PT - JOURNAL ARTICLE AU - Mónica S. Sierra AU - Sabrina H. Tsang AU - Carolina Porras AU - Rolando Herrero AU - Joshua N. Sampson AU - Bernal Cortes AU - John Schussler AU - Sarah Wagner AU - Loretto Carvajal AU - Wim Quint AU - Aimée R. Kreimer AU - Shangying Hu AU - Ana Cecilia Rodriguez AU - Byron Romero AU - Allan Hildesheim ED - , TI - Analysis of cervical HPV infections among unvaccinated young adult women to inform vaccine strategies in this age group: the Costa Rica HPV Vaccine Trial AID - 10.1136/sextrans-2022-055434 DP - 2022 Jul 16 TA - Sexually Transmitted Infections PG - sextrans-2022-055434 4099 - http://sti.bmj.com/content/early/2022/07/15/sextrans-2022-055434.short 4100 - http://sti.bmj.com/content/early/2022/07/15/sextrans-2022-055434.full AB - Introduction Human papillomavirus (HPV) vaccines protect against incident HPV infections, which cause cervical cancer.Objectives We estimated the prevalence and incidence of HPV infections in young adult women to understand the impact of an HPV vaccination programme in this population.Methods We collected cervical specimens from 6322 unvaccinated women, aged 18–37 years, who participated in the Costa Rica Vaccine Trial and its long-term follow-up. Women were followed for (median) 4.8 years and had (median) 4.0 study visits. Cervical specimens were tested for the presence/absence of 25 HPV genotypes. For each age band, we estimated the percentage of women with 1+ prevalent or 1+ incident HPV infections using generalised estimating equations. We also estimated the prevalence and incidence of HPV as a function of time since first sexual intercourse (FSI).Results The model estimated HPV incident infections peaked at 28.0% (95% CI 25.3% to 30.9%) at age 20 years then steadily declined to 11.8% (95% CI 7.6% to 17.8%) at age 37 years. Incident oncogenic HPV infections (HPV16/18/31/33/35/39/45/51/52/56/58/59) peaked and then declined from 20.3% (95% CI 17.9% to 22.9%) to 7.7% (95% CI 4.4% to 13.1%); HPV16/18 declined from 6.4% (95% CI 5.1% to 8.1%) to 1.1% (95% CI 0.33% to 3.6%) and HPV31/33/45/52/58 declined from 11.0% (95% CI 9.3% to 13.1%) to 4.5% (95% CI 2.2% to 8.9%) over the same ages. The percentage of women with 1+ incident HPV of any, oncogenic, non-oncogenic and vaccine-preventable (HPV16/18, HPV31/33/45, HPV31/33/45/52/58, and HPV6/11) types peaked <1 year after FSI and steadily declined with increasing time since FSI (p for trends <0.001). We observed similar patterns for model estimated HPV prevalences.Conclusion Young adult women may benefit from HPV vaccination if newly acquired vaccine-preventable oncogenic infections lead to cervical precancer and cancer. HPV vaccination targeting this population may provide additional opportunities for primary prevention.Trial registration number NCT00128661.Data are available upon reasonable request Participant data can be shared with outside collaborators for research to understand more about the performance of the HPV vaccine, immune response to the vaccine, and broader study factors associated with the natural history of HPV infection and risk factors for infection and disease. Outside collaborators can apply to access our protocols and data from the blinded phase of the Costa Rica Vaccine Trial (NCT00128661). Outside collaborators can apply for access to the data online. Data for the long-term follow-up phase are not yet available. For the trial summary, current publications, and contact information for data access see: Human Papillomavirus (HPV) Vaccine Trial in Costa Rica (CVT) - National Cancer Institute (https://dceg.cancer.gov/research/who-we-study/cohorts/costa-rica-vaccine-trial). The data that support the findings of this study are available from the corresponding author upon reasonable request.