60%) HPV infections were observed in the genital region and 40% in the anorectal region: in men these figures were 65% and 35%, respectively. The incidence of HPV infection was 47.1 and 50.5 per 100 person-years for women and men respectively. At least 20/99 (20%) infections in women were intermediate or long persistent and only 3/48 (6%) HPV infections in men (P = 0.03). No risk factor for persistency could be determined, either in women or in men. CONCLUSIONS--HPV infection was found to be a multicentric genital and/or anorectal event both in women and men. The oral presence of HPV DNA was detected only once in one of the participants. In women persistent HPV infection was more common than in men. Independent predictors for presence of HPV DNA in women were diagnosis of condylomata acuminata, reporting genital dermatologic abnormalities and age. Incidence of HPV infection in women turned out to be 47.1 infections per 100 person-years and for men 50.5 per 100 person-years.

Risk reduction among intravenous drug users in Amsterdam under the influence of AIDS.

We evaluated the impact of a needle/syringe exchange program among 263 drug users in the period December 1985 to April 1988. Participants in this study were asked about their risk-behavior at three different visits. We found no increase in the proportion injecting drugs or in the frequency of intravenous drug use. A strong decrease in borrowing and lending of used needle/syringes was found and this behavioral change was not dependent on learning human immunodeficiency virus (HIV) serostatus. Although use of the exchange program increased over time, reduction in needle sharing was mainly an effect of the study with only a limited impact of the exchange program. We conclude that ample provision of needles and syringes is an important starting point but in itself not enough to produce the necessary drastic change in risk behavior. Intensive counseling of the drug user is also needed.

Decreasing STD incidence and increasing condom use among Chinese sex workers following a short term intervention: a prospective cohort study

Objective: To describe the impact of a repeating behavioural intervention focused on preventive education and provision of STD testing and treatment services to female sex workers. Methods: A prospective cohort study of 966 sex workers (first of its kind in China) was conducted in Guangzhou from March 1998 to October 1999. At each visit information was collected on sexual behaviour, condom use and knowledge about HIV transmission and condom use, education was given, STD were diagnosed, and treatment was provided free of charge. We evaluated trends in condom use, knowledge about HIV transmission and condom use, and STD incidences. Generalised estimating equations were applied to control for repeated measurements. Results: The proportion of consistent condom use increased from the intake through the third follow up visit (from 30% to 81%), as well as the proportion of having good knowledge on HIV transmission (4.3% to 98.6%) and condom use (23.6% to 79.3%). The incidence of gonorrhoea, trichomoniasis, and chlamydia decreased over each follow up visit; from 17.5/100 person years (PY), 22.4/100PY, 65.9/100PY at the first follow up visit to 5.1/100PY, 3.0/100PY, 16.1/100PY at the third follow up visit, for each STD respectively. Conclusions: STD care and prevention programmes targeting sex workers are feasible in China and, more importantly, intervention consisting of prevention education and STD care is likely to reduce unprotected sexual behaviour and STD incidence in this group at high risk for HIV and other STD infection.

The course of the HIV epidemic among intravenous drug users in Amsterdam, The Netherlands.

To determine if behavioral changes in intravenous drug users in Amsterdam have retarded the HIV (human immunodeficiency virus) epidemic in this group in recent years, we report that: HIV-antibody seroprevalence in annual samples of injectors has been constant over the years 1986-89; HIV-antibody incidence in a cohort of injectors appears to have decreased from 1986 to 1987 and stabilized after that until 1989; acute hepatitis B incidence in all drug users in Amsterdam declined rapidly between 1985-89. It is concluded that changes in drug use behavior so far appear to have resulted in a stabilization of the epidemic among injectors, at a level with a still disturbingly high incidence rate of 5-6 per 100 person-years.

Differences in clinical manifestations of genital chlamydial infections related to serovars.

OBJECTIVES: To study the association of serovars of Chlamydia trachomatis with clinical manifestations of genital tract infection and socio-demographic characteristics. METHODS: In 1986-88 the C trachomatis isolates from 159 heterosexual men and 116 women attending a sexually transmitted disease (STD) clinic were collected and typed accordingly. A medical history was recorded, a physical examination took place and samples were taken for laboratory diagnostics. RESULTS: Serovars E, F and D were the most common for both men (75%) and women (67%). Men infected with serovars of the C-complex had more often a history of STD (p = 0.06). The opposite was demonstrated in women (p = 0.07). In addition, women younger than 18 years at first intercourse were more often infected with C-complex serovars (p = 0.05). For men, the serovars F/G less often produced symptoms of urethral discharge (p = 0.01) than the serovars of the B-complex and C-complex and were less often associated with the presence of 10 or more leukocytes in a Gram-stained smear (p = 0.04). CONCLUSIONS: In this study, infections with serovars F and G caused less obvious symptoms and signs of inflammation in men; in women no differences were found in the clinical manifestation of infections with different serovars.

