A team of researchers from WHO has used computer modelling to show that universal voluntary HIV testing, combined with immediate antiretroviral treatment (ART) following a positive diagnosis, would reduce HIV cases in a severe generalised epidemic from 20 per 1000 people to 1 per 1000 people within 10 years. The findings are reported in an Article published Online first and in an upcoming edition of The Lancet , written by Dr Reuben Granich, Department of HIV/AIDS, WHO, Geneva, Switzerland and colleagues.
Roughly 3 million people worldwide had received ART by the end of 2007, but an estimated 6.7 million were still in need of treatment and a further 2.7 million became infected in 2007. The authors used mathematical modelling to explore the effect on the case reproduction number and long-term dynamics of the HIV epidemic of testing all people in their test community (aged 15 years or over) for HIV every year and starting HIV antiretroviral treatment immediately after a positive diagnosis. They used data from South Africa as a test case for a generalised epidemic, and the model assumed all HIV transmission was heterosexual.
They found that the studied strategy could greatly accelerate the transition from the current endemic phase, in which most adults with HIV are not receiving ART, to an elimination phase, in which most adults are on ART within five years. Furthermore, the strategy could reduce HIV case to 1 per 1000 people within 10 years of full implementation, a fall of 95%. The authors say: "Instead of dealing with the constant pressure of newly infected people, mortality could decrease rapidly and the epidemic could begin to resemble a concentrated epidemic with particular populations remaining at risk. The focus of control would switch from making ART available to people with greatest need to providing support and services for those who are receiving ART. Transmission could be reduced to low levels and the epidemic could go into a steady decrease towards elimination as those receiving ART grew older and died.
"Although other prevention interventions, alone or in combination, could substantially reduce HIV incidence, our model suggests that only universal voluntary HIV testing and immediate initiation of ART could reduce transmission to the point at which elimination might be feasible by 2020 for a generalised epidemic, such as that in South Africa. This analysis lends support to, and extends, earlier analyses suggesting that rapid scale-up of conventional ART approaches could greatly reduce mortality and have a substantial effect on HIV incidence."
They conclude: "Universal voluntary HIV testing and immediate ART, combined with present prevention approaches, could have a major effect on severe generalised HIV/AIDS epidemics. This approach merits further mathematical modelling, research, and broad consultation."
In the first of two accompanying Comments, Dr Kevin De Cock, WHO, Geneva, Switzerland (who was also one of the Article authors), and other colleagues from WHO emphasise that this modelling exercise does not represent policy or technical guidance, but a call for research and discussion. They add WHO is committed to promoting consultation among countries and stakeholders about the pressing biomedical issue of ART for HIV prevention.
They say: "Advantages of immediate treatment on diagnosis could include: simplified clinical management; reduction in the high mortality rates from late diagnosis; control of HIV-associated tuberculosis; and effective prevention of mother-to-child transmission of HIV, including through breastfeeding." Furthermore they note: "Feasibility is challenged by: weak health systems and inadequate health personnel; choice of appropriate drug regimens; treatment adherence; drug toxicity; drug resistance and need for durable second and third-line regimens; the logistics, reliability, and acceptability of regularly testing a whole population for HIV infection; and behavioural risk compensation."
In the second Comment, Professor Geoffrey P Garnett, Imperial College London, UK, says: "The suggested strategy would reflect public health at its best and its worst. At its best, the strategy would prevent morbidity and mortality for the population, both through better treatment of the individual and reduced spread of HIV. At its worst, the strategy will involve over-testing, over-treatment, side-effects, resistance, and potentially reduced autonomy of the individual in their choices of care. The individual might gain no personal benefit from testing and early treatment, but they would benefit from protecting partners—and who could object to that, unless they were recklessly exposing others to infection? It is easy to see how enforced testing and treatment for the good of society would follow from such an argument. Partial success would lead to infection becoming concentrated in those with a high risk, with an increased danger of stigma and coercion."
Dr Reuben Granich, Department of HIV/AIDS, WHO, Geneva, Swtizerland
T) +41 22 791 1459
E) granichr@who.int
Dr Kevin De Cock, WHO, Geneva, Switzerland
T) +41 22 791 3910
E) Decockk@who.int
Dick Thompson, WHO Press Office
T) +41 79 475 5534
E) thompsond@who.int
Professor Geoffrey P Garnett, Department of Infectious Disease Epidemiology, Imperial College London, UK
T) +44 (0)7872 850 299
E) g.garnett@imperial.ac.uk
For full Article and both Comments, please see: http://press.thelancet.com/whohivmodelfinal.pdf
The Lancet