Sixty-five Kenyans have contracted HIV while consistently taking the preventive drugs called Prep, the Ministry of Health has said.
If taken as prescribed, the pre-exposure prophylaxis drugs provide 100 per cent protection against HIV, so it is difficult to prove why the infections happened.
Nam-Aidsmap, a UK-based charity, in its analysis of the findings said some could have acquired HIV during a period of poor adherence or drug supply interruption.
Kenya rolled out Prep as a national programme in the public sector in May 2017, becoming the first African country to do so.
The last count done in Kenya in 2019 showed that 25,000 people were using Prep.
Medical experts say that there is no consistent data on how many people are using Prep, as a significant number takes it only to have risky and unprotected sex and then drop out.
The 65 cases happened between 2017 and 2021, but there could be more people who have become infected and were not documented.
The findings were presented online last week at the 11th International Aids Society Conference on HIV Science.
The authors said most of the people who turned positive had drug resistance mutations to the Prep drugs Emtricitabine and Tenofovir.
The researchers were unsure if the resistance came as a result of taking Prep or it may in some cases have already been there in the HIV that people acquired.
This drug resistance in the people who became positive was higher than seen in the general population.
“The high frequency of HIV drug resistance in HIV-infected individuals on PrEP exceeds background levels,” the researchers say in the study, also conducted in Zimbabwe, Eswatini and South Africa.
Some 79 Prep users in South Africa also turned positive within the same period, 36 in Zimbabwe and 28 in Eswatini.
All the infections came from among an estimated 104,000 people taking Prep in the four countries since 2017.
Researchers from the Kenya Medical Research Institute and the Ministry of Health's National Aids and STIs Control Programme were involved in the study.
Principal researcher Dr Urvi Parikh of Pittsburgh University said 35 per cent acquired HIV in the first three months on Prep, 40 per cent from three months to a year on it, and 18 per cent in people who had taken it for more than a year.
“But it does suggest that HIV infection on Prep is proving to be rare,” Nam-Aidsmap, a UK-based charity said in an analysis of the study.
The Prep users who turned positive were also tested for Prep drug levels in their blood, but this showed high drug levels, indicating good adherence.
“So some could have acquired HIV during a period of poor adherence or drug supply interruption, but when diagnosed had good adherence,” the Aidsmap analysis says.
The participants who provided a blood sample for analysis had a median age of 24 years, from a range of 16 to 67 years and 74 per cent were female.
Key populations included HIV serodiscordant couples (21 per cent), female sex workers (10 per cent), men who have sex with men (nine per cent), and transgender individuals (six per cent).
Prep failure is extremely rare if taken along with other prevention tools.
With hundreds of thousands of individuals using PrEP worldwide, only six cases have so far documented HIV infection among those with high adherence. - John Muchangi, The Star