Broader access to antiretroviral drugs is likely to be ineffective in stopping the HIV epidemic and could even lead to an increase in the numbers affected with the virus, according to researchers at Imperial College London in the UK.

A mathematical model was developed by the team to predict how different strategies for increasing access to HIV drugs might affect infection rates. Using this, they found that although antitretroviral therapy would reduce viral load and the chances of transmission in people infected with HIV, their longer lifespans and slower disease progression meant that the number of infected individuals, and their chances of passing on the infection, would increase.

Moreover, the model also suggested that greater access to HIV drugs could increase the spread of the virus by encouraging infected people to be more sexually active.

Rebecca Baggaley, one of the authors of the paper, said the study showed that antiretrovirals is not a substitute for prevention initiatives, such as increased education and promotion of safe sex practices.

“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,” she said.

Without public health interventions, [antiretroviral therapy] will not prove effective in stopping the spread of HIV in poorer countries,” said Baggaley. The model could be useful in ensuring that limited supplies of HIV drugs are used most effectively, she added.

The study is published in the open-access journal PLoS Medicine