Michel Caraël

Why do young women have a much higher prevalence of HIV than young men? A study in Kisumu, Kenya and Ndola, Zambia

Objective: To examine the factors responsible for the disparity in HIV prevalence between young men and women in two urban populations in Africa with high HIV prevalence. Design: Cross-sectional survey, aiming to include 1000 men and 1000 women aged 15-49 years in Kisumu, Kenya and Ndola, Zambia. Methods: Participants were interviewed and tested for HIV and other sexually transmitted infections. Analyses compared the marital and non-marital partnership patterns in young men and women, and estimated the likelihood of having an HIV-infected partner. Results: Overall, 26% of individuals in Kisumu and 28% in Ndola were HIV-positive. In both sites, HIV prevalence in women was six times that in men among sexually active 15-19 year olds, three times that in men among 20-24 year olds, and equal to that in men among 25-49 year olds. Age at sexual debut was similar in men and women, and men had more partners than women. Women married younger than men and marriage was a risk factor for HIV, but the disparity in HIV prevalence was present in both married and unmarried individuals. Women often had older partners, and men rarely had partners much older than themselves. Nevertheless, the estimated prevalence of HIV in the partners of unmarried men aged under 20 was as high as that for unmarried women. HIV prevalence was very high even among women reporting one lifetime partner and few episodes of sexual intercourse. Conclusions: Behavioural factors could not fully explain the discrepancy in HIV prevalence between men and women. Despite the tendency for women to have older partners, young men were at least as likely to encounter an HIV-infected partner as young women. It is likely that the greater susceptibility of women to HIV infection is an important factor both in explaining the male-female discrepancy in HIV prevalence and in driving the epidemic. Herpes simplex virus type 2 infection, which is more prevalent in young women than in young men, is probably one of the factors that increases womens susceptibility to HIV infection.

Change in sexual behaviour and decline in HIV infection among young pregnant women in urban Uganda.

Objective:To describe sexual behaviour that may partly explain a decline in HIV seroprevalence in pregnant women in urban settings in Uganda, East Africa. Settings:Two major urban districts in Uganda. Methods:Repeated population-based behavioural surveys in 1989 and 1995, and repeated HIV serological surveys in consecutive pregnant women attending antenatal clinics from 1989 to 1995. Results:During the study period, a 2-year delay in the onset of sexual intercourse among youths aged 15–24 years and a 9% decrease in casual sex in the past year in male youths aged 15–24 years were reported. Men and women reported a 40% and 30% increase in experience of condom use, respectively. In the same study area, over the same period, there was an overall 40% decline in the rates of HIV seroprevalence among pregnant women attending antenatal clinics. It can be hypothesized that the observed declining trends in HIV correspond to a change in sexual behaviour and condom use, especially among youths. Conclusions:This is the first report of a change over a period of 6 years in male and female sexual behaviour, assessed at the population level, that may partly explain the observed decline in HIV seroprevalence in young pregnant women in urban Uganda. This result should encourage AIDS control programmes to pursue their prevention activities.

HIV infection among youth in a South African mining town is associated with herpes simplex virus-2 seropositivity and sexual behaviour.

ObjectivesTo determine the seroprevalence of HIV and herpes simplex virus-2 (HSV-2) by age and gender among young people aged 14-24 years in a South African town and to identify risk factors for HIV infection. DesignA community-based, cross-sectional study was conducted on a random sample of men (n = 723) and women (n = 784) living in a township in the Carletonville district of South Africa. MethodsPotential demographic and behavioural risk factors associated with HIV were recorded by questionnaire and biological tests were performed on serum and urine. Data analysis was performed using multivariate logistic regression. ResultsAmong men and women the prevalence of HIV infection was 9.4 and 34.4%, respectively, and of positive HSV-2 serology was 17.0 and 53.3%, respectively. Among 24-year-old women the prevalence of HIV was 66.7% [95% confidence interval (CI), 54.6–77.3%]. HSV-2 seropositivity was a strong independent risk factor for HIV infection with odds ratios of 5.3 (95% CI, 2.7–10.3) for men and 8.4 (95% CI, 4.9–14.2) for women. There was no independent effect of age at first sex or serological markers of other sexually transmitted infections on HIV infection. ConclusionsHIV infection among young women increases rapidly after the onset of sexual activity and reaches extremely high levels by 24 years of age. These findings suggest that rates of HIV transmission from men to women are high and that HSV-2 plays a major role in the spread of HIV in this population.

Female prostitutes: a risk group for infection with human T-cell lymphotropic virus type III.

