Heterosexual transmission of HIV: a global view a decade later

The incidence of HIV among women recruited during late pregnancy and followed up for six years after childbirth in Zimbabwe

Background

HIV incidence is a useful tool for improving the targeting of populations for interventions and assessing the effectiveness of prevention strategies. A study in Harare, Zimbabwe reported cumulative incidences of 3.4% (3.0-3.8) and 6.5% (5.7-7.4) among post-partum women followed for 12 and 24 months respectively between 1997 and 2001. According to a Government report on HIV the prevalence of HIV fell from about 30% in 1999 to 14% in 2008. The purpose of this study was to determine the incidence of HIV-1 among women enrolled during late pregnancy and followed for six years after childbirth and to identify risk factors associated with acquisition of HIV.

Methods

HIV-uninfected pregnant women around 36 weeks gestation were enrolled from primary health care clinics in peri-urban settlements around Harare and followed-up for up to six years after childbirth. At every visit a questionnaire was interview-administered to obtain socio-demographic data and sexual history since the previous visit. A genital examination was performed followed by the collection of biological samples.

Results

Of the 552 HIV-uninfected women 444 (80.4%) were seen at least twice during the six years follow-up and 39 acquired HIV, resulting in an incidence (95% CI) of 2.3/100 woman-years-at-risk (wyar) (1.1-4.1). The incidence over the first nine months post-partum was 5.7/100 wyar (3.3-8.1). A greater proportion of teenagers (15.3%) contributed to a high incidence rate of 2.9/100 (0.6-8.7) wyar. In multivariate analysis lower education of participant, RR 2.1 (1.1-4.3) remained significantly associated with HIV acquisition. Other risk factors associated with acquisition of HIV-1 in univariate analysis were young age at sexual debut, RR 2.3, (1.0-5.6) and having children with different fathers, RR 2.7(1.3-5.8). Women that knew that their partners had other sexual partners were about four times more likely to acquire HIV, RR 3.8 (1.3-11.2).

Conclusion

The incidence of HIV was high during the first nine months after childbirth. Time of seroconversion, age and educational level of seroconverter are important factors that must be considered when designing HIV intervention strategies.

Socio-behaviour challenges to phase III HIV vaccine trials in Sub-Saharan Africa

BACKGROUND

A number of countries in sub-Saharan Africa are preparing for HIV vaccine efficacy trials. Social and behavioural factors related to HIV transmission require examination in each setting where these trials are considered. As part of this, several countries have also recently begun preparatory research investigating relevant social and behavioural issues. There is a need for a review of the literature to help focus such research efforts in Sub-Saharan Africa.

OBJECTIVES

To examine key social and behavioural issues that may impact on the conduct of HIV vaccine efficacy trials in sub-Saharan Africa.

DESIGN

Literature review

METHODS

Major databases (PubMed, PsychInfo, EBSCOhost, and AIDSline) were searched for literature that discussed social and behavioural issues related to HIV vaccine trials. Three areas are highlighted as being particularly significant for HIV vaccine research: (1) willingness to participate in future HIV vaccine efficacy trials, (2) retention of participants in studies, and (3) sexual risk reporting during trials. For each of these topics, major findings from both developed and developing countries are described and avenues for further research are discussed.

RESULTS

There are few data from Sub-Saharan Africa regarding willingness to participate in HIV vaccine trials. Data on participant retention rates varies widely, and maintaining large cohorts of individuals within Phase III trials presents an important challenge. In addition, the possible impact of trial participation on sexual disinhibition, and response bias on sexual risk-reporting remain as issues for HIV vaccine trials in African contexts.

CONCLUSION

Social and behavioural research forms an important part of preparations for HIV vaccine efficacy trials, and there is a clear need for more research of this type in Sub-Saharan Africa. Innovative approaches are required to address issues such as willingness to participate in vaccine research, participant retention during efficacy trials, and the accurate reporting by participants of sexual risk behaviours.

Risk perception and counselling among HIV-positive women in São Paulo, Brazil

This study of HIV-positive women at a clinic for HIV/AIDS in São Paulo examined their risk perception for HIV before they had learned of their diagnosis and their experiences with pre- and post-test counselling. A sample of 148 women was interviewed regarding demographics, HIV risk factors and risk perception, pre- and post-test counselling, and sexual and reproductive conduct. The majority (77%) had been infected by their partners--37% by an injecting drug user partner. More than half (53%) did not perceive themselves at risk before learning of their HIV status and, of 68 who had perceived themselves at risk, 29% did so only after their partners became ill. The majority (64%) did not receive any kind of pre-test counselling. Post-test counselling was reported by 83% but 14% reported being mishandled by a physician in the process. Findings suggest the importance of prevention efforts to reduce women's barriers to learning about HIV status and the necessity of improving the quality of pre- and post-test counselling.

Rates of HIV-1 transmission within marriage in rural Uganda in relation to the HIV sero-status of the partners

OBJECTIVE

To assess the efficacy of transmission of HIV-1 within married couples in rural Uganda according to the sero-status of the partners.

DESIGN

Estimation of HIV incidence rates for 2200 adults in a population cohort followed for 7 years comparing male-to-female with female-to-male transmission and sero-discordant with concordant sero-negative couples.

METHODS

Each year, adults (over 12 years of age) resident in the study area were linked to their spouses if also censused as resident. The HIV sero-status was determined annually.

RESULTS

At baseline 7% of married adults were in sero-discordant marriages and in half of these the man was HIV-positive. Among those with HIV-positive spouses, the age-adjusted HIV incidence in women was twice that of men (rate ratio (RR) = 2.2 95% confidence interval (CI) 0.9-5.4) whereas, among those with HIV-negative spouses, the incidence in women was less than half that of men (RR = 0.4, 95% CI 0.2-0.8). The age-adjusted incidence among women with HIV-positive spouses was 105.8 times (95% CI 33.6-332.7) that of women with HIV-negative spouses, the equivalent ratio for men being 11.6 (95% CI 5.8-23.4).

CONCLUSION

Men are twice as likely as women to bring HIV infection into a marriage, presumably through extra-marital sexual behaviour. Within sero-discordant marriages women become infected twice as fast as men, probably because of increased biological susceptibility. Married adults, particularly women, with HIV-positive spouses are at very high risk of HIV infection. Married couples in this population should be encouraged to attend for HIV counselling together so that sero-discordant couples can be identified and advised accordingly.