Anti-HIV drugs unlikely to stop HIV spread

Researchers believe antiretroviral therapy (ART) will not be effective in stopping HIV epidemics even if it is made universally available in poorer countries, and that widespread use could even lead to an increase in the numbers infected with HIV.

Research published today in PLoS Medicine by a team from Imperial College London reveals a model which predicts how different strategies for increasing access to ART might affect HIV infection rates.

The modelling found that while ART reduces the viral load of infected individuals, thus decreasing the risk of HIV transmission, slowing disease progression allows patients to live longer, increasing the number infected and potentially the number of new infections they will cause.

Rebecca Baggaley, from Imperial College London, and one of the authors of the paper, said: “This model demonstrates that ongoing provision of prevention initiatives for stopping the spread of HIV is vital. Although ART may prove effective as part of an integrated treatment and prevention programme, including increased education and promotion of safe sex practices, it is unlikely to be effective alone.

“For a number of years, there has been significant debate about access to antiretroviral drugs, and how the high cost of these drugs has hindered many poorer countries’ attempts to combat HIV epidemics. While ART is undoubtedly effective at treating AIDS patients, particularly in richer countries, without public health interventions it will not prove effective in stopping the spread of HIV in poorer countries.”

The model also studied how ART treatment might affect behaviour. The researchers believe it could result in a greater spread of HIV by making infected individuals feel physically better, and more likely to be sexually active, but counselling of ART patients about risk behaviour could compensate for this to some extent. Therefore prevention initiatives aiming to decrease patients’ risk taking behaviour are even more relevant.

Rebecca Baggaley added: “This study could be important in helping to ensure that limited supplies of ART are used most effectively.”