Heterosexual HIV diagnoses decline as a proportion of total infections despite falling circumcision prevalence

When the extremist Circumcision Foundation of Australia launched its current push for boosting infant circumcision to combat HIV in a Medical Journal of Australia editorial in 2010, the argument depended entirely on the claim that heterosexual diagnoses were increasing as a proportion of total infections. They wrote:

Regular surveillance indicates that HIV in Australia is slowly following the trend in Western Europe and North America toward an increased proportion of transmission occurring through heterosexual contact. Although the epidemic in Australia is likely to remain concentrated for some time among men who have sex with men, the proportion of new diagnoses attributable to heterosexual contact has risen... . This raises the question of whether low-prevalence countries such as Australia — with an increasing proportion of HIV cases attributed to heterosexual contact — should consider increasing the rate of infant male circumcision to reduce future HIV infections. [emphasis added]

This argument was not seriously challenged at the time, partly because one of the authors, David Cooper, is director of the Kirby Institute, which is responsible for monitoring HIV in Australia, and therefore a recognised authority on the matter. The claim was repeated most recently by Adrian Mindel, the CFA’s sexual health “expert”, in a Radio National circumcision debate on 15 September this year. The Kirby Institute has now released its 2011 HIV Surveillance report showing that as a proportion of total infections heterosexual transmission actually fell 17 per cent last year!

So where does that leave the CFA’s argument? Pretty much in the same place as before, since it was bogus to begin with. It is meaningless to talk about the proportion of heterosexual infections, since changes in this measure are most likely the result of incidence changes in the other, much larger category of infection, male homosexual contact. In particular, it implies nothing at all about female-to-male sexual transmission of HIV, the only route of any possible relevance to circumcision. Detailed examination of the data shows that to the extent heterosexual transmission has risen in the past decade it is driven by two factors: a near doubling in the number of infected women “from a high prevalence country” and a rise in the number of cases among males over 40, who have the highest levels of circumcision. Among heterosexual men under 30 the rates of HIV infection are virtually unchanged, despite a dramatic fall in the prevalence of circumcision in this age group.

When the 2011 surveillance report was released in October 2012 media coverage focused on the finding that the overall HIV prevalence had increased by 8% compared with 2010. They totally ignored the finding that the proportion of heterosexual infections had declined by double that amount. All the media were doing was repeating the information in the Kirby media release, which noted that “HIV continued to be transmitted primarily through sexual contact between men”, but failed to go into details. It is to the credit of Associate Professor David Wilson, the Kirby spokesman quoted in the media release, that he did not mention circumcision in his comments and observed that “some of the rise in reported HIV diagnoses could be attributed to changes in testing trends among men who have sex with men who are the most affected population group.” He added that “earlier diagnosis among these people and initiation of antiretroviral therapy would have large health benefits for the individual and reduce new infections in the community.” No mention of cutting babies here. Many studies have established that circumcision does not reduce the risk of HIV infection among homosexual men and injecting drug users.

It is a sad indictment of the CFA, and Professor Cooper (who ought to know better) in particular, that they could engage in such cynical misrepresentation of the data about such a serious issue as HIV in order to prosecute their wrong-headed drive to resurrect infant circumcision.

The 2012 Annual Surveillance Report of HIV, viral hepatitis, STIs can be downloaded from the Kirby Institute website.