Sexual mixing patterns and sex-differentials in teenage exposure to HIV infection in rural Zimbabwe

Transmission of HIV-1 infection in sub-Saharan Africa and effect of elimination of unsafe injections

During the past year, a group has argued that unsafe injections are a major if not the main mode of HIV-1 transmission in sub-Saharan Africa. We review the main arguments used to question the epidemiological interpretations on the lead role of unsafe sex in HIV-1 transmission, and conclude there is no compelling evidence that unsafe injections are a predominant mode of HIV-1 transmission in sub-Saharan Africa. Conversely, though there is a clear need to eliminate all unsafe injections, epidemiological evidence indicates that sexual transmission continues to be by far the major mode of spread of HIV-1 in the region. Increased efforts are needed to reduce sexual transmission of HIV-1.

Understanding the uneven spread of HIV within Africa: comparative study of biologic, behavioral, and contextual factors in rural populations in Tanzania and Zimbabwe

BACKGROUND

Large differences in the spread of HIV have been observed within sub-Saharan Africa.

GOAL

The goal was to identify factors that could explain differences in the spread of HIV within sub-Saharan African populations.

STUDY DESIGN

Ecologic comparison of data from population-based surveys in high and relatively low HIV prevalence rural areas in Zimbabwe, Manicaland, and Tanzania, Kisesa.

RESULTS

HIV prevalence in Manicaland and Kisesa was 15.4% and 5.3% in men aged 17-44 years and 21.1% and 8.0% in women aged 15-44 years (odds ratios, 3.3 and 3.1, respectively). Marriage is later, spatial mobility more common, cohabitation with marital partners less frequent, education levels are higher, and male circumcision is less common in Manicaland. However, adjustment for differences in these factors increased the odds ratios for HIV infection in Manicaland versus Kisesa to 6.9 and 4.8 for men and women, respectively. Sexually transmitted infection levels were similar, but syphilis was only common in Kisesa. Respondents in Kisesa started sex earlier and reported more sexual partners. Age differences between partners were similar in the 2 locations.

CONCLUSION

Substantial differences exist between the contemporary sociodemographic profiles of rural Manicaland and Kisesa. However, these differences did not translate into measurable differences in the biologic or behavioral factors for which data were available and did not explain the much higher HIV prevalence found in Manicaland. These findings might reflect more extensive AIDS-selective mortality and behavior change or greater bias in reporting of sexual behavior in Zimbabwe.

Does knowing someone with AIDS affect condom use? An analysis from South Africa

Prior research in Africa suggests that personally knowing someone with HIV/AIDS or who died of AIDS (PWA) may positively influence HIV-preventive behaviors such as condom use, by countering denial and increasing perceived risk. This article uses data from the 1998 South Africa Demographic and Health Survey (DHS) of women to examine this hypothesis in South Africa, where AIDS mortality is high. Logistic regression was applied to assess whether knowing a PWA was associated with condom use, net of the effects of possible confounders. Contrary to previous findings, analyses showed no association between condom use and having known a PWA. Condom use was strongly associated with knowledge that condoms can prevent HIV/AIDS, sex with a non-marital partner, higher education level, younger age, and urban residency. Findings suggest that communities should expand preventive efforts given the current level of AIDS mortality. Campaigns must reinforce messages that condoms are effective, and reach rural, less educated women, for whom HIV risk is high in South Africa.

HIV and population dynamics: a general model and maximum-likelihood standards for east Africa

In high-prevalence populations, the HIV epidemic undermines the validity of past empirical models and related demographic techniques. A parsimonious model of HIV and population dynamics is presented here and fit to 46,000 observations, gathered from 11 East African populations. The fitted model simulates HIV and population dynamics with standard demographic inputs and only two additional parameters for the onset and scale of the epidemic. The underestimation of the general prevalence of HIV in samples of pregnant women and the fertility impact of HIV are examples of the dynamic interactions that demographic models must reproduce and are shown here to increase over time even with constant prevalence levels. As a result, the impact of HIV on population growth appears to have been underestimated by current population projections that ignore this dynamic.

Age differences in sexual partners and risk of HIV-1 infection in rural Uganda

OBJECTIVES

To assess whether differences in age between sexual partners affect the risk of HIV infection in female adolescents and young adults.

METHODS

A total of 6177 ever sexually active women aged 15 to 29 years completed a sociodemographic and sexual behavior questionnaire and provided a blood sample for HIV-1 serology. The age difference between partners was categorized as men 0 to 4 years older (referent group), 5 to 9 years older and 10 or more years older. HIV prevalence and incidence were assessed, and adjusted RR was estimated by multivariate regression.

