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Zambia: Another study fails to find that foreskins increase risk of HIV…

… but still recommends circumcision

A study of the possible link between genital herpes and increased risk of HIV in Zambia did find that men with herpes were more likely to be HIV-positive, but also found that lack of circumcision did not increase the risk of HIV infection. Quite the contrary, the study found that uncircumcised men were less likely to contract HIV. In their discussion of the results, however, the authors of the study failed to mention this vital fact, and concluded by recommending that circumcision be promoted as an AIDS control strategy – thus violating the most basic principles of evidence-based medicine.

The Zambian study was conducted by researchers from the United States Centers for Disease Control – well known for its pro-circumcision agenda. They recruited 1062 male farm workers at a sugar estate in Zambia to participate in an experiment known as a prospective cohort study. The researchers were looking for a link between genital herpes (herpes simplex type-2 or HSV-2) infections and developing an infection with HIV-1. The study had two outcomes of interest.

First, they looked at factors that affect the prevalence of HIV-1 infection (whether the men were infected at the time of recruitment). Second, they measured the incidence of HIV-1 infection (new infections detected during the follow-up period). At the time of recruitment 20.7% of the men were HIV-positive. Men with a positive blood test for past herpes were five times more likely to be HIV-positive at the time recruitment. Other factors significantly associated with being HIV-positive were self-reported genital ulcers in the past year and being widowers. Rates of HIV-1 infection at the time of recruitment were the same in circumcised men and uncircumcised men (20.71% versus 20.76%). When adjusted for other factors, there was no significant association between circumcision status and HIV-1 prevalence.

The second half of the study involved following 731 participants who started off as HIV-negative and who made at least one follow-up visit. Becoming HIV-positive during the follow-up period was independently associated with a positive blood test for herpes at the beginning of the study, and 18 times more likely in men who developed a first-time HSV-2 (herpes) infection during the follow-up period. During the follow-up period uncircumcised men developed 23 infections in 5686 months of patient follow-up (4.04 per 1000 months), while circumcised men developed four infections in 817 months of follow-up (4.89 per 1000 months). This means that uncircumcised men had a slightly lower (but probably not statistically significant) risk of HIV infection. When adjusted for other factors, circumcision status made no difference to the risk of infection with HIV.

A significant weakness of the study is its reliance on self-reported circumcision status – something about which men are surprisingly uncertain. While the investigators assumed that all the HIV infections were transmitted sexually, it is also possible (even likely) that men with genital herpes would seek medical care, and in doing so placed themselves at greater risk of HIV infection through non-sterile medical treatment (iatrogenic infection) – notoriously common in the over-stretched health services of underdeveloped countries.

This is yet another study that fails to confirm the “60% reduction in risk of HIV infection” claimed for circumcision in the three famous randomized clinical trials. Such a reduction is outside the 95% confidence intervals of this and several other studies, indicating serious doubts about the clinical trials. Despite this, the researchers in the Zambia study recommend that company health centres should “promote and provide medical male circumcisions” as a part of the effort to decrease infection rates: yet their own data that shows that circumcision would either have no impact, or might even increase the risk of HIV infection. It would appear that the authors, even in light of their own negative findings, are unwilling to stray from the CDC’s pro-circumcision agenda, and thus fail to observe the basic principles of evidence-based medicine: that recommendations for treatment must follow logically and directly from the evidence. According to the data in this study, to recommend circumcision as a preventive strategy in Zambia is ideological and plainly anti-scientific.

Originally published on: http://www.circinfo.org/

The article is: Heffron R, Chao A, Mwinga A, Sylvester Sinyangwe S, Sinyama A, Ginwalla R, Shields M, Kafwembe M Kaetano L, Mulenga C, Kasongo W, Mukonka V, Bulterys M. High prevalent and incident HIV-1 and herpes simplex virus 2 infection among male migrant and non-migrant sugar farm workers in Zambia. Sex Transm Infect 2011; 87: 283-8.