David Gisselquist

HIV infections in sub-Saharan Africa not explained by sexual or vertical transmission

An expanding body of evidence challenges the conventional hypothesis that sexual transmission is responsible for more than 90% of adult HIV infections in Africa. Differences in epidemic trajectories across Africa do not correspond to differences in sexual behaviour. Studies among African couples find low rates of heterosexual transmission, as in developed countries. Many studies report HIV infections in African adults with no sexual exposure to HIV and in children with HIV-negative mothers. Unexplained high rates of HIV incidence have been observed in African women during antenatal and postpartum periods. Many studies show 20%–40% of HIV infections in African adults associated with injections (though direction of causation is unknown). These and other findings that challenge the conventional hypothesis point to the possibility that HIV transmission through unsafe medical care may be an important factor in Africas HIV epidemic. More research is warranted to clarify risks for HIV transmission through health care.

Let it be sexual: how health care transmission of AIDS in Africa was ignored

The consensus among influential AIDS experts that heterosexual transmission accounts for 90% of HIV infections in African adults emerged no later than 1988. We examine evidence available through 1988, including risk measures associating HIV with sexual behaviour, health care, and socioeconomic variables, HIV in children, and risks for HIV in prostitutes and STD patients. Evidence permits the interpretation that health care exposures caused more HIV than sexual transmission. In general population studies, crude risk measures associate more than half of HIV infections in adults with health care exposures. Early studies did not resolve questions about direction of causation (between injections and HIV) and confound (between injections and STD). Preconceptions about African sexuality and a desire to maintain public trust in health care may have encouraged discounting of evidence. We urge renewed, evidence-based, investigations into the proportion of African HIV from non-sexual exposures.

Mounting anomalies in the epidemiology of HIV in Africa: cry the beloved paradigm

In North America Europe and many parts of Asia the ignition of regional epidemics and rapid HIV transmission has been associated principally with the sharing of contaminated injecting equipment and with anal intercourse. Though heterosexual intercourse has been virtually the sole explanation offered for the AIDS epidemic in sub-Saharan Africa to our knowledge in no other part of the world has penile-vaginal exposure (as opposed to “heterosexual sex”) been demonstrated to initiate or sustain rapid HIV propagation. HIV is not transmitted by “sex” but only by specific risky practices. It is not transmitted by “injections” but only by contaminated implements which need to be clearly differentiated as to type and frequency of injection and by the conditions of the exposure setting. In virtually all societies affected by HIV to date both routes seem to play important roles. If we are to understand and intervene in each of these epidemics well-designed studies at both the population and individual levels are urgently needed. It is vital that these be properly controlled for parenteral exposure specific sexual practices and other co-factors and the complex and specific social patterns and networks that accompany them. (excerpt)

Heterosexual transmission of HIV in Africa: an empiric estimate.

For more than a decade, most experts have assumed that more than 90% of HIV in African adults results from heterosexual transmission. In this exercise, we show how data from studies of risk factors for HIV can be used to estimate the proportion from sexual transmission, and we present our estimates. Calculating two ways from available data, our two point estimates — we do not estimate confidence intervals — are that 25-29% of HIV incidence in African women and 30-35% in men is attributable to sexual transmission; these estimates assume 10% annual epidemic growth. These findings call for reconceptualization of research to more accurately assess routes of HIV transmission.

Four policies to reduce HIV transmission through unsterile health care.

Residents of many developing countries face risks for themselves and their families to contract HIV and other bloodborne pathogens during unsterile health care. Helping people to understand and reduce these risks enlists their assistance to control the HIV/AIDS epidemic. To reduce HIV transmission through health care, we recommend four policies that international, foreign, and local public and private organizations can adopt and begin to implement even with little or no additional funds: (1) Educate the public about risks to contract HIV through unsterile health care. (2) Promote transparent practices for injections and other procedures that allow patients to see and know that care is safe (e.g., taking a new auto-disable syringe out of a sealed package and taking injecta from a single-dose vial). (3) Promote safe health care practices equally for clients and staff. (4) Establish a zero-tolerance policy for iatrogenic HIV infections, with publicly reported monitoring and investigations.

