Effect of initiation of antiretroviral drugs for HIV prevention or treatment on the vaginal microbiome of pregnant women in Malawi

The vaginal microbiota is associated with spontaneous preterm birth (sPTB). The impact of antiretroviral (ARV) drugs for HIV treatment or prevention on the vaginal microbiome during pregnancy remains uncertain.Using longitudinal data from the Tonse Pamodzi 2 study, we explored how HIV and ARV shape the vaginal microbiome among pregnant women in Lilongwe, Malawi. Pregnant women living with HIV (WLHIV) initiated three-agent antiretroviral therapy for HIV treatment (ART) while HIV-negative pregnant women initiated two-agent oral pre-exposure prophylaxis (PrEP) for HIV prevention. We explored associations between HIV serostatus, ARV initiation, the vaginal microbiome, and sPTB.