HIV Prevalence in Eastern Zimbabwe Decreases to 20.5%, Reduction in Prevalence Among Young People, Study Says
The HIV prevalence rate in the eastern Zimbabwean province of Manicaland declined from 23% in 1998 to 20.5% in 2003, associated with a "stee[p]" drop in prevalence among young people, according to a study published in the Feb. 3 edition of the journal Science, London's Guardian reports. Simon Gregson, one of the study's authors and a senior lecturer for the Division of Epidemiology, Public Health and Primary Care at Imperial College London, and colleagues administered HIV blood tests and gave questionnaires about sexual activity to 9,454 people living in 12 communities in Manicaland. Researchers collected blood samples and administered a sexual behavior questionnaire from 1998 through 2000, and they then repeated the process in 2003 (Sample, Guardian, 2/3). The researchers found that HIV prevalence among women and girls ages 15 to 24 decreased from 16% to about 8%, an approximately 50% decline, VOA News reports. Prevalence among men and boys ages 17 to 19 also fell about 23%, according to the study (Berman, VOA News, 2/2). Researchers also found HIV prevalence in men ages 17 to 54 decreased from 19.5% to 18.2%, while prevalence in women ages 15 to 44 decreased from 25.9% to 22.3% (Agence France-Presse, 2/2).
Potential Reasons for Prevalence Decline
"A key reason for this decline appears to be the reduction in the number of casual sexual relationships, although there was also a delay in the onset of sexual activity and increases in condom use prior to the time of the study [and that] may also have contributed," Geoffrey Garnett, a professor at ICL and co-author of the study, said (Fox, Reuters, 2/2). The percentage of men and women who said they recently had a "causal sexual partner" fell by 49% and 22%, respectively, according to the Guardian. In addition, the study indicates a drop in the number of young people who said they are sexually active -- a decline from 45% to 27% for 17- to 19-year-old men and boys and 21% to 9% for 15- to 17-year-old girls. The researchers did not find any evidence of change in consistent condom use (Guardian, 2/3). "Although we can't say for certain, fear of HIV and AIDS may have influenced this change in behavior, with Zimbabwe's well-educated population, good communications and health service infrastructure all combining to create this effect," Gregson said (Reuters, 2/2).
The "whole thing has become very real to people," Gregson said, adding, "[P]eople realize that [contracting HIV] is not something which only happens to those involved in prostitution or people who are very promiscuous. It is something that can happen to everybody" (VOA News, 2/2). Deputy U.S. Global AIDS Coordinator Mark Dybul said, "Perhaps one of the most interesting things is that the greatest behavior change was in abstinence and fidelity," adding, "The relative change in condom use was not as remarkable" (Check, Nature.com, 2/2). UNAIDS previously had recorded a decline in HIV prevalence in Zimbabwe, crediting the decline to condom use in the country, which is estimated at more than 80%, and changes in sexual behavior (Reuters, 2/2). In a related Science perspective, Richard Hayes and Helen Weiss of the MRC Tropical Epidemiology Group of the London School of Hygiene and Tropical Medicine write that "the significant decline in HIV prevalence in Zimbabwe ... provides clear evidence of a reduction in HIV prevalence associated with behavior change in this region of Africa" (Agence France Presse, 2/2).
"The World" -- a co-production of BBC World Service, PRI and WGBH Boston -- on Thursday reported on the study. The segment includes comments from Gregson; Jodi Jacobson -- executive director of the U.S.-based Center for Health and Gender Equity; and Maria Waver, a researcher at Columbia University who conducted a clinical trial with 3,000 HIV-negative men in Uganda on the timing of circumcision and HIV prevalence (Costello, "The World," PRI, 2/2). The complete segment is available online in Windows Media.