In July, 1984 33 female prostitutes in Rwanda and 25 male customers of prostitutes were assessed clinically and for their T-lymphocyte subsets and frequency of antibodies to human T-cell lymphotropic virus type III (HTLV-III). 27 healthy males who denied contact with prostitutes, 33 healthy women who were not prostitutes, and 51 Rwandese prostitutes seen in 1983 served as controls. Only 6 prostitutes were symptom-free (group I), 13 had unexplained generalised lymphadenopathy (LAP) (group II), and 14 had LAP and constitutional symptoms (group III). Mean OKT4/OKT8 ratio in groups II and III was significantly lower than that in group I or in female controls. HTLV-III antibodies were detected in 29 of 33 prostitutes, 4 female controls, 7 male customers, and 2 male controls. In male customers, HTLV-III seropositivity increased according to the number of different sexual partners per year. This study suggests that in Central Africa prostitutes are a high-risk group for HTLV-III infection.

Concurrent sexual partnerships and HIV prevalence in five urban communities of sub-Saharan Africa.

ObjectiveTo estimate parameters of concurrent sexual partnerships in five urban populations in sub-Saharan Africa and to assess their association with levels of HIV infection and other sexually transmitted infections (STI). MethodsData were obtained from a multicentre study of factors which determine the differences in rate of spread of HIV in five African cities. Consenting participants were interviewed on sexual behaviour and at four of the five sites also provided a blood and a urine sample for testing for HIV and other STI. Data on sexual behaviour included the number of partnerships in the 12 months preceding the interview as well as the dates of the start and end of each partnership. Summary indices of concurrent sexual partnerships – some of which were taken from the literature, while others were newly developed – were computed for each city and compared to HIV and STI prevalence rates. ResultsA total of 1819 adults aged 15–49 years were interviewed in Dakar (Senegal), 2116 in Cotonou (Benin), 2089 in Yaoundé (Cameroon), 1889 in Kisumu (Kenya) and 1730 in Ndola (Zambia). Prevalence rates of HIV infection were 3.4% for Cotonou, 5.9% for Yaoundé, 25.9% for Kisumu and 28.4% for Ndola, and around 1% for Dakar. The estimated fraction of sexual partnerships that were concurrent at the time of interview (index k) was relatively high in Yaoundé (0.98), intermediate in Kisumu (0.44) and Cotonou (0.33) and low in Ndola (0.26) and in Dakar (0.18). An individual indicator of concurrency (iic) was developed which depends neither on the number of partners nor on the length of the partnerships and estimates the individual propensity to keep (positive values) or to dissolve (negative values) on-going partnership before engaging in another one. This measure iic did not discriminate between cities with high HIV infection levels and cities with low HIV infection levels. In addition, iic did not differ significantly between HIV-infected and uninfected people in the four cities where data on HIV status were collected. ConclusionWe could not find evidence that concurrent sexual partnerships were a major determinant of the rate of spread of HIV in five cities in sub-Saharan Africa. HIV epidemics are the result of many factors, behavioural as well as biological, of which concurrent sexual partnerships are only one.

Commercial sex and the spread of HIV in four cities in sub-Saharan Africa.

Objective: To examine whether commercial sex transactions were more common and/or transmission between sex workers and clients more efficient in two African cities with high HIV prevalence (Kisumu, Kenya and Ndola, Zambia) compared with two with relatively low HIV prevalence (Cotonou, Benin and Yaoundé, Cameroon). Methods: Data on sexual behaviour, HIV and sexually transmitted infections were collected from representative samples of around 300 female sex workers in each city. Sexual behaviour data from a population-based study of around 1000 men aged 15-49 in each city were used to estimate the extent of contact with sex workers. Results: The number of sex workers per 1000 males was highest in Kisumu and Ndola, but other estimates of the extent or characteristics of sex work contact showed no consistent differences between high or low prevalence cities. HIV prevalence among sex workers was 75% in Kisumu, 69% in Ndola, 55% in Cotonou and 34% in Yaoundé. The prevalence of genital ulceration and trichomoniasis was higher among sex workers in Kisumu and Ndola but no clear pattern was seen for the other sexually transmitted infections. Around 70% of sex workers in Cotonou reported use of a condom with the last client, markedly higher than in the other cities. Conclusions: Although sex work is likely to have played an important role in the spread of HIV in all four cities, differences in present patterns of sex work do not appear to explain the differential spread of HIV. However, high levels of condom use among sex workers may have slowed the spread from sex workers to the general population in Cotonou, highlighting the importance of interventions among sex workers and their clients.

