Antiretroviral prophylaxis: a defining moment in HIV control

A defining moment in the global AIDS response has been reached. The discourse is no longer about HIV prevention or HIV treatment; it is now about HIV control through the implementation of antiretrovirals as key components of combination interventions. Barely a year ago, visions of HIV control would have been considered far-fetched. The impetus for this change in mindset, which has been building since the XVIII International AIDS Conference in Vienna last year, emanates from the compelling evidence that antiretroviral drugs prevent HIV infection in the general heterosexual population, which is released this week and presented at the 6th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention in Rome by the Partners PrEP and Botswana TDF2 trials

Drug concentrations after topical and oral antiretroviral pre-exposure prophylaxis: implications for HIV prevention in women

The early closure of a clinical trial assessing the effectiveness of oral antiretroviral pre-exposure prophylaxis (PrEP) in women, FEM-PrEP, is a substantial setback for HIV prevention. Expectations of this trial were high in view of favourable results from the pre-exposure prophylaxis initiative (iPrEX) trial, which studied the same drug and dosing strategy in men who have sex with men, and the Centre for the AIDS Programme of Research in South Africa (CAPRISA 004) trial,3 which tested tenofovir gel (a topical PrEP formulation) in heterosexual women. As a result, the interim FEM-PrEP trial results, announced on April 18, 2011, which showed no protection against HIV infection, were disappointing. Using publicly available information and data from other PrEP studies, we offer a potential explanation for the results of the FEM-PrEP trial

Stigma impedes AIDS prevention

Thirty years since the first cases of AIDS were described, there is much to celebrate regarding progress in the treatment and prevention of the disease. Within the past year alone, several studies have revealed that antiretroviral drugs can prevent the sexual transmission of HIV. Yet worldwide, many people who are potentially exposed to the virus avoid finding out whether they carry it, or deny that they are at risk of contracting it. Unless people establish whether they are infected, they will not be able to be adopt the most appropriate preventive measures. As scientists and clinicians, our ability to overcome this denialism will determine whether we ultimately succeed in using combinations of all the preventive and therapeutic tools now available to slow, and eventually stop, the HIV/AIDS pandemic

Contraceptive Choices, Pregnancy Rates, and Outcomes in a Microbicide Trial

OBJECTIVE: Women who become pregnant during the conduct of biomedical human immunodeficiency virus prevention trials are taken off the study product for safety reasons. High pregnancy rates can compromise statistical integrity in these trials. The comprehensive contraceptive curriculum developed for the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 004 trial was evaluated for its ability to enhance contraceptive uptake, reduce pregnancy rates, and preserve statistical integrity. METHODS: Contraceptive- and pregnancy-related eligibility criteria were specified in the protocol. We enrolled women who opted for a nonbarrier method of contraceptive and provided hormonal contraceptives onsite at no cost. At each monthly study visit, we provided pregnancy prevention counseling and performed pregnancy testing. Study product was withheld on pregnancy diagnosis, but women continued with monthly follow-up. RESULTS: Contraceptive use was high throughout the study with 100% uptake at baseline and 94.71% use after a mean of 18 months follow-up at exit. Injectable progestins, particularly medroxyprogesterone acetate, remained the preferred choice of contraceptive. After 30 months of follow-up, 54 pregnancies were reported out of 889 participants, giving a pregnancy incidence rate of 3.95 per 100 woman-years (95% confidence interval 2.96-5.17). Of all pregnancies, two thirds (64.81%) resulted in a full-term live birth, whereas 18.52% and 11.11% pregnancies culminated as miscarriage and terminated pregnancies, respectively. There were no congenital anomalies in the early neonatal period. Pregnancies resulted in 1.56% of woman-years of study follow-up lost as a result of temporary product withdrawal. CONCLUSION: The CAPRISA 004 contraceptive curriculum was an effective strategy for maintaining low pregnancy rates, thereby minimizing product withdrawal and loss of follow-up time

Relationship between levels of inflammatory cytokines in the genital tract and CD4+ cell counts in women with acute HIV-1 infection.

Inflammatory responses at mucosal surfaces after human immunodeficiency virus type 1 (HIV-1) transmission may influence disease outcome. We evaluated levels of interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha, IL-8, IL-10, and IL-12 in genital tract and plasma specimens from 44 women with acute HIV infection and 29 HIV-negative control women (13 of whom were women in the acute HIV infection cohort who had preinfection samples available for analysis). Women with acute HIV infection had significantly elevated levels of IL-6, IL-10, and IL-12 in genital tract specimens and elevated levels of IL-1beta, IL-8, and IL-10 in plasma specimens, compared with HIV-negative control women. Levels of IL-1beta, IL-6, and IL-8 in cervicovaginal specimens from women with acute HIV infection showed a significant inverse correlation with systemic CD4(+) cell counts, suggesting that mucosal inflammation is associated with low CD4(+) cell counts during acute HIV infection

