A study in Mexico has attempted to put an exact price on how much gay and bisexual men would have to be paid to change behaviours that put them at high risk of HIV.

The study, published in the European Journal of Health Economics, focussed on two sections of the population with particularly high prevalence of HIV infection: young gay men (estimated 20% HIV-positive) and male sex workers (estimated 30% HIV-positive).

The questionnaire revealed that for $288 (£180) per year, three quarters of those questioned would be willing to attend monthly talks on STI prevention, be regularly tested, and pledge to stay STI-free.

The Mexican government’s health care offers HIV treatment universally, at a cost of $5,000 to $7,000 (£3,200 – £4,500) per year.

Omar Galárraga, assistant professor of health services policy and practice and lead author of the study, said: “We’re trying to prevent HIV from spreading and we are trying to save money. We want to make sure that every dollar spent has the greatest impact.”

Mr Galárraga administered questionnaires to 1,745 men who fit those demographics. He used small hand-held computers to carry out the 40-minute long questionnaires in locations like clubs and red light districts. The computers made it appear that participants were simply texting, allowing them to discreetly take part in the study.

For the 5.1% of the male respondents who were sex workers the price was lower, around $156 (£100) per year.

“The target population seems generally very well-disposed to participate in these types of programs at prices which are consistent with other social programs currently in place in Mexico for preventing other health risks,” said Mr Galárraga.

He said that sex workers may have a more urgent need for money, hence the lower sum required to get them involved, and said that if they participated the money would compensate for the clients they might lose if they started requiring condom use during sex.

Since gathering the results of the study a pilot scheme for those willing to change their lifestyle to reduce risk has been launched, with 200 men participating.

Similar schemes which pay at-risk individuals to adopt safer behaviours have already been put to use in Mexico improving paediatric health care, as well as combating STIs in Malawi and Tanzania.