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Preventing HIV-1: lessons from Mwanza and Rakai

1999; Volume: 353; Issue: 9163 Linguagem: Inglês

10.1016/s0140-6736(99)00078-1

0099-5355

Angus Nicoll, Margaret Johnson, Michael Adler, Marie Laga,

Reproductive tract infections research

Observational studies early in the HIV-1 epidemic showed the strong relation between sexually transmitted disease (STDs) and HIV-1 infection.1Laga M Diallo MO Buvé A Inter-relationship of sexually transmitted diseases and HIV: where are we now?.AIDS. 1994; 8: S119-S124Google Scholar By causing inflammation, ulceration, or both, in the genital tract, STDs increase the shedding of HIV-1 in men and women and may also increase susceptibility to HIV-1 infection. The community randomised trial in Mwanza, Tanzania, showed that improved syndromic management of STDs in primary health care reduced the rate of HIV-1 infection by about 40% in rural communities.2Grosskurth H Mosha F Todd J et al.Impact of improved treatment of sexually transmitted diseases on HIV infection in Tanzania: a randomised controlled trial.Lancet. 1995; 346: 530-536PubMed Scopus (1190) Google Scholar This intervention showed only a slight impact on the overall prevalence of most treatable STDs, many of which were symptomless, but a striking impact on the prevalence of symptomatic urethritis in men and of new cases of active syphilis.3Mayaud P Mosha F Todd J et al.Improved treatment services significantly reduce the prevalence of sexually transmitted disease in rural Tanzania: results of a randomised controlled trial.AIDS. 1997; 11: 1873-1880Crossref PubMed Scopus (102) Google Scholar The investigators concluded that the impact of the intervention on HIV-1, transmission was due to a reduction in the duration of symptomatic STDs, which are more likely than symptomless infections to increase the shedding of and susceptibility to HIV-1. Maria Wawer and colleagues (Feb 13, p 525)4Wawer MJ Sewankambo NK Serwadda D et al.Control of sexually transmitted diseases for AIDS prevention in Uganda: a randomised community trial.Lancet. 1999; 353: 525-535Summary Full Text Full Text PDF PubMed Scopus (641) Google Scholar measure the effect of STD control by periodic mass treatment for bacterial and protozoal STDs on HIV-1 infection in Rakai District, Uganda. Between rounds of mass treatment, little or no effective treatment for STDs seems to have been available to these communities. There was no difference in incidence of HIV-1 between the intervention and comparison communities after 20 months. Penny Hitchcock and Lieve Fransen, in their accompanying commentary,5Hitchcock P Fransen L Preventing HIV infection: lessons from Mwanza and Rakai.Lancet. 1999; 353: 513-515Summary Full Text Full Text PDF PubMed Scopus (52) Google Scholar attribute the results obtained in the two studies to the different stages and dynamics of the HIV-1 epidemic in the two areas. We propose another explanation. Periodic mass treatment of the general population is not an effective strategy for STD control. The communities studied in Rakai had year-round road access. People living there probably travel frequently, and may have sexual encounters outside their communities, leading to continuous reintroduction of STDs between treatment rounds. In support of our hypothesis, after 20 months of follow-up the intervention group only showed a significant reduction in trichomoniasis and serological evidence of syphilis, and no difference was seen for all the other STDs targeted. The treatment given to most adults (single-dose azithromycin, ciprofloxicin and metronidazole), should be highly efficacious against most bacterial STDs and reduce the prevalence of gonorrhoea and genital chlamydia to almost zero. Yet in the intervention group, only slight reductions in prevalence of STDs were achieved after two rounds of mass treatment. Mass treatment once every 10 months did not stop STD transmission. Moreover, coverage of mass treatment was incomplete: 80% of eligible residents received the treatment at each round, but fewer than 70% of enumerated residents were covered. Mass treatment of communities as a public-health strategy for STD is difficult in terms of logistics, sustainability, cost, emergence of resistance among other pathogens, and may also undermine existing health-care and prevention structures. Prevention is of the utmost importance in the developing world. Provision of effective treatment for symptomatic STDs has been shown to prevent HIV-1 infection. The results of the Rakai study, which assessed a different intervention, must not be used as an excuse to cut back on the resources made available for STD control. Preventing HIV-1: lessons from Mwanza and RakaiAuthors' reply Full-Text PDF