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STIs and PrEP Uptake in Africa
Perspectives From Africa on New Studies Evaluating STI Incidence and PrEP Uptake Presented at CROI 2021

Released: April 15, 2021

Expiration: April 14, 2022

Nelly Mugo
Nelly Mugo, MBChB, MMed, MPH
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Recent studies have found that rates of sexually transmitted infections (STIs) and HIV are high and condom use is low among adolescent girls and young women in Kenya. At the Virtual 2021 Conference on Retroviruses and Opportunistic Infections (CROI 2021), we saw reports from several studies evaluating effective interventions and delivery modalities to interrupt the twin HIV and STI epidemics among young Kenyan women. These studies evaluated risk factors for STIs and assessed novel approaches to increase population level pre-exposure prophylaxis (PrEP) uptake, including in pregnant women. In this commentary, I summarize the findings and present my thoughts on the implications of these studies.

HSV-2 Acquisition and Contraceptive Methods Among African Women
Earlier observational studies suggested an increased risk for herpes simplex virus 2 (HSV-2) with intramuscular depo-medroxyprogesterone acetate (DMPA-IM) use. This prospective study evaluated HSV-2 acquisition among 3898 women who were confirmed HSV-2 seronegative and randomized to one of 3 contraceptive methods: DMPA-IM, a copper intrauterine device (IUD), or a levonorgestrel implant. Eligible women were aged 16-35 years, HIV seronegative, and seeking effective contraception. They were recruited from 12 sites in Kenya, the Kingdom of Eswatini, South Africa, and Zambia from 2015-2017.

HSV-2 infection rates were high in this population, with an overall incidence of 12.4/100 person-years. There was little difference in HSV-2 incidence across contraceptive methods, with 10.9/100 person-years among DMPA-IM users, 13.7/100 person-years among copper IUD users, and 12.7/100 person-years among levonorgestrel users. Compared with the copper IUD group, DMPA-IM users had an incidence rate ratio of 0.81 (95% CI: 0.67-0.99; P = .04). Although this difference is statistically significant, the upper confidence bound is almost 1.00.

This study demonstrates that HSV-2 incidence was high in this cohort but lowest among women using DMPA-IM compared with copper IUD and levonorgestrel. This contrasts with earlier observational study findings suggesting that DMPA-IM use was associated with increased HSV-2 risk. In my opinion, these newer data from the randomized trial support the on-going global efforts toward scale-up of long-acting contraceptive methods in HIV endemic regions. 

High Incidence of Subsequent STI Events Among Adolescent Girls in Kenyan Cohort
A cohort of 400 Kenyan adolescent girls aged 16-20 years, HIV and HSV-2 negative, with 1 or no previous sexual partner were enrolled on a prospective 5-year study designed to assess biological and behavioral risk factors for incident STIs. Participants were evaluated quarterly for Neisseria gonorrhea (GC), Chlamydia trachomatis (CT), Trichomonas vaginalis (TV), bacterial vaginosis, HSV-2, and HIV. After sexual debut, 299 sexually active girls were assessed for STI incidence and recurrence. At least 1 STI (CT, GC, HSV-2, TV) was detected in 56% of the girls, and 40% of those with an STI experienced 2 or more STI events. CT was the most common (85%) STI diagnosed and the most frequent recurrent infection, accounting for 72% of recurrent STI events. Diagnosis of bacterial vaginosis was associated with an increased risk of testing positive for any STI (CT, GC, TV, HSV-2) at the same visit, with an relative risk of 1.49 (95% CI: 1.09-2.03). Condom use remained low and was not correlated with STI risk. During the critical years near sexual debut, adolescent girls and young women demonstrated high incidence of multiple and recurrent STIs. This analysis shows the critical importance of education and outreach for young women before they begin sexual activity.

SEARCH Study: Social Networks and PrEP Uptake in Rural Kenya and Uganda
The SEARCH community trial was conducted in 32 rural communities in Uganda and Kenya from 2016-2017 with 16 PrEP intervention communities. PrEP was offered to persons who were assessed as at risk for HIV based on a serodiscordant partnership, an empiric risk score, or self-identification. This study assessed social network predictors of PrEP uptake during 1 year of population level HIV testing.

Among 220,332 individuals, 13,159 were assessed to be at high risk for HIV and were eligible for PrEP. Of these, 8898 (68%) had more than 1 social contact with a mean of 215 social contacts. Predictors of PrEP uptake were being female, HIV serodiscordant partnership, and age younger than 25 years.

Individuals with social network contacts who started PrEP were 57% more likely to initiate PrEP. This remained true for both same sex and opposite sex network contacts. Having a network contact who was an individual with HIV, after adjusting for serodiscordant couples, was not associated with a higher likelihood of PrEP uptake.

The results of this study suggest a possible new approach to foster PrEP uptake: evaluating and leveraging existing peer networks to strengthen social connections to other PrEP users.

PrIMA Study: Risk-Based vs Universal PrEP Delivery During Pregnancy
PrIMA is a cluster randomized trial comparing 2 models of PrEP delivery in 20 maternal child health clinics in western Kenya. Clinics were randomized to 2 approaches for delivering PrEP. The first—targeted PrEP—used the HIV risk score and an HIV self-test offered to the partner to identify individuals at risk for HIV infection. The second was a universal approach with standardized counseling and universal PrEP offered during pregnancy. 

Among 4447 pregnant women, 1877 (42%) were assessed to be at risk for HIV infection at baseline, with 51% in the targeted PrEP group vs 33% in the universal PrEP group. PrEP uptake, appropriate PrEP use, and median duration of PrEP use were similar in the targeted vs universal groups. There were no differences in perinatal HIV incidence (0.3 vs 0.4/100 patient-years). These results suggest that universal PrEP counseling is as effective as targeted PrEP services using HIV risk score during antenatal care.

Your Thoughts
How do these studies influence your thinking about STI risk and PrEP uptake, particularly among women, in Kenya? I encourage you to answer the polling question and post your thoughts and questions in the discussion box.

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How do new data from the PrIMA study influence your approach to PrEP counseling for pregnant women at risk for HIV?
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