Running on empty: sexual co-factors are insufficient to fuel Africa's turbocharged HIV epidemic

The hypothesis that heterosexual transmission drives sub-Saharan Africas HIV epidemics requires much faster transmission dynamics in Africa than in the US and Europe, where heterosexual transmission is arguably insufficient to maintain existing levels of HIV prevalence. Initially, experts surmised that Africans had more sexual partners; however, studies of sexual behaviour circa 1990 undermined this assumption. Next, it was supposed that the high burden of bacterial sexually transmitted disease (STD) in Africa explained greater HIV transmission efficiency; however, during the 1990s, community studies in Africa showed that STD had much less than expected impact on HIV transmission. Current attempts to explain HIV as a primarily sexual epidemic in Africa propose multiple factors, including herpes simplex virus type 2, lack of male circumcision, concurrency, and others. These factors also fail for various reasons to account for Africas HIV epidemics: they are present also in the US and/or Europe; they do not correlate with differences in HIV prevalence across Africa; etc. While behavioural and biological variables influence personal risk for HIV acquisition, the available evidence suggests that they do not differentiate African from US and European epidemics, nor do they determine the differential HIV epidemic trajectories noted across Africa.

Non-sexual transmission of HIV has been overlooked in developing countries

EDITOR—Accumulating evidence undermines the belief that heterosexual transmission in developing countries has as large—and that unsterile medical equipment has as little—a role as supposed by many HIV experts. In 1983 the World Health Organization identified contaminated sharps—but not heterosexual promiscuity—as a risk factor for HIV in tropical countries.1 During the next five years, however, high rates of HIV infection were reported in female sex workers and patients at clinics for sexually transmitted diseases. By the late 1980s a consensus had …

Review of evidence from risk factor analyses associating HIV infection in African adults with medical injections and multiple sexual partners.

Studies of risk factors for human immunodeficiency virus (HIV) infections in sub-Saharan Africa present a wealth of evidence relevant to ongoing debates about the contributions of unsterile health care and sexual transmission to Africas HIV epidemics. From studies which meet search criteria (n = 39) we calculate population attributable fractions (PAFs) for incident and prevalent HIV infections associated with exposure to medical injections and with having more than one sexual partner. Median and mean crude PAFs for injections for both incident and prevalent HIV exceed those for multiple partners. Evidence suggests that adjustments for reverse causation (people with HIV-related symptoms seeking injections) and confounding do not explain away the large PAFs for injections. Misreporting of sexual behaviour has an unknown impact on PAFs for multiple partners. However, most PAFs for incident HIV infections are from communities with low-growth epidemics; hence data about the most important risk factors fuelling high-growth epidemics are sparse. Empirical resolution of ongoing debates may be possible with the aid of future research—especially in high-growth epidemic settings—that investigates risks for HIV transmission through a full range of sexual and parenteral exposures with attention to reverse causation, confound, and quality of sexual behaviour data.

Confound it: latent lessons from the Mwanza trial of STD treatment to reduce HIV transmission

In 1995, an international team reported that improved syndromic management of sexually transmitted disease (STD) in Mwanza, Tanzania, had reduced HIV incidence by 38% in intervention compared to control communities. However, the team has not addressed confound: project interventions might have reduced HIV transmission during health care through provision of syringes and benzathine (replacing short acting) penicillin and through interactions with a coeval safe injection initiative. Mwanzas success in lowering HIV incidence is a puzzle, since it was achieved with only minor reductions in observed STD prevalence. Despite incomplete analyses, reports from Mwanza have encouraged expansion of STD treatment. However, should success be attributed to injection safety rather than to decreased STD prevalence — an hypothesis that fits published data — expanded STD treatment without attention to injection safety could, ironically, increase rather than decrease HIV incidence. To control for confound, additional data and analyses from the Mwanza study are warranted.

Evidence of iatrogenic HIV transmission in children in South Africa.

There is mounting evidence that rapid HIV transmission is fuelled by parenteral exposures in health care settings especially medical injections but also including transfusion of untested blood and others. Not only are injections popular among African patients administered at an estimated 90% of medical visits but also often unnecessary and injection equipment is often reused without sterilisation. Investigation of iatrogenic outbreaks in Russia Romania and Libya has demonstrated both that medical injections are efficient vectors for HIV transmission and that rigorous application of safe injection procedures can virtually eliminate transmission. (excerpt)