(P144) STI prevalence among young adults diagnosed with HIV in childhood and adulthood: a cross-sectional survey in Zimbabwe

Background: Young adults (aged 18-24 years) in Zimbabwe may have acquired HIV perinatally or horizontally. The sexual and reproductive health (SRH) needs of these groups may be different. We aimed to compare the characteristics and STI prevalence of young people who were diagnosed with HIV in childhood and adulthood, as a proxy for route of HIV acquisition i.e. perinatally vs horizontally.

Methods: A cross-sectional representative population-based survey of young people aged 18-24 years was conducted in 2 provinces in Zimbabwe, to ascertain the outcome of a cluster-randomised trial of community-based integrated HIV and SRH services. Participants were asked their HIV status, the date of their HIV diagnosis if positive, and whether they were diagnosed as a child. A urine sample was taken from a randomly selected 50% of participants and tested for STIs including chlamydia (CT), gonorrhoea (NG) and trichomoniasis (TV). Generalised linear log-binomial modelling was used to estimate the association between HIV diagnosis period and STI prevalence, adjusting for age (18-20 vs ≥21 years), sex and sexual debut.

Results: 11818 participants were enrolled; 8318 reported their HIV status at last test and 309 (3.7%) were known HIV positive, of whom 156 had an STI test result. 155/308 (45.7%) said they had been diagnosed as children (1 did not answer). HIV diagnosis was associated with increased risk of an STI (adjusted risk ratio[aRR]=0.37, 95%CI 0.15-0.59, p=0.001) and with NG and CT, compared to non-diagnosed participants.

Median age of diagnosis for those diagnosed in childhood was 8 years (IQR 2-12) compared to 21 years (IQR 19-24) in the remaining 153 participants. HIV acquisition in adulthood was associated with increased risk of NG (aRR=2.06, 95%CI 0.00-4.13, p=0.05) compared to HIV acquisition in childhood, but there was no association with CT, TV, or overall STI infection.

Conclusion: Young adults living with HIV have increased prevalence of STIs and should receive STI screening at HIV diagnosis. Those who acquired HIV in adulthood are at increased risk of NG compared to their peers who acquired HIV perinatally.