Prevalencia y determinantes de la infección por virus de papiloma humano en mujeres jóvenes de Guanacaste y Puntarenas, Costa Rica, 2004-2005.

OBJETIVO: Estimar la prevalencia e identificar determinantes de la infección por el virus del papiloma humano (VPH) en mujeres jóvenes (18-25 años). Material y métodos. Se analizaron datos de 5 871 mujeres sexualmente activas a quienes se les realizó una entrevista y toma de muestras cervicouterinas para detección de VPH y citología durante la visita de reclutamiento del Ensayo de Vacunación contra VPH16/18 en Costa Rica. Se calculó la prevalencia total para cualquier tipo de VPH y tipos oncogénicos, no oncogénicos y específicos, con intervalos de confianza al 95% (IC95%). Se utilizó regresión logística múltiple paso-a-paso para identificar determinantes asociados con la infección. RESULTADOS: La prevalencia total de VPH fue 50.0% (IC95% 48.8,51.3) y por tipos oncogénicos fue 33.8% (IC95% 32.6,35.0). El VPH-16 fue el tipo más prevalente (8.3%, IC95% 7.6,9.0). Los determinantes asociados con un alto riesgo de infección prevalente por VPH oncogénicos fueron no estar casada/unión libre, >1 compañero sexual, infección concomitante por Chlamydia trachomatis, y entre aquéllas con un único compañero sexual en su vida, un compañero con antecedente de múltiples compañeras sexuales. Conclusión. Se confirma la asociación de las infecciones por VPH oncogénicos con el comportamiento sexual de la mujer y se destacan los comportamientos del compañero sexual.

Cohort profile: evaluation of immune response and household transmission of SARS-CoV-2 in Costa Rica: the RESPIRA study.

PURPOSE: The RESPIRA cohort aims to describe the nature, magnitude, time course and efficacy of the immune response to SARS-CoV-2 infection and vaccination, population prevalence, and household transmission of COVID-19. PARTICIPANTS: From November 2020, we selected age-stratified random samples of COVID-19 cases from Costa Rica confirmed by PCR. For each case, two population-based controls, matched on age, sex and census tract were recruited, supplemented with hospitalised cases and household contacts. Participants were interviewed and blood and saliva collected for antibodies and PCR tests. Participants will be followed for 2 years to assess antibody response and infection incidence. FINDINGS TO DATE: Recruitment included 3860 individuals: 1150 COVID-19 cases, 1999 population controls and 719 household contacts from 304 index cases. The age and regional distribution of cases was as planned, including four age strata, 30% rural and 70% urban. The control cohort had similar sex, age and regional distribution as the cases according to the study design. Among the 1999 controls recruited, 6.8% reported at enrolment having had COVID-19 and an additional 12.5% had antibodies against SARS-CoV-2. Compliance with visits and specimens has been close to 70% during the first 18 months of follow-up. During the study, national vaccination was implemented and nearly 90% of our cohort participants were vaccinated during follow-up. FUTURE PLANS: RESPIRA will enable multiple analyses, including population prevalence of infection, clinical, behavioural, immunological and genetic risk factors for SARS-CoV-2 acquisition and severity, and determinants of household transmission. We are conducting retrospective and prospective assessment of antibody levels, their determinants and their protective efficacy after infection and vaccination, the impact of long-COVID and a series of ancillary studies. Follow-up continues with bimonthly saliva collection for PCR testing and biannual blood collection for immune response analyses. Follow-up will be completed in early 2024. TRIAL REGISTRATION NUMBER: NCT04537338.

Rationale and design of a double-blind randomized non-inferiority clinical trial to evaluate one or two doses of vaccine against human papillomavirus including an epidemiologic survey to estimate vaccine efficacy: The Costa Rica ESCUDDO trial.

HPV vaccination of adolescent girls is the most effective measure to prevent cervical cancer. The World Health Organization recommends that adolescent girls receive two doses of vaccine but only a small proportion of girls from regions with the highest disease burden are vaccinated because of cost and logistical considerations. Our Costa Rica HPV Vaccine trial suggested that one dose of the bivalent HPV vaccine provides robust and lasting protection against persistent HPV infections for over a decade. Data from a post-licensure trial of the quadrivalent vaccine in India also suggested that a single dose may be effective in reducing cervical cancer risk. To formally compare one versus two doses of the bivalent and nonavalent HPV vaccines, we implemented a large, randomized, double-blind trial to investigate the non-inferiority of one compared to two vaccine doses in the prevention of new HPV16/18 infections that persist 6 or more months. Bivalent and nonavalent vaccines will be evaluated separately. The trial enrolled and randomized (1:1:1:1 to 1- and 2-dose arms of the bivalent and nonavalent vaccines) 20,330 girls 12 to 16 years old residing in Costa Rica. Trial participants are followed every 6 months for up to 5 years. We also aim to estimate vaccine efficacy by comparing the rates of 6 month persistent infection in unvaccinated women with the rates in the follow-up visits of trial participants. We included one survey of unvaccinated women at the start of the study (N = 4452) and will include another survey concomitant with follow up visits of trial participants at year 4.5 (planned N = 3000). Survey participants attend two visits 6 months appart. Herein, we present the rationale, design, and enrolled study population of the ESCUDDO trial. ClinicalTrials.gov Identifier: NCT03180034.