PrEP uptake and adherence in relation to HIV-1 incidence among Kenyan men who have sex with men

Abstract

Background: Data on HIV-1 incidence following programmatic pre-exposure prophylaxis (PrEP) uptake by men who have sex with men (MSM) are limited in sub-Saharan Africa.

Methods: Since June 2017, MSM participating in an ongoing cohort study in Kenya were offered daily PrEP, assessed for PrEP uptake and adherence, and evaluated for HIV-1 acquisition monthly. We determined tenofovir-diphosphate (TFV-DP) concentrations in dried blood spots 6-12 months after PrEP initiation, and tenofovir (TFV) concentrations and genotypic drug resistance in plasma samples when HIV-1 infection occurred. We assessed HIV-1 incidence by reported PrEP use.

Findings: Of 172 MSM, 170 (98·8%) were eligible for PrEP, 140 (82·4%) started it, and 64 (57·7%) reported PrEP use at end of study. Of nine MSM who acquired HIV-1 [incidence rate: 3·9 (95% confidence interval (CI), 2·0-7·4) per 100 person-years (PY)], five reported PrEP use at the time of HIV-1 acquisition [incidence rate: 3·6 (95% CI, 1·5-8·6) per 100 PY)] and four had stopped or had never started PrEP [incidence rate: 4·3 (95% CI, 1·6-11·3) per 100 PY]. Among 76 MSM who reported PrEP use, 11 (14·5%) had protective TFV-DP concentrations of ≥700 fmol/punch (≥4 tablets a week). Among the five MSM who acquired HIV-1 while reporting PrEP use, only one had detectable but low TFV concentrations in plasma and none had genotypic HIV-1 resistance.

Interpretation: HIV-1 incidence among MSM with access to programmatic PrEP was high and did not differ by reported PrEP use. Only one in seven MSM taking PrEP had protective tenofovir concentrations and four out of five MSM who acquired HIV-1 while reporting PrEP use had not taken it. Strengthened PrEP adherence support is required among MSM in Kenya.

Funding: This work was supported by the International AIDS Vaccine Initiative (IAVI).

Keywords: HIV-1 incidence; Kenya; MSM; Pre-exposure prophylaxis; Tenofovir.

Fig. 1

Flow of PrEP uptake and reported PrEP use among 179 MSM, Kilifi, Kenya, June 2017-June 2019. A total of 140 participants ever started PrEP including 9 who transferred in from another PrEP-providing facility. The median follow-up time for 59 participants who were LTFU was 7.3 months, interquartile range 2•5–13•8 months). PrEP=pre-exposure prophylaxis; LTFU=loss to follow-up.

Fig. 2

Frequency of PrEP dispensing by month of study visit among 179 MSM, Kilifi, Kenya, June 2017-June 2019. The figure illustrates the proportion of participants’ scheduled study visits at which PrEP was dispensed during follow-up. The table details the overall number of participants’ scheduled visits per calendar month, and the number of visits at which PrEP was dispensed. LTFU row shows the number of participants and the month at which they were LTFU. The number LTFU is not part of the scheduled visits. PrEP=pre-exposure prophylaxis, LTFU=loss to follow-up.

Fig. 3

HIV-1 incidence by reported PrEP use among 170 MSM, Kilifi, Kenya, June 2017- June 2019. PrEP=pre-exposure prophylaxis.

Fig. 4

Summary of HIV-1 acquisitions that occurred among nine participants during follow-up, Kilifi, Kenya, June 2017-June 2019. A reported inconsistent PrEP use before HIV-1 infection visit, had undetectable TFV concentrations at HIV-1 infection visit. B was not interested in PrEP at first offer due to fear of side effects. Discontinued PrEP one month after initiation due side effects. C was not interested in PrEP due to pill burden. D discontinued PrEP after travelling away from study area, restarted 2 months later. Reported good adherence and had detectable but low TFV concentrations (66•0 ng/Ml) in plasma at HIV-1 infection visit. E reported good adherence but had undetectable TFV concentrations at HIV-1 infection visit. F was not interested in PrEP, needed more time to decide. G experienced side effects following PrEP initiation from another PrEP-providing facility, restarted PrEP following further counselling at study clinic, had undetectable TFV concentrations at HIV-1 infection visit. H discontinued PrEP due to side effects one month following initiation from another PrEP-providing facility. Was willing to restart at study clinic but tested HIV-1 positive. I discontinued PrEP due to poor adherence two months following initiation from another PrEP-providing facility. Restarted at study clinic but reported inconsistent PrEP use due to travelling and other life challenges. Had undetectable TFV concentrations at HIV-1 infection visit. PrEP=pre-exposure prophylaxis; TFV=tenofovir.