International Agency for Research on Cancer

About: International Agency for Research on Cancer is a government organization based out in Lyon, France. It is known for research contribution in the topics: Population & Cancer. The organization has 2989 authors who have published 9010 publications receiving 929752 citations. The organization is also known as: IARC.

Immunogenicity and HPV infection after one, two, and three doses of quadrivalent HPV vaccine in girls in India: a multicentre prospective cohort study

Abstract: Summary Background An increase in worldwide HPV vaccination could be facilitated if fewer than three doses of vaccine are as effective as three doses. We originally aimed to compare the immunogenicity and frequency of persistent infection and cervical precancerous lesions caused by vaccine-targeted HPV after vaccination with two doses of quadrivalent vaccine on days 1 and 180 or later, with three doses on days 1, 60, and 180 or later, in a cluster-randomised trial. Suspension of the recruitment and vaccination due to events unrelated to our study meant that some enrolled girls could not be vaccinated and some vaccinated girls received fewer than the planned number of vaccinations by default. As a result, we re-analysed our data as an observational cohort study. Methods Our study was designed to be done in nine locations (188 clusters) in India. Participants were unmarried girls aged 10–18 years vaccinated in four cohorts: girls who received three doses of vaccine on days 1, 60, and 180 or later, two doses on days 1 and 180 or later, two doses on days 1 and 60 by default, and one dose by default. The primary outcomes were immunogenicity in terms of L1 genotype-specific binding antibody titres, neutralising antibody titres, and antibody avidity after vaccination for the vaccine-targeted HPV types 16, 18, 6, and 11 and incident and persistent infections with these HPVs. Analysis was per actual number of vaccine doses received. This study is registered with ISRCTN, number ISRCTN98283094; and with ClinicalTrials.gov, number NCT00923702. Findings Vaccination of eligible girls was initiated on Sept 1, 2009, and continued until April 8, 2010. Of 21 258 eligible girls identified at 188 clusters, 17 729 girls were recruited from 178 clusters before suspension. 4348 (25%) girls received three doses, 4979 (28%) received two doses on days 1 and 180 or later, 3452 (19%) received two doses at days 1 and 60, and 4950 (28%) received one dose. Immune response in the two-dose HPV vaccine group was non-inferior to the three-dose group (median fluorescence intensity ratio for HPV 16 1·12 [95% CI 1·02–1·23] and for HPV 18 1·04 [0·92–1·19]) at 7 months, but was inferior in the two-dose default (0·33 [0·29–0·38] for HPV 16 and 0·51 [0·43–0·59] for HPV 18) and one-dose default (0·09 [0·08–0·11] for HPV 16 and 0·12 [0·10–0·14] for HPV 18) groups at 18 months. The geometric mean avidity indices after fewer than three doses by design or default were non-inferior to those after three doses of vaccine. Fewer than three doses by design and default induced detectable concentrations of neutralising antibodies to all four vaccine-targeted HPV types, but at much lower concentration after one dose. Cervical samples from 2649 participants were tested and the frequency of incident HPV 16, 18, 6, and 11 infections was similar irrespective of the number of vaccine doses received. The testing of at least two samples from 838 participants showed that there was no persistent HPV 16 or 18 infections in any study group at a median follow-up of 4·7 years (IQR 4·2–5·1). Interpretation Despite the limitations imposed by the suspension of the HPV vaccination, our findings lend support to the WHO recommendation of two doses, at least 6 months apart, for routine vaccination of young girls. The short-term protection afforded by one dose of HPV vaccine against persistent infection with HPV 16, 18, 6, and 11 is similar to that afforded by two or three doses of vaccine and merits further assessment. Funding Bill & Melinda Gates Foundation.

Sexual behavior, condom use, and human papillomavirus: Pooled analysis of the IARC human papillomavirus prevalence surveys

Abstract: Human papillomavirus (HPV) is a sexually transmitted infection but it is unclear whether differences in transmission efficacy exist between individual HPV types. Information on sexual behavior was collected from 11 areas in four continents among population-based, age-stratified random samples of women of ages > or = 15 years. HPV testing was done using PCR-based enzyme immunoassay. Unconditional logistic regression was used to estimate odds ratios (OR) of being HPV positive and corresponding 95% confidence intervals (95% CI). Variables were analyzed categorically. When more than two groups were compared, floating confidence intervals were estimated by treating ORs as floating absolute risks. A total of 11,337 women (mean age, 41.9 years) were available. We confirmed that lifetime number of sexual partners is associated with HPV positivity (OR for > or = 2 versus 1, 1.86; 95% CI, 1.63-2.11) but the association was not a linear one for HPV18, 31, and 33 (i.e., no clear increase for > or = 3 versus 2 sexual partners). Women who had multiple-type infection and high-risk HPV type infection reported a statistically nonsignificant higher number of sexual partners than women who had single-type and low-risk type infections, respectively. Early age at sexual debut was not significantly related to HPV positivity. Husband's extramarital sexual relationships were associated with an OR of 1.45 (95% CI, 1.24-1.70) for HPV positivity in their wives after adjustment for age and lifetime number of women's sexual partners. We did not observe a significant association with condom use. Our study showed an effect of both women's and their husbands' sexual behavior on HPV positivity. Furthermore, it suggests some differences in the pattern of the association between sexual behavior and different HPV types.

Validation and calibration of dietary intake measurements in the EPIC project: methodological considerations. European Prospective Investigation into Cancer and Nutrition.

Abstract: The statistical power of prospective studies on diet in relation to chronic disease risk can be improved by maximizing the variation in true intake levels actually distinguished--or 'predicted'--by dietary questionnaire assessments collected at baseline. This can be achieved by 1) developing a questionnaire method that provides measurements with the smallest possible random errors, thus maximizing the correlation of measured with true habitual intake levels; and 2) increasing the between-person variation in true dietary intake levels when combining multiple cohorts in populations with diverse consumption patterns. The first approach implies that, during the development or selection of the questionnaire method, correlations between measurements and true intake levels can be monitored; the second approach requires adjustment for between-centre differences in over--or underestimation of dietary questionnaire measurements. Besides optimizing the statistical power, it is important that the magnitude of the predicted variation in true intake level is estimated accurately, so as to allow unbiased estimations of relative risks. To meet these various objectives, substudies must be conducted for the 'validation' or 'calibration' of dietary questionnaire assessments, by comparison with additional measurements that have independent sources of error. This paper reviews the methodological considerations underlying the design and implementation of such substudies in the EPIC project, a collaborative multicentre study in nine Western European countries.