Tuesday, July 21, 2009

Test Everyone; Treat Everyone?

Is it possible to eradicate a disease while ignoring its determinants?

Last December a new HIV prevention strategy was proposed (I covered it in this blog in December). It involved testing every sexually active person in a population for HIV (or as many people as possible) and treating anyone found to be HIV positive. The idea is that people on antiretroviral therapy (ART) have a low viral load, so they are unlikely to transmit HIV to others. A mathematical model of this strategy, using data from South Africa, indicates that it could be possible to almost eradicate HIV by 2050.

It has been widely recognised that it is better for HIV positive people to be diagnosed and put on treatment at an early stage in the progression from HIV to AIDS. This proposed strategy could have a lot of benefits for HIV positive people and their partners. As one of the authors of the proposal points out, "treatment is also about prevention". Preventing new infections should be made a much higher priority than it is now and this strategy should also enhance existing prevention efforts.

On the surface the strategy sounds great. The more people who know their status, the better. The more people on ART as early as possible, the better. The fewer people exposed to a high risk of HIV infection, the better. The modelling that the strategy is based on even gives some estimates as to what the costs may be. And the costs of aiming to eradicate the virus are certainly lower than continuing with current measures, where millions of people are becoming infected every year.

But countries with high HIV prevalence have been aiming for years to get as many people as possible to test, as often as they need to. In Kenya, only about 20% of people know their status. Some countries have been more successful in persuading people to test, others have been less successful. And only about one third of people requiring ART, people who would die without it, are already receiving treatment in Kenya.

What measures could persuade a large percentage of people to test, say 80%? And they would need to test regularly, say once a year. The costs involved in implementing both prevention and treatment and care programmes in Kenya and other countries are high. Pledges from donor countries have never been high enough to meet the costs; often, even the sums pledged never materialize.

But perhaps, in a rare fit of generosity, donors would make enough money available to implement a programme that would need to last many years, perhaps even three or four decades. At present, several countries are finding it difficult to keep existing patients on ART, let alone provide treatment for the many who will probably experience serious illness and possibly even die without ever receiving any treatment.

But maybe the two arms of the programme could work, universal testing and universal treatment for everyone infected; or perhaps a high level of testing and treatment could be feasible. I would be very happy to see these goals being achieved. My only worry is that we may forget the sort of conditions that drive epidemics like HIV in the first place:

  • Serious levels of poor health and poor health services, including sexual health, reproductive health, etc

  • Widespread discrimination against vulnerable groups, such as men who have sex with men and commercial sex workers

  • Low levels of school attendance and low educational standards, including sex and sexuality education

  • Few and low quality social services, especially for vulnerable and needy people

  • Crumbling basic infrastructure, especially water and sanitation

  • High levels of corruption at most levels of society and poor governance

  • Low levels of employment and poor labour laws for those in employment

  • Low levels of nutrition and food security

  • High levels of economic inequality, inequality relating to inheritance, etc

  • High levels of gender inequality whereby females and the people they care for are particularly disadvantaged

This is not an exhaustive list and it may seem obvious that we shouldn't forget these things. But HIV is just one disease of many. And there is little point in preventing one disease in people when there are so many other things that cause so much injury or death. But more perversely, failing to deal with some of the structural problems listed above, such as health, education, inequality, discrimination or whatever, can result in failure to halt the transmission of HIV.

Even if everyone dutifully trots to the voluntary counselling and testing clinic every year and everyone found to be HIV positive receives ART, the problems listed above won't just go away. And as long as they continue to be ignored by the international community, as they have been ignored for many years, HIV will not be so easy to eradicate. It is not a 'standalone' disease, without a history and without determinants.

I don’t want to undersell the proposal so it’s worth pointing out that it is predicated on continuing with existing prevention programmes, but most of these also ignore the problems listed above! I am not opposed to the ambitious aim of testing and treating everyone, far from it. I just don't fancy our chances against HIV if we fail to address its determinants.


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