Saturday, July 16, 2011

Guy Scott » An AIDS-free generation?

By Guy Scott

When antiretroviral drugs (ARVs) were first used on a quantity of HIV+ people, an obvious question presented itself to those with some knowledge of the disease: what is the effect of these drugs on the actual transmission of the HIV from one person to another – from a positive person to a hitherto uninfected person with whom he or she has sex? This question has not been discussed much publicly for reasons that are not so hard to understand.

Suppose the answer had been that the chance of an HIV+ person infecting another was not altered for the better by ARVs. The implications would have been an ethical minefield.

By keeping an HIV+ person alive and kicking longer, you would be increasing the spread of HIV – you might even be exacerbating the epidemic since the average treated person might get to have sex with and transmit the disease to more partners over a longer time.

The natural answer to this would have been to withdraw ARVs from use to allow already infected people to die quicker and lower the pressure of the epidemic. But not many people were prepared to say this publicly, and the matter was kept quiet while we waited for more information!

Even if the answer to the big question was that ARVs lowered the likelihood of virus transmission somewhat, there was another ethical conundrum. Should you inform people that their risk of passing HIV on to a negative person had been reduced by virtue of their being on ARVs? The obvious implication might be a tendency towards less care – less condom use for example – resulting from the illusion of safety.

So again it seems that most people shut up and waited....
A large worldwide trial to compare transmission with and without early ARV treatment was set up in 2005 using “discordant” couples in which one person was HIV+ and the other HIV-. The total sample was 1700 and the population was drawn from Latin America, Africa, Asia and the US.

All the HIV+ partners were in the early stages of HIV infection and were symptom. free with CD4 counts around 500. Half of the couples were assigned to the “control” group where they did not receive ARV treatment until they showed clinical symptoms of AIDS or suffered a low CD4 count (itself a symptom of AIDS).

This is the standard procedure in Zambia as elsewhere. In the other half of the sample ARVs were given immediately, despite their apparent robust good health. The point is that during this early “healthy” period, HIV carriers are normally highly infectious. What would the ARVs make of that?

The result of the “HPTN-052” trial was not expected until about 2015 but – amazing to relate – the results are already so conclusive that the trial has been stopped to enable the control group to receive early ARVs. This was the result of yet another ethical consideration.

You see: the untreated control group produced 27 HIV transmissions to the formerly HIV- partner while the treated test group produced precisely one! The figures for TB occurrence – an early indicator for HIV – were 17 and 3 respectively. Even a Zambian politician would have difficulty arguing with those numbers.

The discovery that ARVs virtually kill all transmission of the HIV if given at an early enough stage opens the door to the possibility of an ‘AIDS-free generation’ without depending solely upon an unlikely degree of behavioural change.

The only likely catch – though it is a big one – is that the sexually active segment of the population, which extends from mid teens to well into so-called geriatric age group, will have to be routinely tested for HIV so that early treatment can be initiated. If you doubt my statement about old people and sexual activity take note that there is an HIV epidemic amongst retirees in Florida.

At present, HIV in Zambia is often diagnosed via the special circumstances of either pregnancy or presenting with AIDS-related opportunistic infections. And even where the symptoms are quite pronounced, it can be difficult to persuade the person to have an HIV test.

So what proportion of adults is prepared to show up annually for an HIV test without feeling the slightest bit unwell, even knowing that it might protect sexual partners against infection?
There would seem to be a strong case for compulsory testing, but this is again fraught with ethical problems.

An attempt at compulsory testing would almost certainly result in sick people failing to present themselves – or their children – at clinics where they might be made to submit to testing for HIV. You see again: this public health business is all about commonsense, ethics, human nature and more ethics. I am so glad I am just a lowly politician.