Search

Background: Reducing the number of doses in the human papillomavirus (HPV) vaccination regimen from 3 to 2 could increase coverage rates. In this cohort study, we assessed the risk of genital warts (GWs) according to timing and number of doses of quadrivalent HPV vaccine., Methods: From population-based registries, we identified all girls in Denmark born during 1985-1999, for whom information on HPV vaccinations was retrieved. The cohort was followed for GW occurrence during 2006-2012. Incidence rate ratios (IRRs) were calculated by Poisson regression to determine differences in GW rates by number of vaccine doses., Results: Of the 550,690 girls in the cohort, 361 734 had been vaccinated. Of these, 25.9% had been vaccinated twice and 58.8% 3 times. The risk of GWs decreased significantly with each additional dose of vaccine. For girls who received 2 doses, extension of the interval between doses reduced the incidence of GWs. In comparison with a 2-month interval, the incidence of GWs was reduced by 45% (95% confidence interval [CI], 20%-62%), 55% (95% CI, 35%-69%), and 63% (95% CI, 44%-75%), with an interval of 4, 5, and 6 months, respectively. The IRR of 2 vs 3 doses was close to 1, with an interval of about 6 months between the first 2 doses., Conclusions: With the original vaccine schedule, completion of 3 doses seems to be required to obtain full protection against GWs. A 2-dose regimen may be as effective if the dosing interval is extended to around 6 months, although the long-term effectiveness of this regimen is unknown., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: A reduction in the incidence of genital warts (GWs) is one of the first markers of the effectiveness of vaccination against human papillomavirus (HPV) at the population level. The aim of this cohort study was to use individual information on HPV vaccination status to assess the effect on risk of GWs., Methods: Population-based registries were used to identify all girls in the birth cohorts 1989-1999 in Denmark, and information about HPV vaccination was obtained for the period 2006-2012. The cohort was linked to incident cases of GWs, and vaccinated and unvaccinated girls were compared using Cox proportional hazards models., Results: A total of 248 403 girls were vaccinated. The relative risk of GWs among girls who had received at least 1 dose of vaccine compared with unvaccinated girls was 0.12, 0.22, 0.25, and 0.62 for those born in 1995-1996, 1993-1994, 1991-1992, and 1989-1990, respectively (P for trend < .0001). No GWs occurred among vaccinated girls in the youngest birth cohort (1997-1999)., Conclusions: The strong, highly significant reduction in the occurrence of GWs among vaccinated girls indicates an early and marked population effect of the national HPV vaccination program and may forecast a similar effect on cervical precancerous lesions.

Background: We conducted a large national cohort study to examine the risk of cancer among men and women with genital warts (GW)., Methods: By use of the Danish National Patient Register, we identified 16,155 men and 32,933 women who received a diagnosis of GW during 1978-2008. Standardized incidence ratios (SIRs) were computed as estimates of the relative risk of specific cancers or sites., Results: A diagnosis of GW was strongly related to anal (SIR for men, 21.5; SIR for women, 7.8), vulvar (SIR, 14.8), vaginal (SIR, 5.9), cervical (SIR, 1.5), penile (SIR, 8.2), and head and neck cancer (SIR, 2.8), including subsites of head and neck cancer with confirmed HPV association (SIR for men, 3.5; SIR for women, 4.8). The risks remained elevated for >10 years following GW diagnosis. In addition, we found moderately increased SIR estimates for nonmelanoma skin cancer, smoking-related cancers, and Hodgkin and non-Hodgkin lymphoma., Conclusions: Individuals with GW have a long-term increased risk of anogenital cancers and head and neck cancers. The elevated risks of nonmelanoma skin cancers might indicate an association with HPV, while excess risks of other cancers could point to differences in other risk factors between individuals with GW and the general population.