But in the heat of all this, very few have stopped and asked themselves the obvious question: Do condoms lower the risk of HIV transmission? Perhaps people think it's too obvious. Encasing the male genitals in a protective barrier during intercourse must necessarily lower the risk of HIV transmission. And so it does, under ordinary circumstances. But that does not mean that it eliminates this risk, and that is an entirely different issue.
Some controversial writers, including prominent Catholic moralists, have argued that the pores in the material which condoms is made of are so large that a considerable number of virus particles will escape the condom. I went through the research on this a while back. Very little is published on it. Those articles that are available suggest that some leakage of virus particles does indeed occur, but that the amount is for all practical purposes negligible. For HIV infection to occur, it is already necessary that a large number of virus particles are transmitted; thus condoms do actually lower the rate of transmission to levels which are, for all intents and purposes, undetectable. One study suggested that they reduced the risk of transmission from 0.1% (for normal intercourse) to 0.00001%. (Carey et al. Effectiveness of latex condoms as a barrier to human immunodeficiency virus-sized particles under conditions of simulated use. Sex Transm Dis. 1992 Jul-Aug;19(4):230-4.) That is, 1 infection in 10 million intercourses. This figure would be higher for people who engage in homosexual practices, as anal intercourse bears a higher risk of transmission than vaginal.
Seepage of virus particles, thus, does not seem to pose a significant concern as to the effectiveness of condoms. There are other, much more pressing, problems which should be addressed and the issue of seepage is an unfortunate distraction from these:
1. Condoms occasionally break or slip off during withdrawal. Studies apparently show that each occurs about 2% of the time (Warner L, Steiner MJ. Male condoms. In: Hatcher RA, Trussell J, Nelson AL, Cates W, Stewart FH, Kowal D, et al. editor(s). Contraceptive Technology. 19th Edition. New York: Ardent Media, Inc., 2007:297–316.)
2. Condoms are most often not used in long-term relationships. For a long while it was presumed by many in the scientific community that HIV in Africa was first and foremost spread through prostitution and casual sexual intercourse. Recently, some scientists have drawn attention to the fact that very few Africans actually engage in such high-risk behaviour. Rather, it is the norm in many African cultures to be essentially polygamous, with both men and women having multiple concurrent long-term partners. This pattern is much more inducive to HIV transmission than either casual sexual encounters or serial monogamy. (Epstein, BMJ 2008;337:a2638)
3. It seems that reliance on condoms may encourage a phenomenon known as risk compensation. Sunbathers who spend more time than usual in the sun after applying sunscreen is an example of this. In other words, condoms make people over-confident and causes them to engage in even more risk-seeking behaviour than they otherwise would have, thus offsetting any positive effect condom use by itself produces.
While I have not been able to find any positive scientific evidence for this last point, it is touted by senior Harvard research scientist Dr. Edward Green as a fitting explanation for the fact that there is actually no scientific evidence that increased use of condoms causes a reduction in HIV transmission rates. Green has given an interview to Catholic News Agency, in which he states that although he is a Liberal and is not ideologically opposed to contraception, he agrees with the Pope's statements as they are supported by science. The interview is quite enlightening. Among other things, Dr. Green, who is the director of Harvard University's AIDS prevention project, draws attention to the fact that Uganda early on produced a dramatic reduction in HIV incidence by developing home-grown programs focusing on promoting faithful monogamy. In 2004, after Western 'advisers' had successfully lobbied for greater access to condoms, the incidence rates rose again.
Dr. Green is also of the impression that many organisations combating HIV espouse a false and somewhat racist ideology according to which behaviour change is impossible, especially as regards Africans, and that the only viable option is risk reduction.
A final point: as Dr. Green notes, "anyone who worked in family planning knew that if you needed to prevent a pregnancy, say the woman will die, you don’t recommend a condom.". The chance per intercourse of becoming pregnant is admittedly somewhat higher than the risk of HIV transmission, but still: scientific evidence suggests that condom use only lowers the chance of pregnancy about 85% (Trussell J. Contraceptive efficacy. In: Hatcher RA, Trussell J, Nelson AL, Cates W, Stewart FH, Kowal D, et al. editor(s). Contraceptive Technology. 19th Edition. New York: Ardent Media, Inc., 2007:747–826.) It is clear from this that condoms are far from being a fool-proof device against pregnancy, so how can one expect it to be so against HIV transmission? One review conducted in 1994 even concludes that the risk of HIV transmission is only lowered 69%! (Weller 1993)
In conclusion: used consistently and properly, condoms may lower the risk of HIV transmission somewhat, but they in no way eliminate that risk. They may even encourage risk-seeking behaviour which offsets these gains. Condoms have shown to effectively lower the risk of HIV transmission in sub-populations which are already engaging in high-risk behaviour (such as prostitutes), but not on a larger population level. Given the grave consequences of HIV infection it really is imperative to eliminate the risk of transmission entirely, and condoms can not effect this. Even in the case of married couples where one is infected and the other not (serodiscordant), it is gravely irresponsible to have sex using condoms as the risks are simply too great. Not only the risk of HIV transmission, but also the chance of producing a pregnancy where the child would risk being infected with HIV upon birth if the mother is HIV positive. The Church's opposition to contraception is of course not based on its inefficiency in combating HIV/AIDS, but on the fact that it distorts human sexuality. Nevertheless, even apart from this, the Church is absolutely justified in promoting abstinence outside marriage (and in the case of serodiscordant couples) and fidelity within marriage as the only viable method currently available to stop the spread of HIV/AIDS - both for individuals and populations.
In other words, to quote Dr. Green: "The Pope is right." As usual.
Some additional reading:
- Hearst N, Chen S. Condom promotion for AIDS prevention in the developing world: is it working? Stud Fam Plann 2004 Mar;35(1):39-47
- Kajubi et al. Increasing condom use without reducing HIV risk: results of a controlled community trial in Uganda. J Acquir Immune Defic Syndr 2005 Sep 1;40(1):77-82