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PurposeThe 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.ParticipantsFrom 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 dateRecruitment 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 plansRESPIRA 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 numberNCT04537338.

In 2022, WHO recommended single-dose human papillomavirus (HPV) vaccination as an alternative schedule to multidose regimens. To provide evidence to support approval of a single-dose indication for the AS04-adjuvanted bivalent HPV vaccine (Cervarix, GlaxoSmithKline), we investigated whether the immune response to a single dose of the bivalent vaccine in girls aged 9–14 years was non-inferior to the immune response to three doses of the quadrivalent HPV vaccine (Gardasil-4, Merck) in women aged 18–25 years, a dose and population combination with demonstrated efficacy. This non-randomised, open-label, immunobridging trial enrolled girls aged 9–14 years and women aged 18–25 years in Guanacaste Province, Costa Rica. Healthy girls aged 9–14 years received one dose of bivalent HPV vaccine, whereas healthy women aged 18–25 years received three doses of quadrivalent HPV vaccine at 0, 2, and 6 months. The primary endpoint was geometric mean concentrations (GMCs) of HPV-specific serum antibodies measured by a validated virus-like-particle-based ELISA assay at 36 months. The per-protocol cohort included participants who received the correct number of doses within the predefined vaccination windows, had blood collected at the 36-month study visit for the final analysis, were seronegative at baseline for the specified HPV type, and did not receive additional HPV vaccine doses outside the study. Non-inferiority was declared when the lower bound of the 96% CI for the GMC ratio was greater than or equal to 0·67 for HPV-16 and HPV-18. Seropositivity was a secondary objective. Safety was analysed in the total vaccinated population. This trial is registered with ClinicalTrials.gov, NCT03728881, and is complete. Between April 1 and Aug 16, 2019, 620 girls and 620 women were enrolled and received their first HPV vaccination. After exclusions, 539 girls and 366 women were HPV-16 seronegative at enrolment and were included in the HPV-16 per-protocol cohort; 523 girls and 373 women were HPV-18 seronegative at enrolment and were included in the HPV-18 per-protocol cohort. At 36 months, the HPV-16 GMC was 21·4 international units (IU)/mL (95% CI 19·7–23·3) in girls in the single-dose bivalent vaccine group and 42·9 IU/mL (95% CI 38·9–47·3) in women in the three-dose quadrivalent vaccine group, resulting in a GMC ratio of 0·50 (96% CI 0·44–0·57); the HPV-18 GMC was 8·0 IU/mL (95% CI 7·4–8·8) in girls in the single-dose bivalent vaccine group and 7·2 IU/mL (95% CI 6·4–8·1) in women in the three-dose quadrivalent vaccine group, resulting in a GMC ratio of 1·11 (96% CI 0·95–1·29). At 36 months, 538 (99·8%, 95% CI 99·1–100) of 539 girls in the single-dose bivalent vaccine group were seropositive for HPV-16 compared with 366 (100%, 99·2–100) of 366 women in the three-dose quadrivalent vaccine group (p=1·00). The proportion of participants who were seropositive for HPV-18 was higher in the single-dose bivalent vaccine group (517 [98·9%, 95% CI 97·6–99·5] of 523 girls) than in the three-dose quadrivalent vaccine group (358 [96·0%, 93·6–97·6] of 373 women; p=0·0065). Two serious adverse events were reported in 620 girls and 13 serious adverse events were reported in 620 women; all serious adverse events were deemed to be unrelated to HPV vaccination. Non-inferior antibody responses for the single-dose bivalent HPV vaccine were seen for HPV-18 but not HPV-16, which would be insufficient evidence to motivate regulatory change, even though seropositivity approached 100% in the follow-up phase and the observed antibody concentrations were similar to protective levels seen in previous trials. Trials that directly evaluate protection afforded by single-dose HPV vaccination against persistent HPV infection will definitively address the level of protection afforded by single-dose HPV vaccination. National Cancer Institute, Cancer Research UK, and the Gates Foundation. For the Spanish translation of the abstract see Supplementary Materials section.

The Costa Rica Vaccine Trial (CVT), a phase III randomized clinical trial, provided the initial data that one dose of the HPV vaccine could provide durable protection against HPV infection. Although the study design was to administer all participants three doses of HPV or control vaccine, 20% of women did not receive the three-dose regimens, mostly due to involuntary reasons unrelated to vaccination. In 2011, we reported that a single dose of the bivalent HPV vaccine could be as efficacious as three doses of the vaccine using the endpoint of persistent HPV infection accumulated over the first four years of the trial; findings independently confirmed in the GSK-sponsored PATRICIA trial. Antibody levels after one dose, although lower than levels elicited by three doses, were 9-times higher than levels elicited by natural infection. Importantly, levels remained essentially constant over at least seven years, suggesting that the observed protection provided by a single dose might be durable. Much work has been done to assure these non-randomized findings are valid. Yet, the group of recipients who received one dose of the bivalent HPV vaccine in the CVT and PATRICIA trials was small and not randomly selected nor blinded to the number of doses received. The next phase of research is to conduct a formal randomized, controlled trial to evaluate the protection afforded by a single dose of HPV vaccine. Complementary studies are in progress to bridge our findings to other populations, and to further document the long-term durability of antibody response following a single dose.