Knowledge Attitudes. and Perceived Risk of AIDS Among Urban Rwandan Women - Relationship to HIV Infection and Behavior Change

We examined factors associated with perceived risk of AIDS, behavior change, and HIV infection in a representative sample of 1458 child-bearing urban women in Rwanda, central Africa. Although 68% of women reported only one lifetime partner, and the majority (87%) lived with a husband or steady partner, the prevalence of HIV antibodies was still high (32%). Before receiving their HIV test results, the women completed a questionnaire about AIDS knowledge, attitudes, and practices. Knowledge about HIV transmission was high, with 96-98% of women correctly identifying the three primary routes of infection. However, only 16% of women reported taking any action to avoid AIDS in the previous year, and most (11%) had done so merely by asking their male partners to change their behavior. Only 7% of women had ever tried condoms, and many (68%) thought they could be dangerous to use. Women who perceived themselves at risk of AIDS (57%) were more likely to report changing behavior; they were also more likely to be infected with HIV. Other factors associated with behavior change included having known someone with AIDS, having discussed AIDS with a male partner, and believing that condoms are not dangerous. Future interventions should enhance perception of risk, encourage male sexual partners to reduce risky behavior, and increase familiarity with condoms.

Postnatal transmission of HIV from mother to child

2 cases of post-partum transmission of human immunodefficiency virus (HIV) from mother to infant from Kigali Rwanda are reported. All results were confirmed by western blot tests. 1) A 23-year-old woman with no history of extramarital sexual contact blood transfusions drug abuse or injections during pregnancy experienced severe bleeding during childbirth and was transfused with 2 units blood one of which had been drawn from a donor who later proved to be seropositive. The child sickened and died at 19 months of chronic diarrhea after having presented with failure to thrive generalized lymphadenopathy oral thrush and hepatomegaly moderate psychomotor delay and lobar pneumonia on chest x-ray. At 15 months post-partum the mother showed mild lymphocytosis and had antibodies to HIV. She had no dermatitis and breast-fed the child without problems until she died. 2) The 2nd case of a boy was quite similar: a postpartum transfusion from a donor who later prove to be seropositive was the most likely source of the mothers HIV infection. The child in question was still being breast fed at 15 months having begun to show symptoms of HIV infection at 5 months of age. A 30-month-old sibling was thriving and seronegative. In both cases the fathers were seronegative. Given the length of time the children had been breast fed and past studies showing the presence of HIV in breast milk as well as colostrum breast milk appears to be the most likely source of the infection in these cases. They were 2 cases out of 107 pediatric cases of AIDS and AIDS-related complex studied over 2 years. The results do not indicate a need to discourage mothers from breastfeeding but do underline the need to enforce measures to avoid contamination of banked breast milk.

Educational level is associated with condom use within non-spousal partnerships in four cities of sub-Saharan Africa.

BackgroundRates of condom use in sub-Saharan Africa have remained too low to curb HIV/sexually transmitted disease (STD) epidemics. A better understanding of the main determinants of condom use would aid promotion. MethodsCross-sectional population surveys were conducted in four cities in sub-Saharan Africa: Yaoundé, Cameroon; Cotonou, Benin; Ndola, Zambia; and Kisumu, Kenya. In each city, the aim was to interview a random sample of 1000 men and 1000 women aged 15–49 years, including questions on characteristics of non-spousal partnerships in the past 12 months. ResultsData on condom use were available for 4624 non-spousal partnerships. In the four cities, the proportion of partnerships in which condoms were used always or most of the time ranged from 23.8 to 33.5% when reported by men and from 10.7 to 25.9% when reported by women. Based on the reports from men, condom use was associated with higher educational level of the male partner in Yaoundé [adjusted odds ratio (aOR) = 1.76] and Ndola (aOR = 2.94) and with higher educational level of the female partner in Cotonou (aOR = 2.36) and Kisumu (aOR = 2.76). Based on the reports from women, condom use was associated with higher educational level of the female partner in Kisumu (aOR = 2.60) and Ndola (aOR = 4.50) and with higher educational level of the male partner in Yaoundé (aOR = 3.32). Associations with other determinants varied across cities and for men and women. ConclusionsEducation was found to be a key determinant of condom use in all four cities. This suggests that educational level increases response to condom promotion and highlights the need for special efforts to reach men and women with low educational attainment.

To stem HIV in Africa, prevent transmission to young women.

Over the years community-based studies have shown that higher proportions of young women (15-19 years) in Africa are already infected with HIV compared with their male counterparts. This is likely because non-response in HIV surveys is higher in men than women and those who are repeatedly absent or who refuse clinical testing may be more likely to be HIV infected. Moreover HIV is more easily transmitted from men to women than vice versa. Patterns of sexual mixing may also account for differences in the infection levels between men and women evidenced in the frequent sexual relationships between younger women and older men. Men also appear to be less to use condoms with young female partners. In this perspective the success in cutting back the devastation caused by HIV and AIDS in east and southern Africa depends upon the successful prevention of transmission of HIV to young women while focusing on both men and women. Thus prevention programs provided to young women and their older partners in a high-HIV prevalence epidemic should aim to: 1) reduce early exposure to risky sex 2) reduce likelihood of transmission per sexual act and 3) reduce age difference between partners.