Sine qua non


Sorry, I couldn't resist

Cecilia Dugger’s recent article in the NYtimes highlights South Africa’s faltering efforts to fight HIV/AIDS through large-scale male circumcision. It’s a decent read, although Dugger’s angle is tangent to that of the current medical consensus: mass circumcision is an extremely cost-effective preventative intervention and should be pursued with zeal.

A quick primer for the unfamiliar: in 2005 a randomized trial in Uganda revealed compelling evidence that circumcision reduces a man’s chance of contracting aids by roughly 50%. A round of follow-up trials confirmed that, at least within the span of the trial, that circumcised men were better-protected. The WHO declared the intervention a worthwhile one, and with the past few years we’ve seen unprecedented levels of mass circumcision around the continent.

This is mostly fine and well – the intervention has been proved to be effective in the short term – I’ve always had a few concerns though (I’ll warn you that, as usual, I’m out of my depth here – this is why we need a health blogger!):

A recent study in the Lancet reported what many have suspected: male circumcision does absolutely nothing to prevent male-to-female transmission of HIV. Thus, while circumcision will obviously protect women indirectly by reducing the chances their spouse will contract HIV (at least, in the limited time span of the randomized trial), it will do nothing for them if their spouse ends up contracting the virus, or already has it.

This essentially means that the first line of defense against HIV remains the condom. Health of workers understand this, and so continue to push condom use alongside the circumcision. However I’ve seen little effort to estimate the long run behavioral effects of the intervention. The original Ugandan study determine that the intervention didn’t substantially chance behavior, but this was back when the intervention wasn’t known to be effective. Now since circumcision is known to be partially effective, many men may now decide to trade off some of that protection for extra pleasure. A good measure of the elasticity of promiscuity would go a long way (I never thought I’d ever write elasticity and promiscuity in the same sentence).

There are some troubling anecdotal signs that men may be using the circumcision as their only means of protection. This quote from Dugger’s article stands out:

Even without government involvement, demand for the surgery, performed free under local anesthetic, has surged over the last year here at the Orange Farm clinic.

When was the last time you read a story about excess demand for condoms in the South African press? These men are clearly not all going to go on using condoms – it’s actually quite likely that circumcision is acting as a substitute for condom use – men would rather take the snip and accept a little risk.

This isn’t necessarily the case, but we’ll never really know unless we start observing behavior in the long run (most of the medical trials are abandoned prematurely due to ethical reasons – when the intervention clearly works the health workers are compelled to offer the control t treatment). We need to be sure that (i) we aren’t creating perverse incentives and (ii) we aren’t crowding out condom use.

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