IntroductionHuman papillomavirus (HPV) vaccines protect against incident HPV infections, which cause cervical cancer.ObjectivesWe estimated the prevalence and incidence of HPV infections in young adult women to understand the impact of an HPV vaccination programme in this population.MethodsWe 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).ResultsThe 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.ConclusionYoung 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.

The HPV vaccine has shown sustained efficacy and consistent stabilization of antibody levels, even after a single dose. We defined the HPV16-VLP antibody avidity patterns over 11 years among women who received one- or three doses of the bivalent HPV vaccine in the Costa Rica HPV Vaccine Trial. Absolute HPV16 avidity was lower in women who received one compared to three doses, although the patterns were similar (increased in years 2 and 3 and remained stable over the remaining 8 years). HPV16 avidity among women who were HPV16-seropositive women at HPV vaccination, a marker of natural immune response to HPV16 infection, was significantly lower than those of HPV16-seronegative women, a difference that was more pronounced among one-dose recipients. No differences in HPV16 avidity were observed by HPV18 serostatus at vaccination, confirming the specificity of the findings. Importantly, point estimates for vaccine efficacy against incident, six-month persistent HPV16 infections was similar between women who were HPV16 seronegative and seropositive at the time of initial HPV vaccination for both one-dose and three-dose participants. It is therefore likely that this lower avidity level is still sufficient to enable antibody-mediated protection. It is encouraging for long-term HPV-vaccine protection that HPV16 antibody avidity was maintained for over a decade, even after a single dose.

Background Antibodies to SARS-CoV-2 are essential for protection or reduction in severity of subsequent disease. We studied antibody responses to spike protein receptor-binding domain (S1-RBD) and nucleocapsid (N) in a population-based sample of COVID-19 cases in Costa Rica. Methods As part of the RESPIRA study, we selected an age-stratified random sample of PCR-confirmed COVID-19 cases diagnosed from March 2020 to July 2021. Antibodies were determined with multiplex serology in 794 unvaccinated subjects diagnosed 3 days to 17 months before recruitment to investigate immune response to natural infection. In addition, neutralizing antibodies were determined in 136 randomly selected participants. We estimated antibody positivity and GMTs by time since diagnosis and explored determinants using multivariate regression. Results Most participants tested 15–29 days after PCR diagnosis were seropositive for N (90%) and S1-RBD antibodies (96%) and had the highest GMTs for both antibodies. Only 42% of subjects tested one year after infection were seropositive for N antibodies, compared to 97% for S1-RBD. GMTs for neutralizing antibodies peaked 15–89 days after infection and declined but remained positive for 95% of subjects thereafter. In multivariate models, antibodies were significantly higher among men and increased with age and severity of the clinical presentation. The correlation of multiplex and neutralizing antibodies was high (0.72 [95% CI = 0.63–0.79]) and stronger among women. Conclusions A robust immune response against N and S1-RBD is elicited by COVID-19 a few days after infection. While S1-RBD antibodies are present after > 1 year, N antibodies decline significantly. Antibody levels are higher in men and increase with age and severity of disease. The different immune response patterns by sex warrant further investigation. Trial registration RESPIRA Study ClinicalTrials.gov ID: NCT04537338 (3 September 2020).

Abstract Background Human papillomaviruses (HPV) cause over 500 000 cervical cancers each year, most of which occur in low-resource settings. Human papillomavirus genotyping is important to study natural history and vaccine efficacy. We evaluated TypeSeq, a novel, next-generation, sequencing-based assay that detects 51 HPV genotypes, in 2 large international epidemiologic studies. Methods TypeSeq was evaluated in 2804 cervical specimens from the Study to Understand Cervical Cancer Endpoints and Early Determinants (SUCCEED) and in 2357 specimens from the Costa Rica Vaccine Trial (CVT). Positive agreement and risks of precancer for individual genotypes were calculated for TypeSeq in comparison to Linear Array (SUCCEED). In CVT, positive agreement and vaccine efficacy were calculated for TypeSeq and SPF10-LiPA. Results We observed high overall and positive agreement for most genotypes between TypeSeq and Linear Array in SUCCEED and SPF10-LiPA in CVT. There was no significant difference in risk of precancer between TypeSeq and Linear Array in SUCCEED or in estimates of vaccine efficacy between TypeSeq and SPF10-LiPA in CVT. Conclusions The agreement of TypeSeq with Linear Array and SPF10-LiPA, 2 well established standards for HPV genotyping, demonstrates its high accuracy. TypeSeq provides high-throughput, affordable HPV genotyping for world-wide studies of cervical precancer risk and of HPV vaccine efficacy.

