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Human papillomavirus (HPV) causes cervical, vulvar, and vaginal cancers, precancerous dysplasia, and genital warts. We report data for the longest efficacy evaluation to date of a prophylactic HPV vaccine. In total, 552 women (16 -23 years) were enrolled in a randomised, placebo-controlled study of a quadrivalent HPV 6/11/16/18 L1 virus-like-particle vaccine with vaccination at months 0, 2, and 6. At regular intervals through 3 years, subjects underwent gynaecologic examination, cervicovaginal sampling for HPV DNA, serum anti-HPV testing, and Pap testing, with follow-up biopsy as indicated. A subset of 241 subjects underwent two further years of follow-up. At 5 years post enrolment, the combined incidence of HPV 6/11/16/18-related persistent infection or disease was reduced in vaccine-recipients by 96% (two cases vaccine versus 46 placebo). There were no cases of HPV 6/11/16/18-related precancerous cervical dysplasia or genital warts in vaccine recipients, and six cases in placebo recipients (efficacy ¼ 100%; 95% CI:12 -100%). Through 5 years, vaccine-induced anti-HPV geometric mean titres remained at or above those following natural infection. In conclusion, a prophylactic quadrivalent HPV vaccine was effective through 5 years for prevention of persistent infection and disease caused by HPV 6/11/16/18. This duration supports vaccination of adolescents and young adults, which is expected to greatly reduce the burden of cervical and genital cancers, precancerous dysplasia, and genital warts.

Acquisition and clearance of cervical human papillomavirus (HPV) infection were analyzed among 1425 low-income women attending a maternal and child health program in São Paulo, Brazil. Specimens collected every 4 months were tested by a polymerase chain reaction protocol (MY09/11). In all, 357 subjects were positive at least once. There were 1.3% new infections per month, with 38% cumulative positivity after 18 months. Of 177 positive subjects at enrollment, only 35% remained infected after 12 months. The monthly clearance rate was higher for nononcogenic types (12.2%; 95% confidence interval [CI], 9.6-15.4) than for oncogenic HPV infections (9.5%; 95% CI, 7.5-11.9). Median retention times were 8.1 months (95% CI, 7.8-8.3) for oncogenic types and 4.8 months (95% CI, 3.9-5.6) for nononcogenic HPV infections. The mean infection durations were 8.2 and 13.5 months for nononcogenic and oncogenic types, respectively. Although a woman's age did not affect mean duration for oncogenic types (13-14 months), nononcogenic-type infections lasted longer (10. 2 months) among younger (<35 years old) than in older women (5.6 months).

Summary Background Human papillomaviruses (HPVs) cause genital warts and cancers in men. The natural history of HPV infection in men is largely unknown, and that information is needed to inform prevention strategies. The goal in this study was to estimate incidence and clearance of type-specific genital HPV infection in men, and to assess the associated factors. Methods Men (aged 18–70 years), residing in Brazil, Mexico, and the USA, who were HIV negative and reported no history of cancer were recruited from the general population, universities, and organised health-care systems. They were assessed every 6 months for a median follow-up of 27·5 months (18·0–31·2). Specimens from the coronal sulcus, glans penis, shaft, and scrotum were obtained for the assessment of the status of HPV genotypes. Findings In 1159 men, the incidence of a new genital HPV infection was 38·4 per 1000 person months (95% CI 34·3–43·0). Oncogenic HPV infection was significantly associated with having a high number of lifetime female sexual partners (hazard ratio 2·40, 1·38–4·18, for at least 50 partners vs not more than one partner), and number of male anal-sexual partners (2·57, 1·46–4·49, for at least three male partners vs no recent partners). Median duration of HPV infection was 7·52 months (6·80–8·61) for any HPV and 12·19 months (7·16–18·17) for HPV 16. Clearance of oncogenic HPV infection decreased in men with a high number of lifetime female partners (0·49, 0·31–0·76, for at least 50 female partners vs not more than one partner), and in men in Brazil (0·71, 0·56–0·91) and Mexico (0·73, 0·57–0·94) compared with the USA. Clearance of oncogenic HPV was more rapid with increasing age (1·02, 1·01–1·03). Interpretation The data from this study are useful for the development of realistic cost-effectiveness models for male HPV vaccination internationally. Funding National Cancer Institute.

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