Six-country African PrEP study achieves high levels of persistence and good adherence in young women

A demonstration project of oral PrEP for young women, conducted in six African countries with high HIV prevalence, achieved high levels of PrEP uptake and persistence, and good levels of adherence among its 3000 participants.

Dr Brenda Mirembe of Makerere University told the Conference on Retroviruses and Opportunistic Infections (CROI 2024) that the use of a rapid urine test to measure tenofovir levels and confirm adherence was generally seen as supportive by the participants. But despite high levels of PrEP use, HIV annual incidence remained quite high at 1.38% – or one infection in every 72 participants a year. This is not much lower than the current estimated incidence among young women in South Africa (about 1.5% a year).

The INSIGHT cohort is a multi-site demonstration study of PrEP among young women in 14 sites in South Africa and one each in Eswatini, Kenya, Malawi, Uganda and Zambia. Data were collected between August 2022 and August 2023, though follow-up time for each individual was six months.

It screened 3342 women. A total of 142 turned out to have HIV (4.2%) and 113 were ineligible for other reasons, leaving 3087 participants. Their average age was 24. Most (96%) had a primary partner and few had had more than two partners in the past three months. Thirty-one per cent had a bacterial STI, which was treated. Nearly one in seven (13.6%) had used PrEP before, reflecting wider uptake and availability in Africa.

There was good uptake of PrEP, and persistence in using it, for the six months of the study. Ninety-two per cent of participants completed all four study visits (at enrolment and months one, three and six) and 90% of them received every refill of PrEP.

The original plan had been to ask every participant to take a urine test for tenofovir at each study visit. This assay has been available for over a decade and was also used to measure adherence in the Partners PrEP and  iPrEX OLE studies. It can give a result within a minute and gives a positive result for tenofovir levels of over 1500 nanograms per millilitre of urine. A positive result indicates that tenofovir has been taken over the last six days and correlates with levels seen in dried blood spots and hair. Positive results were predictive of participants remaining HIV negative in the two studies mentioned above.

The tests were donated and there was an interruption in supply during the study. So in the end tests were conducted with an average of 60% of participants: 67% at month one, 33% at month three, and 80% at month six. These indicated recent adherence of 72% at month one, 71% at month three, and 67% at month six.

Although 62% of participants described typical side effects of PrEP such as nausea, most said that PrEP had had a positive impact on their lives. Ninety-one per cent said they were less worried about getting HIV and a similar proportion felt ‘freer’ when having sex. Ninety-seven per cent agreed that it generally helped to reduce anxiety. Ninety-three per cent had disclosed their PrEP use to others, though 25% of participants had experienced at least one incident of unintended PrEP disclosure.

The top three adherence challenges for the participants were ‘simply forgetting’ (cited by 69%), forgetting one’s pills when travelling (43%) and not taking the pills because of not feeling at risk (40%).

The urine test was seen by the participants as a positive reinforcement of adherence. Only 42% of women who first took the test at month three or six tested positive for tenofovir but 71% who had taken one or two prior tests had detectable drug. Sixty-four per cent described it as a motivator to take PrEP. On the other hand, only 19% said that they had had help from an adherence counsellor to take their pills.

There were limitations to the study. The follow-up time of six months was not long, and receipt of urine tests was not randomly allocated, so those who did receive one may have been unrepresentative. The six-day time-span of the test means that very recent dosing (‘white coat’ dosing, when participants take a drug just before a clinic visit) could not be ruled out, and longer-term patterns of persistence that show up with dried blood spots or hair tests could also not be established definitively.

The approximately 70% adherence and high persistence demonstrated was better than that seen in most previous studies in African women, but still 1.4% of participants caught HIV. This compares with 1.8% in the oral PrEP arm of the HPTN 084 study, where adherence was 42%. This shows that although PrEP is helping to protect young women in Africa from HIV, adherence will have to be still higher to protect them more fully.