Type-specific concurrent anogenital HPV detection among young women and MSM attending Dutch sexual health clinics.

OBJECTIVES: This study aimed to investigate type-specific concurrent anogenital human papillomavirus (HPV) detection and examine associations with concurrent detection. METHODS: Data from a Dutch repeated cross-sectional study among young sexual health clinic visitors (Papillomavirus Surveillance among STI clinic Youngsters in the Netherlands) between 2009 and 2019 were used. Cohen's kappa was used to assess the degree of type-specific concordance of HPV detection between anal and genital sites for 25 HPV genotypes for women and men who have sex with men (MSM) separately. Associations with type-specific concurrent HPV were identified. Receptive anal intercourse (RAI) was forced into the model to investigate its influence. RESULTS: Among women (n=1492), type-specific concurrent anogenital detection was common; kappa was above 0.4 for 20 genotypes. Among MSM (n=614), kappa was <0.4 for all genotypes. The only significant association with type-specific concurrent anogenital detection among women was genital chlamydia (adjusted OR 1.5, 95% CI 1.1 to 2.2). RAI was not associated. CONCLUSIONS: Type-specific concurrent anogenital HPV detection was common among young women, and uncommon among MSM. For women, concurrent HPV detection was associated with genital chlamydia. Our results are suggestive of autoinoculation of HPV among women.

Timing of progression from Chlamydia trachomatis infection to pelvic inflammatory disease: a mathematical modelling study.

BACKGROUND: Pelvic inflammatory disease (PID) results from the ascending spread of microorganisms from the vagina and endocervix to the upper genital tract. PID can lead to infertility, ectopic pregnancy and chronic pelvic pain. The timing of development of PID after the sexually transmitted bacterial infection Chlamydia trachomatis (chlamydia) might affect the impact of screening interventions, but is currently unknown. This study investigates three hypothetical processes for the timing of progression: at the start, at the end, or throughout the duration of chlamydia infection. METHODS: We develop a compartmental model that describes the trial structure of a published randomised controlled trial (RCT) and allows each of the three processes to be examined using the same model structure. The RCT estimated the effect of a single chlamydia screening test on the cumulative incidence of PID up to one year later. The fraction of chlamydia infected women who progress to PID is obtained for each hypothetical process by the maximum likelihood method using the results of the RCT. RESULTS: The predicted cumulative incidence of PID cases from all causes after one year depends on the fraction of chlamydia infected women that progresses to PID and on the type of progression. Progression at a constant rate from a chlamydia infection to PID or at the end of the infection was compatible with the findings of the RCT. The corresponding estimated fraction of chlamydia infected women that develops PID is 10% (95% confidence interval 7-13%) in both processes. CONCLUSIONS: The findings of this study suggest that clinical PID can occur throughout the course of a chlamydia infection, which will leave a window of opportunity for screening to prevent PID.