Prevalence of thrombocytopenia in HIV-infected and non-HIV infected drug users and homosexual men

Summary. We studied the prevalence and risk factors for thrombocytopenia among 299 drug users and 461 homosexual men. The prevalence of thrombocytopenia was 3·3% in HIV‐negative homosexual men, 8·7% in HIV‐negative drug users, 16·4% in HIV‐positive homosexual men, and 36·9% in HIV‐positive drug users. With multivariate logistic regression HIV‐seropositivity (odds ratio 3·3), a history of injecting drugs (OR 3·9), an increased number of lymphocytes (OR 0·44), an increased number of neutrophils (OR 0·53) and a larger mean platelet volume (OR 2·8) were independently and significantly associated with thrombocytopenia. The results obtained with linear regression analysis were consistent with the results of the logistic regression. The higher prevalence of thrombocytopenia among drug users was related to a history of intravenous drug use but not to recent injecting. The mechanisms causing thrombocytopenia among HIV‐positives and HIV‐negatives seem to be related, but HIV‐infection seems to enhance thrombocytopenia in an independent way.

Evaluation of the hepatitis B antenatal screening and neonatal immunization program in Amsterdam, 1993–1998

In the enhanced antenatal hepatitis B screening and neonatal immunization program in Amsterdam, 691 hepatitis B surface antigen (HBsAg) positive expectant mothers were reported in the period 1993-1998. The coverage of the screening was calculated at 97%. HBsAg-prevalence was high in women from Ghana and South-East Asia, and lowest in Dutch women. Hepatitis B immune globulin (HBIg) was administered within 24h to 95.9% of the neonates; 99.7% completed the vaccination series. About 6 weeks after the third vaccination the titer antiHBs was > or =100 IU/l in 85% of children; in 12% the titers were 10-100 IU/l; 3% had titers <10 IU/l, of whom 3/521 initially had HBsAg. Low birth weight (OR 3.77), being a boy (OR 1.64) and country of origin were predictors of low postvaccination titers. Coordinated by 0.5 full time equivalent (fte) additional staff, the program was relatively cheap and successful.

HIV infection and STD in drug addicted prostitutes in Amsterdam: potential for heterosexual HIV transmission.

To assess the potential role of drug using prostitutes in the heterosexual transmission of human immunodeficiency virus (HIV), 117 prostitutes, recruited from December 1985 to November 1987 at a weekly evening sexually transmitted diseases (STD) clinic for drug using prostitutes only, were studied for the prevalence of HIV and STD. Intravenous drug use was reported by 96 (82%) of the women. Antibody to HIV was found in 35/117 (30%) women, all but one of whom had been using drugs intravenously. Most (73, 62%) of the prostitutes reported having had more than 2000 clients each in the preceding five years. In the six months preceding enrollment to the study they had practised mainly vaginal (106/117) and orogenital (82/117) intercourse; 90% (105/117) reported frequent use of condoms in vaginal intercourse and 65% (68/105) in orogenital intercourse. Despite frequent condom use, 81% (84/104) contracted one or more STD in this period. Considering the high incidence of HIV and STD and the finding by others that the presence of STD may facilitate transmission of HIV, we conclude that the potential for HIV transmission from these prostitutes to their clients (and vice versa) was clearly present.

HIV prevalence and risk behaviour among prostitutes and clients in Amsterdam: migrants at increased risk for HIV infection.

OBJECTIVES--To study groups of prostitutes and clients of prostitutes in order (i) to determine HIV prevalence and sexual risk behaviour, (ii) to determine differences between samples recruited within and outside a clinic for sexually transmitted diseases (STD) and (iii) to determine correlates of inconsistent condom use (ICU) among both groups. DESIGN--Participants were interviewed and anonymously tested for HIV-antibody; approximately half were recruited at a clinic for sexually transmitted diseases (STD) and half at prostitute working places. SETTING--An STD clinic and prostitute working places in Amsterdam in 1991. SUBJECTS--201 female prostitutes without a history of injecting drugs and 213 male clients of female prostitutes. MAIN OUTCOME MEASURES--antibodies to HIV, consistency of condom use in commercial vaginal contacts in the preceding 6 months. RESULTS--HIV prevalence was low: three prostitutes (1.5%; 95% CI 0.5-4.6%) and one client (0.5%; 95% CI 0.1-3.3%) were infected. All three HIV positive prostitutes originated from AIDS-endemic countries, came to the Netherlands only recently and were recruited outside the STD clinic. Large differences between subgroups resulted from the two recruitment methods: while clients of prostitutes with relatively high risk behaviour were strongly represented among the STD clinic sample, high risk prostitutes were underrepresented in this sample. Consistent condom use (with 100% of contacts) was reported by 66% of prostitutes and 56% of clients of prostitutes. Inconsistent condom use was found to be high among prostitutes who had migrated from Latin America and among migrant clients of prostitutes. CONCLUSIONS--When monitoring HIV infection one must take into account imported cases. HIV prevention efforts should be particularly focused at prostitutes from Latin America and at clients of prostitutes who migrated to the Netherlands.