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Background Vaccines are now available for the prevention of HPV-16/18-related cervical infections and pre-cancers, primarily targeting adolescent girls. Since the risk of HPV exposure potentially persists throughout a woman's sexual life, vaccine-derived immunity should be long-term. The current study, HPV-024 ( NCT00546078 , http://clinicaltrials.gov ), assessed the immune memory in North American women who received three doses of HPV-16/18 AS04-adjuvanted vaccine 7 years earlier in HPV-001 ( NCT00689741 ). Methods Women vaccinated in HPV-001 received a 4th-dose of the HPV-16/18 vaccine (024-4DV group, N = 65). Post 4th-dose immune responses were compared with post 1st-dose immune responses in cross-vaccination controls (024-3DV group, N = 50). Reactogenicity was compared between the 4th-dose and the 1st-dose administration. Results Pre 4th-dose, 100% of subjects in the 024-4DV group remained seropositive for anti-HPV-16/18 antibodies (ELISA). Compared to pre 4th-dose, GMTs for anti-HPV-16 and anti-HPV-18 antibodies were respectively 9.3-fold and 8.7-fold higher at day 7, and 22.7-fold and 17.2-fold higher at month 1. Compared to post 1st-dose, GMTs for anti-HPV-16 and anti-HPV-18 were respectively 80.5-fold and 205.4-fold higher at day 7, and 11.8-fold and 20.5-fold higher at month 1. Furthermore, 68.2% and 77.3% of women had HPV-16/18 specific memory B-cells, respectively, pre 4th-dose, rising to 100% one month post 4th-dose vaccination. The 4th-dose was generally well tolerated. Conclusion A 4th-dose of HPV-16/18 AS04-adjuvanted vaccine triggered a rapid and strong anamnestic response in previously vaccinated women, demonstrating vaccine-induced immune memory.

We report efficacy and immunogenicity of the HPV-16/18 AS04-adjuvanted vaccine up to 7.3 years post-vaccination. The study was conducted in a population (N=433) of women enrolled in Brazilian centres from an initial placebo-controlled study. Women were aged 15-25 years at first vaccination. During the most recent year of follow-up, approximately 7 years after initial vaccination, no cases of infection or cytohistological lesions associated with HPV-16/18 were observed in the vaccinees. Vaccine efficacy (95% confidence interval) up to 7.3 years was 94.5% (82.9, 98.9) for incident infection, 100% (55.7, 100) for 12-month persistent infection and 100% (-129.8, 100) for cervical intraepithelial neoplasia grade 2+. Antibody titres for total IgG and neutralising antibodies remained several folds above natural infection levels and >or=96% of women were seropositive. Vaccine safety was similar to placebo. This is the longest follow-up study for a licensed cervical cancer vaccine.

Prophylactic human papillomavirus (HPV) vaccines have to provide sustained protection. We assessed efficacy, immunogenicity, and safety of the HPV-16/18 AS04-adjuvanted vaccine up to 6.4 years.Women aged 15-25 years, with normal cervical cytology, who were HPV-16/18 seronegative and oncogenic HPV DNA-negative (14 types) at screening participated in a double-blind, randomised, placebo-controlled initial study (n=1113; 560 vaccine group vs 553 placebo group) and follow-up study (n=776; 393 vs 383). 27 sites in three countries participated in the follow-up study. Cervical samples were tested every 6 months for HPV DNA. Management of abnormal cytologies was prespecified, and HPV-16/18 antibody titres were assessed. The primary objective was to assess long-term vaccine efficacy in the prevention of incident cervical infection with HPV 16 or HPV 18, or both. We report the analyses up to 6.4 years of this follow-up study and combined with the initial study. For the primary endpoint, the efficacy analysis was done in the according-to-protocol (ATP) cohort; the analysis of cervical intraepithelial neoplasia grade 2 and above (CIN2+) was done in the total vaccinated cohort (TVC). The study is registered with ClinicalTrials.gov, number NCT00120848.For the combined analysis of the initial and follow-up studies, the ATP efficacy cohort included 465 women in the vaccine group and 454 in the placebo group; the TVC included 560 women in the vaccine group and 553 in the placebo group. Vaccine efficacy against incident infection with HPV 16/18 was 95.3% (95% CI 87.4-98.7) and against 12-month persistent infection was 100% (81.8-100). Vaccine efficacy against CIN2+ was 100% (51.3-100) for lesions associated with HPV-16/18 and 71.9% (20.6-91.9) for lesions independent of HPV DNA. Antibody concentrations by ELISA remained 12-fold or more higher than after natural infection (both antigens). Safety outcomes were similar between groups: during the follow-up study, 30 (8%) participants reported a serious adverse event in the vaccine group versus 37 (10%) in the placebo group. None was judged related or possibly related to vaccination, and no deaths occurred.Our findings show excellent long-term efficacy, high and sustained immunogenicity, and favourable safety of the HPV-16/18 AS04-adjuvanted vaccine up to 6.4 years.GlaxoSmithKline Biologicals (Belgium).

We propose a nonparametric test of independence of two autoregressive time series. The test statistic is based on lagged cross-correlation coefficients computed from autoregression rank scores , and extends the traditional correlogram-based method of Haugh (1976) . It is easily computable, asymptotically distribution-free, and, contrary to its traditional parametric competitor, it does not require any estimation of the unknown autoregression parameters. The test is applied in a study of the relations between outdoor temperature and the daily mortality related to cardio-vascular problems in Brussels, during the period 1980–1989.