Study shows vaginal microbiomes are not affected by oral PrEP

1 November 2022

A CAPRISA-led study, “Vaginal microbial shifts are unaffected by oral pre-exposure prophylaxis in South African women”, provided reassuring results that oral PrEP in women does not have a negative impact on the vaginal microbiome. This retrospective study within the CAPRISA 082 and CAPRISA 084 studies, published in the open access journal, Scientific Reports investigated the impact of daily oral tenofovir disoproxil fumarate in combination with emtricitabine (TDF-FTC) for PrEP on the vaginal microbiota in South African women. 
Researchers characterised the vaginal microbial communities of 64 PrEP and 36 non-PrEP group using the V4 region of the 16S rRNA sequencing in women enrolled in the CAPRISA 082 and CAPRISA 084 daily PrEP projects. Samples were selected at baseline, 3 months and 6 months.  At baseline, Lactobacillus iners or Gardnerella vaginalis dominant vaginal communities were observed in the majority of participants.  In cross sectional analysis, vaginal microbiota were not affected by the initiation and use of oral PrEP. 

Longitudinal analysis revealed that L. crispatus-dominant “cervicotypes 1 (CT1)” communities had high probability of remaining stable in PrEP group, but had a higher probability of transitioning to L. iners-dominant CT2 communities in non- PrEP group. L. iners-dominant communities were more likely to transition to communities associated with bacterial vaginosis (BV), irrespective of PrEP or antibiotic use. BV-linked CTs had a higher probability of transitioning to L. iners than L. crispatus dominant CTs and this shift was not associated with oral PrEP use. 

The researchers recommend regular screening for STIs and BV during PrEP care particularly in regions with high rates of HIV infection. 

For more reading see: Mazibuko-Motau N et al. Scientific Reports 2022. doi: 10.1038/s41598-022-20486-z