Etiological differences among breast cancer (BC) subtypes have not been clearly established, especially among young women in Latin America. This study examined the relationship between reproductive factors and BC subtypes among 288 BC cases (20–45 years) and population-based matched controls in four Latin American countries. Immunohistochemistry was determined centrally. Associations between BC and reproductive factors were determined. Older age at first full-term pregnancy (FFTP) (Odds Ratio (OR) = 1.11; 95% Confidence Interval (CI), 1.04–1.19 per year), longer time between menarche and FFTP (OR = 1.12; 95%CI: 1.04–1.20 per year), and older age at last pregnancy (OR = 1.10; 95%CI, 1.02–1.19 per year) were associated with an increased risk of estrogen receptor positive (ER+) tumors (n = 122). Ever pregnant (OR = 0.35; 95%CI, 0.13–0.96), number of childbirths (OR = 0.64; 95%CI, 0.47–0.87 per child), time since last birth (OR = 0.92; 95%CI, 0.85–0.99 per year), and history of breastfeeding (OR = 0.23; 95%CI, 0.09–0.58) were inversely associated with the risk of ER+ tumor. Older age at menarche (OR = 0.63; 95%CI, 0.45–0.89 per year) and longer duration of breastfeeding (OR = 0.97; 95%CI, 0.94–1.01 per month) were inversely associated with estrogen receptor negative (ER-) tumors (n = 48). Reproductive factors may be differentially associated with BC subtypes in young Latin American women.

Cumulating evidence in Caucasian women suggests a positive association between height and premenopausal breast cancer risk and a negative association with overall adiposity; however data from Latin America are scarce. We investigated the associations between excess adiposity, body shape evolution across life, and risk of premenopausal breast cancer among 406 cases (women aged 20–45) and 406 matched population-based controls from Chile, Colombia, Costa Rica, and Mexico. Negative associations between adult adiposity and breast cancer risk were observed in adjusted models (body mass index (BMI): Odds ratio (OR) per 1 kg/m 2  = 0.93; 95% confidence interval = 0.89–0.96; waist circumference (WC): OR per 10 cm = 0.81 (0.69–0.96); hip circumference (HC): OR per 10 cm = 0.80 (0.67–0.95)). Height and leg length were not associated with risk. In normal weight women (18.5 ≤ BMI < 25), women with central obesity (WC > 88 cm) had an increased risk compared to women with normal WC (OR = 3.60(1.47–8.79)). Residuals of WC over BMI showed positive associations when adjusted for BMI (OR per 10 cm = 1.38 (0.98–1.94)). Body shape at younger ages and body shape evolution were not associated with risk. No heterogeneity was observed by receptor status. In this population of Latin American premenopausal women, different fat distributions in adulthood were differentially associated with risk of breast cancer.

We report the rationale, design, methods and details of participation of a community-based, double-blind, randomized clinical trial of an HPV 16 and 18 vaccine conducted in two provinces of Costa Rica to investigate the efficacy and population impact of the vaccine in the prevention of cervical cancer precursors. More than 24,000 women between 18 and 25 years of age were invited to participate and pre-screened for eligibility, with recruitment of 7466 women (30% of those pre-screened, 59% of those eligible) who were randomized to receive 3 doses of the HPV vaccine or hepatitis A vaccine as control. A complex protocol of data and specimen collection was applied, including an interview, pelvic exam for sexually active women, blood for serology and cell-mediated immunity, cervical secretions for local immunity and cells for HPV, Chlamydia trachomatis and gonorrhea testing. Eighty percent of the women received three doses, 12.4% two doses and 7.4% one dose. At visits, compliance with data and specimen collection was close to 100%. Baseline characteristics and age-specific prevalence of HPV and cervical neoplasia are reported. Overall prevalence of HPV was high (50%), with 8.3% of women having HPV 16 and 3.2% HPV 18. LSIL was detected in 12.7% of women at baseline and HSIL in 1.9%. Prevalence of Chlamydia was 14.2%. There was very good agreement in HPV detection between clinician-collected and self- collected specimens (89.4% agreement for all types, kappa 0.59). Follow up will continue with yearly or more frequent examinations for at least 4 years for each participant.