Tuesday, December 9, 2008

HIV Eradication

HIV eradication means different things to different people. Some have suggested that HIV could be substantially reduced by universal voluntary counselling and testing (VCT) and universal antiretroviral therapy (ART) for those found to be HIV positive. If it were possible to test every sexually active person around once a year in any population in the world, then it may also be possible to put all those found to be positive on ART.

Personally, I think the chances of testing every sexually active person in a country like Kenya, where a sizable proportion of births are not even registered and many people never see a health professional, are slim. Even testing people once has eluded the Kenyan Government's efforts to date and around 80% of people do not know their status.

I have no doubt that, when the people who came up with such a proposal also come up with a plan on how to implement it, the event will be met with the same level of press coverage. But until that time, I'm sure there will be other plans for eradicating HIV. And if you think universal VCT and ART for those found to be HIV positive is crazy, there is a crazier suggestion and it is already being trialled in Kenya.

Many have heard of post-exposure prophylaxis (PEP), something a bit like the morning after pill for HIV. If you think you have been exposed to HIV infection, through sexual assault, needlestick, accidental exposure to infected blood or any other way, you can visit a suitable medical facility and ask for it. That's if you are lucky enough to live in a country with easy access to such facilities, of course. PEP involves a short course of antiretroviral drugs and it can ensure that you do not become infected with HIV.

That's not the crazy suggestion, by the way. The crazy suggestion is called pre-exposure prophylaxis (PrEP). Anyone deemed to be at risk of becoming infected with HIV can be put on antiretrovirals. This should result in them being much less likely to be infected. If they are already HIV positive but don't know their status, PrEP should result in them being less likely to transmit HIV to others.

That's great, but in a generalised epidemic like Kenya's, all sexually active people are at risk of either contracting HIV or transmitting the virus. Of course, commercial sex workers, men who have sex with men and intravenous drug users are much more likely to contract and transmit HIV. These are known as 'vulnerable groups'. But most HIV here is found among the general population. A relatively small percentage of the country's HIV positive people are members of those groups.

For some, the very idea of providing expensive drugs to commercial sex workers instead of providing them with an alternative to sex work could obscene. And there are other, less radical, harm reduction programmes that could be of use to intravenous drug users.

But another group of people who may be offered PrEP if its trials are successful is 'discordant couples'. Only one member of a discordant couple is HIV positive. Often, the HIV negative partner remains HIV negative for many years, even though the couple may have unprotected sex.

HIV is much more likely to be transmitted in the first two or three months after infection and in the last few months or years, after the progression towards AIDS has started. The period in between can be 10 or 11 years and during this time, HIV positive people are less likely to transmit the virus. Of course, this is a long period of time, and HIV positive people may have many sexual experiences. They may also have other sexually transmitted infections, for example, that could make them more likely to transmit HIV.

The potential for PrEP seems obvious, except that we have not always been very good at assessing what the most important factors are in the spread of HIV. Some point the finger at multiple partners, some say poverty is the main problem, genetic differences in Africans or people of African origin have been blamed, tribal practices, commercial sex work and all manner of things have been blamed.

The problem is that all of these could be important factors and all could play a greater or lesser part in different places and at different times. If we are not very clear about exactly how HIV spread in various countries, that is, the history of the virus's spread, we may not be in a position to make predictions about its future.

At present, people are not always good at taking drugs regularly. Sick people, though, are likely to be better at taking drugs than people who are not sick. That's only a guess, but I can see problems with many people remembering or even bothering to take drugs when they are not sick. The drugs may even have side effects or interfere with other drugs they are taking.

Taking drugs for a large part of your life requires certain changes in lifestyle that many may not like to make, if it were even possible for them to make those changes. Drugs can also fail for various reasons. And resistance can develop among people using a drug for a long time, especially if they don't always stick to the recommended regime.

PrEP, if it is ever practicable, will be a very expensive and dangerous shot in the dark if we are not able to predict what the major trends are in each country and, indeed, in each part of each country. But then, some people are unworried by danger when lots of money is involved. Especially if the danger affects other people, far away from home.

And if HIV is eradicated? Well, then we can go on to other transmissible diseases, non transmissible diseases, poverty, malnutrition, food insecurity, fuel insecurity, exploitation, water and sanitation and, well, there are just too many things to list. These, I would suggest, are some of the underlying conditions that allowed HIV to spread in the first place. In Kenya, many of these are getting worse; we are losing sight of them as we allow ourselves to be distracted by grand proposals for the eradication of HIV.

Of course, we could try to deal with some of those other problems first or at the same time as trying to prevent the transmission of HIV. And then, by the time transmission of HIV is reduced as substantially as the mathematical models predict it will be, we may truly have something to celebrate.

(For further discussion of PrEP, see my other blog, pre-exposureprophylaxis.blogspot.com)


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