# Chlamydia trachomatis Infection and Its Association with Human Papillomavirus Among Adolescent Girls and Young Women of Eastern Cape, South Africa

## TL;DR

This study found a high rate of Chlamydia and HPV co-infection among young women in rural South Africa, suggesting Chlamydia may affect HPV vaccine effectiveness.

## Contribution

The study reveals a significant association between Chlamydia trachomatis and HPV infection, including vaccine-targeted HPV types, in adolescent girls and young women.

## Key findings

- Chlamydia trachomatis prevalence was 29.4% among AGYW, with no age influence.
- HPV infection was more common among Chlamydia-positive individuals compared to the reverse.
- Chlamydia-positive AGYW had higher rates of HPV genotypes targeted by Cervarix®, Gardasil®4, and Gardasil®9 vaccines.

## Abstract

Background/Objectives: Adolescent girls and young women (AGYW) have a high burden of sexually transmitted infections (STIs). This study examined the prevalence of Chlamydia trachomatis, its association with human papillomavirus (HPV), and other associated factors among AGYW of rural communities. Methods: Secondary data on C. trachomatis, HPV, and linked questionnaires from 214 sexually active AGYW were used. Self-collected vaginal specimens were previously tested using the Allplex™ STI Essential Assay and Roche Linear Array HPV genotyping assay. Results: The overall prevalence of C. trachomatis was 29.4% (63/214), and it was not influenced by age. The majority of the AGYW were C. trachomatis negative and HPV positive (52.4%, 111/212), followed by being C. trachomatis and HPV co-infected (23.6%, 50/212), C. trachomatis and HPV co-negative (18.4%, 39/212) and least were C. trachomatis positive and HPV negative (5.7%, 12/212). There was an increased prevalence of being HPV infected among C. trachomatis individuals than being C. trachomatis positive among HPV positive individuals (RR: 2.60, 95% CI: 2.00–3.38, p < 0.0001). C. trachomatis positive AGYW had a significantly higher association of HPV types targeted by Cervarix® HPV vaccine (HPV-16 and/or -18) than C. trachomatis negatives (RR: 2.58, 95% CI: 1.37–4.82, p = 0.005), targeted by Gardasil®4 HPV vaccine (HPV-6, -11, -16 and/or -18; RR: 2.21, 95% CI: 1.32–3.65, p = 0.005) and Gardasil®9 HPV vaccine (HPV-6, -11, -16, -18, -31, -33, -45, -52 and/or -58; RR: 1.92, 95% CI: 1.37–2.67, p < 0.001). Conclusions: There was a high burden of C. trachomatis and HPV coinfection. C. trachomatis coinfection influenced HPV genotype prevalence and distribution, including those that are targeted by the current commercial HPV vaccines, suggesting that the high burden of C. trachomatis among AGYW may pose challenges to the ongoing HPV vaccination program. Integrated STI screening and prevention strategies are needed in rural South African settings.