A pill meant to shield people from contracting HIV could be indirectly fuelling promiscuity by encouraging unprotected sex, a new study shows.
The study also showed that the introduction of the pill, known as pre-exposure prophylaxis (PrEP), has coincided with increase in other sexually transmitted infections like chlamydia and syphilis, a sign that condom use had dropped.
According to the study, people are practising risk compensation, which means that they generally care less when they sense they have protection or are more careful when in deeper risk.
"When seat belt laws came into effect, some studies suggested drivers became more likely to speed or drive recklessly.
"It is the same thing happening among people at risk of HIV. Now that they can take drugs to protect themselves from the virus, they are not using condoms," says the study, whose findings were published in the Lancet HIV on Monday.
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It surveyed 17,000 men who have sex with men in Sydney and Melbourne cities between 2013 and 2017.
The new study analysed the uptake and effect of PrEP, particularly on condom use by gay and bisexual men.
The findings revealed that consistent condom use dropped from 46 per cent to 31 per cent in men who reported having anal sex with casual partners.
A rapid increase in PrEP use by gay and bisexual men in Melbourne and Sydney was accompanied by an equally rapid decrease in consistent condom use.
Last year and amid much fanfair, Kenya launched PrEP in a bid to reduce new HIV infections by 75 per cent by 2019.
A year later, experts now warn that the uptake is still lower than expected. When taken as prescribed, PrEP can reduce the risk of contracting HIV by up to 90 per cent.
"PrEP is not for everyone and it's not to be taken for life. Individuals who perceive themselves to be at risk should visit a healthcare facility for a HIV test and have a discussion with the healthcare provider," said Dr Nelly Mugo, the principal research scientist at the Kenya Medical Research Institute and the lead researcher on the PrEP efficacy trials conducted in Kenya.
Currently, the drug is only available for use upon prescription. "If a non-infected person takes PrEP, then the virus is killed if it enters their body.
This means it doesn't have a chance to hide in reservoirs, and so it is harder for that person to become infected," explained Dr Mugo.
However, PrEP is only meant for specific populations at high risk of infection like young women, serodiscordant couples and sex workers and youth.
Experts, however, warn that PrEP is not a magic bullet, and must be taken in combination with safe sex practices like use of condoms. Moreover, after a month on PrEP one requires further screening to check levels of the drug in their blood and to check if they contracted HIV while on the drug.