Integrated HIV and STIs response: Trends in syphilis incidence and uptake of oral pre-exposure prophylaxis in Zambia.

Background: Pre-exposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) was introduced in Zambia to prevent transmission, but it does not protect against sexually transmitted infections (STIs) such as syphilis. Globally, STIs have risen alongside PrEP rollout, posing significant public health concerns that require urgent attention and targeted intervention strategies.

Aim: We examined trends in syphilis incidence and assessed its association with PrEP use, given the increasing global burden of STIs, including among PrEP users between 2021 and 2023.

Setting: Among individuals in Zambia.

Methods: A retrospective database analysis of secondary data was conducted using District Health Information Software 2 (DHIS2), the Ministry of Health's primary data system. Microsoft^® Excel and Stata were used for descriptive statistics and regression analysis to examine potential associations.

Results: From 2021 to 2023, syphilis cases (199 273) and PrEP initiation (436 460) increased annually. Syphilis cases rose from 22% to 46%, while PrEP initiation grew from 22% to 48%. We found a positive association between syphilis incidence and PrEP initiation, with each unit increase in PrEP initiation corresponding to a 0.33-unit rise in syphilis cases (p < 0.001; 95% confidence interval [CI]: 0.25-0.4), underscoring this relationship.

Conclusion: This analysis found a significant positive link between syphilis incidence and PrEP initiation, emphasising the need for integrated HIV and STI management to enhance public health interventions.

Contribution: This study provides valuable insights for policy and programme implications; it highlights the importance of integrating STI prevention into HIV prevention service delivery; an integrated approach is critical to ensure that the country does not regress the achievements made towards HIV epidemic control.