Recent studies help solidify HIV/STD link
March 1, 1998 3 minutes read
Recent studies help solidify HIV/STD link
Treating STDs alone can reduce HIV
Driving the linkage between STD and HIV prevention is a growing body of data that has shown in various settings how STDs facilitate HIV transmission and how treating STDs can decrease the spread of HIV.
One of the earliest landmark studies documented the impact of improved STD treatment in rural Tanzania. This randomized controlled trial, reported in Lancet in 1995, suggested that such treatment could reduce the incidence of HIV in areas with high STD rates by as much as 40%.1
Study: 252 HIV infections prevented
In a follow-up report on the study in Lancet in December, the London School of Hygiene and Tropical Medicine calculated that over a two-year period during which 11,632 STD cases were treated, the incidence of HIV was 1.16 for the treated group, compared to 1.86 for the control group. The researchers estimated that STD treatment had prevented 252 HIV infections, and that the cost per disability-adjusted life-year was only $10.33.2Other recent studies have shown the impact of STD treatment on HIV infection. Last year, researchers found that HIV-positive patients treated with antibiotics for gonorrhea and other sexually transmitted diseases have lower levels of HIV in their semen, resulting in reduced risk for transmitting the virus.
At the STD clinic in Malawi’s capital city of Lilongwe, a mixed team, primarily of University of North Carolina and Malawi specialists, recruited 86 young male patients infected with HIV-1. Two-thirds of them also had gonorrhea; the rest, chlamydia and trichomonas STD. Another 40 HIV-positive men and 127 HIV- negatives served as controls.
The volunteers donated samples of their semen. Then, all the STD-positive men, identified by their urethritis, received a course of the antibiotic gentamicin, which cleared up their venereal diseases in two weeks. Pre- and post-antibiotic semen specimens revealed that HIV-positive men with concomitant STD urethritis had concentrations of viral RNA in their semen that were eight times higher than viral RNA concentrations in the semen of HIV-positives without venereal urethritis. Yet, both virus-infected cohorts had similar CD4 counts and concentrations of viral RNA in their blood plasma.
T. vaginalis correlated with HIV
In another study, published as a letter in the January 1998 issue of Lancet, researchers at the HIV Epidemiology Program at the Los Angeles County Department of Health Services suggest that Trichomonas vaginalis may amplify HIV-1 transmission in industrialized countries. Their study was based on their findings that HIV-positive women at a Los Angeles clinic had high rates of trichomonas, the most common STD in women.T. vaginalis appears to activate a strong local immune response that increases the infiltration of leukocytes, even in symptom-free patients. Moreover, as many as half of infected women have lesions in the genital area, which could increase risk of HIV infection.
"Even if trichomonas amplifies HIV-1 transmission by a small degree, the amount of HIV-1 transmission attributable to this agent and its impact on epidemic spread may be substantial because the infection is common," the authors noted.
Earlier studies showed that other STDs facilitate HIV transmission at least two- to fivefold.3
References
1. Grosskurth H, Mosha F, Todd J, et al. Impact of improving treatment of sexually transmitted diseases on HIV infection in rural Tanzania: randomized controlled trial. Lancet 1995; 346:530-6.
2. Gilson L, Mkanje R, Grosskurth H, et al. Cost- effectiveness of improved treatment services for sexually transmitted diseases in preventing HIV-1 infection in Mwanza region, Tanzania. Lancet 1997; 350:1,805-1,809.
3. Wasserheit J. Epidemiologic synergy: interrelationships between human immunodeficiency virus infection and other sexually transmitted diseases. Sex Transm Dis 1992; 9:61-77.
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