Preventing HIV Infection in Women: A Global Health Imperative

Women account for approximately one-half of all human immunodeficiency virus (HIV) infections worldwide. Sexual transmission is the dominant mode of HIV transmission to women, and there is a concomitant associated epidemic of transmission to infants. The majority of HIV infections in women are in sub-Saharan Africa, with a disproportionate burden in young women < 25 years of age. Acquisition and prevention of HIV infection in women is complex and influenced by biological, behavioral, and structural factors. Efforts to reduce the incidence of HIV infection among women in sub-Saharan African could play a substantial role in altering global trajectories of HIV infection. Increasing access to sexual and reproductive health services, addressing gender-based violence and social instability, reducing poverty and the need to engage in sex for survival, and encouraging greater male responsibility are critical short-to-medium-term interventions. Efforts to find a microbicide and HIV vaccine need to be matched with efforts to deepen understanding of acquisition of HIV in the female genital tract to inform development of targeted molecules for prevention of HIV infection

Epidemiological Impact of Tenofovir Gel on the HIV Epidemic in South Africa

BACKGROUND: Tenofovir gel, an antiretroviral-based vaginal microbicide, reduced HIV acquisition by 39% in women in a recent randomized controlled clinical trial in South Africa. METHODS: To inform policy, we used a dynamical model of HIV transmission, calibrated to the epidemic in South Africa, to determine the population-level impact of this microbicide on HIV incidence, prevalence, and deaths and to evaluate its cost-effectiveness. RESULTS: If women use tenofovir gel in 80% or more of sexual encounters (high coverage), it could avert 2.33 (0.12 to 4.63) million new infections and save 1.30 (0.07 to 2.42) million lives and if used in 25% of sexual encounters (low coverage), it could avert 0.50 (0.04 to 0.77) million new infections and save 0.29 (0.02 to 0.44) million deaths, over the next 20 years. At US $0.50 per application, the cost per infection averted at low coverage is US$2392 (US $562 to US$4222) and the cost per disability-adjusted life year saved is US $104 (US$27 to US $181); at high coverage the costs are about 30% less. CONCLUSIONS: Over 20 years, the use of tenofovir gel in South Africa could avert up to 2 million new infections and 1 million AIDS deaths. Even with low rates of gel use, it is highly cost-effective and compares favorably with other control methods. This female-controlled prevention method could have a significant impact on the epidemic of HIV in South Africa. Programs should aim to achieve gel use in more than 25% of sexual encounters to significantly alter the course of the epidemic

Design challenges facing clinical trials of the effectiveness of new HIV prevention technologies

Recent successes of antiretroviral pre-exposure prophylaxis (PrEP) in preventing HIV infection have raised questions whether further placebo controlled trials of new HIV-prevention technologies are ethically justifiable. A trial with active agent(s) in the comparator group can be designed either as a superiority or non-inferiority trial. In a non-inferiority trial the hypothesis tested is that the intervention is not inferior to, by a predefined clinically relevant amount, or at least as effective as, the comparator. Non-inferiority trials pose challenges in data interpretation.Firstly it is possible to show equivalence of two non-effective interventions. If the active comparator intervention is ineffective, the new intervention would be shown to be non-inferior to this inactive intervention, while neither intervention is superior to placebo or no intervention. The second challenge is that any effect that dilutes the true efficacy of an intervention in a trial, such as non-adherence, loss to follow-up or protocol violations, makes it easier for the two interventions to be declared equivalent. Non-differential low adherence is unlikely to lead to the conclusion that an inferior intervention is non-inferior. However, differential adherence between study arms, which is more likely in non-blinded trials, is likely to bias the results and lead to incorrect conclusions. Investigators conducting non-inferiority trials will have to pay special attention to supporting, measuring and maintaining high adherence. The goal in future non-inferiority trials should be to maintain similar levels of high adherence in all study arms, but at a minimum to reduce the likelihood of differential adherence across study arms

Circular migration and sexual networking in rural KwaZulu/Natal: implications for the spread of HIV and other sexually transmitted diseases

Patterns of migration do not simply arise out of chance. In South Africa, for example, migration patterns are a result of decades of legislation aimed at restricting the movements of the majority of the population and providing a steady flow of cheap black labour to the gold mines and other industries. In the new democratic South Africa, restrictive laws have been lifted, but circular migration remains a way of life for several million black South Africans. This paper examines the social and epidemiological implications of widespread circular migration from the perspective of a rural South African Health District. In particular, we report our findings on the patterns and prevalence of migration into and out of the Hlabisa Health District in rural KwaZulu/Natal, and the patterns of sexual networking of migrants and their rural partners. We conclude by examining the implications of these patterns of migration and sexual networking for the spread of HIV and other STDs

Under-reporting in hepatitis B notifications

Notification and laboratory data for the period January 1985 December 1988 were compared in order to estimate: (i) the minimum level of under-reporting of hepatitis B; and (ii) the consistency of the level of under-reporting, both regiorially and nationally. Ratios between hepatitis B notifications and positive hepatitis B laboratory tests (reporting ratios) were calculated to quantify the discrepancy between these parameters. There were at least 7 positive hepatitis B laboratory results for each notified case of hepatitis B during each year studied. The differences between the national reporting ratios for each of the study years were small, indicating that nationally the level of reporting of hepatitis B is fairly consistent. The Cape region had the highest and most constant level of hepatitis B reporting compared with other regions. We conclude that the national incidence of hepatitis B is at least 7 times higher than that calculated from notification data. Further, the inter-year analysis of hepatitis B notification data to identify trends nationally and within the Cape region is valid. However, caution is called for when comparing the incidence rates between regions due to inter-region and region-specific inter-year inconsistencies in reporting levels