A man on PrEP has been diagnosed with HIV.
Doctors in San Francisco diagnosed the man – who is the third documented case in the US in which the HIV-prevention drug has failed – and said he had a rare strain of drug-resistant HIV.
The man began the PrEP program back in 2016 and following DNA from hair samples, the man adhered correctly to the program without missing a dose of the drug.
But doctors have said that his infection was due to a HIV-positive partner who stopped taking his own medication.
The patient’s partner carried a rare drug-resistant strain of HIV and as his viral load began to increase, he passed it on to his partner who was taking the drug.
The levels of Truvada in the PrEP-taking partner’s body were not high enough to fight the drug-resistant of the virus.
PrEP still remains more than 99.9 per cent effective in the transmission of the HIV compared to other methods including condoms.
Dr Robert Grant, of the University of California San Francisco, said: “We known PrEP is greater than 99 per cent effective.
“There are some cases where HIV will break through. We only have a handful of cases now, and next year, we’ll probably have a handful more.
“Fortunately, these cases are caught early, treated, and suppressed quickly. The person goes from taking one pill a day to one pill a day. The biggest difference is stigma.”