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 emerged that more than 90% of adult HIV infections in sub-Saharan Africa were attributable to heterosexual contact, and only about 2% to contaminated sharps. This consensus was forged in the absence of empirical studies controlling for confounding between sexual and medical exposures, and despite the fact that unsafe injections are common in developing countries.²,³ More important, inquiry into iatrogenic transmission all but disappeared from the HIV research agenda, and routine epidemiological reports from developing countries—not to mention meta-analyses and evaluations of intervention trials—have often been silent about non-sexual transmission.⁴,⁵

The literature indicates that researchers have undervalued data pointing to a significant role for medical transmission. Many studies, particularly from Africa, report unexplained high rates of HIV incidence during antenatal and postpartum periods, implicating nosocomial exposure. They also report that 20-40% of HIV infections can be attributed to injections by univariate population attributable risk calculations; non-trivial rates of HIV in sexually inexperienced adults; and many HIV positive children with HIV negative mothers.^w1-30 In addition, the frequent lack of association between sexual behaviour variables and HIV trends, and the low rate of penovaginal HIV transmission in studies of serodiscordant couples in Africa as elsewhere, suggest a need to reassess the contribution of heterosexual exposure.

Although cofactors such as sexually transmitted diseases and lack of circumcision may boost heterosexual transmission, the levels of such covariates and their known influences on transmission do not seem sufficient to explain Africa's HIV epidemic. In 1999 public and private international health organisations formed the Safe Injection Global Network (SIGN), currently headquartered at WHO, to promote injection safety. Our view, which suggests a pivotal role for contaminated sharps in the global HIV catastrophe, supports the network's efforts to reduce unnecessary and unsterile injections. Adding such interventions to efforts for HIV prevention may bring greater success than has been achieved to date with a narrow focus on condoms and heterosexual transmission.