RESULTS

Prevalent HIV-1 infection in female participants increased with older male sexual partners. Among women aged 15 to 19 years, the adjusted risk of HIV infection doubled (RR = 2.04; 95% CI: 1.29-3.22) among those reporting male partners 10 or more years older compared with those with male partners 0 to 4 years older; among women 20 to 24 years of age, the RR was 1.24 (95% CI: 0.96-1.60). The attributable fraction (exposed) of prevalent HIV infection in women aged 15 to 24 years associated with partners 10 or more years older was 9.7% (95% CI: 5.2-14.0). HIV incidence did not increase with differences in age of partners.

CONCLUSION

The age difference between young women and their male partners is a significant HIV risk factor, suggesting that high HIV prevalence in younger women is caused, in part, by transmission from older male partners.

Opportunity for prevention of HIV and sexually transmitted infections in Kenyan youth: results of a population-based survey

BACKGROUND

Data from sentinel serosurveillance are useful to estimate HIV infection in populations but may not be representative of the general population. General population-based surveys attempt to avoid selection bias and are the most appropriate for tracking changes in exposure to risk of HIV infection over time and assessing changes in behavior following prevention campaigns.

OBJECTIVES

To provide baseline data for targeted sexually transmitted infection (STI) and HIV infection prevention interventions by studying parameters of sexual behavior and knowledge of HIV infection and STIs, measuring health-seeking behavior related to STIs, and measuring gonorrhea, Chlamydia, syphilis, and HIV-1 prevalences.

DESIGN

Population-based survey with stratified sampling by age group from randomly selected households in a suburb of Mombasa, Kenya.

METHODS

A standard questionnaire was administered to 1497 consenting adults between the ages of 15 and 49 years who lived in randomly selected households. Urine and blood samples were obtained for the estimation of gonorrhea, chlamydial infection, syphilis, and HIV-1 infection prevalences.

RESULTS

Sexual activity in the past 12 months was limited to one partner in all age groups for most sexually active men (68%) and women (88%). More men than women reported two or more partners in the past 12 months (23% vs. 5%, respectively). Almost one half of those persons in the 15- to 19-year-old age group (56% of boys and 48% of girls) were sexually active. Condom use was low with all sexual partners, more so for women than for men. Reported STI symptoms in the past 12 months were high for both men and women. Knowledge of STI symptoms and HIV infection was present but incomplete. Overall HIV seroprevalence was 10.8%, with significantly higher rates among women (13.7%) than among men (8.0%). HIV seroprevalence in the 15- to 19-year-old age group was 3.2%. Female gender, Protestant religion, Catholic religion, and being divorced, separated, and widowed were significantly associated with HIV seroprevalence. Prevalences of gonorrhea, chlamydial infection, and syphilis were 0.9%, 1.5%, and 1.3%, respectively.

CONCLUSIONS

This study emphasizes the vulnerability of young adults, in particular young women, to HIV infection and the need for intensive interventions in this group. The low use of condoms, incomplete knowledge of HIV infection and STIs, the high number of reported STIs, and the relatively low HIV-1 seroprevalence among the 15- to 19-year-old group indicate a large need for intensive STI and HIV infection prevention programs, especially for the 15- to 19-year-old age group.

Methods to reduce social desirability bias in sex surveys in low-development settings: experience in Zimbabwe

BACKGROUND

Social desirability bias hampers measurement of risk behavior for acquiring STDs and evaluation of control interventions. More confidential data collection methods reduce this bias in Western countries but generally require technology not available in less developed settings. GOAL The goal of this report was to describe and evaluate an informal, confidential, low-technology method-Informal Confidential Voting Interviews (ICVIs)-for collecting sexual behavior data in less developed settings.

STUDY DESIGN

Reports of multiple sex partners by sexually active, basic-literate, population-based survey participants in rural Zimbabwe randomly assigned to ICVIs and face-to-face interviews (FTFIs) were compared.

RESULTS

Ninety-two percent of respondents (n = 7,823) were sufficiently literate for ICVIs. Error rates were low but higher than in FTFIs. More male and female ICVI respondents interviewed reported multiple current sex partners (OR = 1.33 and 5.24, respectively) and multiple partners in the past month (OR = 1.71 and 2.92) and the past year (OR = 1.35 and 1.97).

CONCLUSION

The ICVI method appears to reduce bias but requires further evaluation to assess viability and effect in alternative settings.