A View from Emerging Technology from the arXiv
The Complex Puzzle Of When to Start HIV Treatment
In a world of limited resources and expensive treatments, the question of who to treat and when needs careful assessment
Anti-retroviral therapy has revolutionised HIV treatment. The therapy involves a cocktail of drugs that together reduce the amount of HIV virus in the blood–the viral load–by three or four orders of magnitude.
That’s had a huge impact. The effect can be made to last at least seven years and probably indefinitely, it dramatically improves the prognosis for those who are HIV-positive and it vastly reduces the chances of the disease being passed on.
An important question is when to start an infected individual on this treatment.
It’s easy to imagine that it should start immediately on diagnosis but question is complicated by a number of additional factors that cause problems.
The side effects of the drugs can be severe and the regimen difficult to follow, which raises quality of life issues. The drugs are also expensive. When first developed, the treatment cost $13,000 a year and that put it more or less out of reach of all but the richest countries.
Because of these and other factors, various health organisation have given various different recommendations for when to start treatment. The World Health Organisation recommends treatment when the number of a type of white blood cells called CD4+-cells in the patient’s blood drops below a certain number, currently 350 per microlitre.
In the last year, however, the price of treatment has dropped even further, to about $150 per year. That changes things substantially for poorer countries but money is still scarce so the question remains–who should be treated and when?
Today, Brian Williams and pals at the South African Centre for Epidemiological Modelling and Analysis in Stellenbosch reveal the results of their analysis of this question.
“In an ideal world one would simply rank people in order of their predicted life expectancy and then start from those with the shortest life-expectancy and progressively include people with longer and longer life expectancies until the supply of drugs is exhausted,” they say.
Of course, in practice, things are more complicated because not all information is available for all HIV infected individuals when a decision has to be made. And in any case, CD4+ cell counts can vary widely in HIV-negative people and viral loads for a given level of infection can also vary widely for HIV-positive people.
Williams and co take these and other factors into account to decide when to begin treatment in three southern african countries: South Africa, Zimbabwe and Botswanna.
Their conclusion is this that treatment should begin as soon as an individual is found to be HIV positive. What’s more, they say that neither CD4+ cell counts nor viral load tests will significantly help to decide on whom to treat.
Williams and co finish with this paragraph:
“We show in this paper that if we are concerned to ‘do no harm’ then the use of CD4+ cell counts or viral load testing should be abandoned. If we also take into account the now accepted fact that the HIV-virus begins to compromise ones immune system from within weeks of infection, that the immune function, even with the best available drugs, shows significantly less recovery if one starts treatment later, the increase in mortality even among those with very high CD4+ cell counts, the very substantial evidence that early treatment stops transmission, and the cost and social savings that will undoubtedly accrue from early treatment,then regular testing and early treatment should now be made the standard of care.”
That should make it easy for authorities.
Ref: arxiv.org/abs/1208.3434: Anti-Retroviral Therapy For HIV: Who Should We Test And Who Should We Treat?
Couldn't make it to EmTech Next to meet experts in AI, Robotics and the Economy?Go behind the scenes and check out our video