Study cohort
The ECHO Trial (clinicaltrials.gov identifier: NCT02550067) compared the relative HIV-1 incidence among women randomized to Cu-IUD, LNG implant, or DMPA-IM as the primary outcome. This nested mucosal sub-study aimed to evaluate the impact of these contraceptives on genital tract microbiota and immunity. The primary endpoints for this mucosal substudy were changes in Th17 cell frequency, microbial diversity and vaginal cytokine concentrations induced by hormonal contraceptive initiation. Secondary outcomes were changes associated with later HIV seroconversion. Eligibility and randomization procedure for the parent trial is described in detail elsewhere