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Background: The Swedish school-based vaccination programme offers HPV vaccine to girls born ≥1999 in 5-6th grade. In 2012, all counties introduced free-of-charge catch-up vaccination campaigns targeting girls born 1993-1998. Varying vaccine uptake in the catch-up group by December 2012 suggested that some implementation strategies were more successful than others. In order to inform future vaccination campaigns, we assessed the impact of different implementation strategies on the county-level catch-up vaccine uptake., Methods: We conducted an ecological study including all Swedish counties (n = 21), asking regional health offices about the information channels they used and where vaccination of the catch-up target group took place in their counties. The uptake of ≥1 dose by 30 September 2014 was estimated using data from the voluntary national vaccination register. We investigated associations between counties' catch-up vaccine uptake, information channels and vaccination settings by calculating incidence rate ratios (IRR) and 95% confidence intervals (CI), using negative binomial regression models., Results: County level catch-up vaccine uptake varied between 49-84%. All counties offered vaccination through primary health care settings. Apart from this eight (34%) also offered the vaccine in some of their schools, four (19%) in all their schools, and two (10%) in other health care centres. The information channels most frequently used were: information at the national on-line health care consulting web-page (100%), letter/invitations (90%), and advertisement (81%). Counties offering vaccination to girls in all schools and counties offering vaccination in some of their schools, reached higher vaccine uptake compared to counties not offering vaccination in any of their schools (all schools adjusted IRR: 1.3, 95% CI: 1.1-1.5, some schools adjusted IRR: 1.2, 95% CI: 1.1-1.3)., Conclusion: Counties offering HPV vaccination to catch-up groups in schools reached the highest vaccine uptake. No information channel explained differences in county-level vaccine uptake. Our findings suggest that catch-up vaccination outside the national vaccination program can reach a high uptake at the population level if it is implemented primarily with an organized delivery (e.g. in schools).

Background: Concerns have been raised that HPV-vaccination might affect women's cervical screening behavior. We therefore investigated the association between opportunistic HPV-vaccination and attendance after invitation to cervical screening., Methods: A cohort of all women resident in Sweden, born 1977-1987 (N=629,703), and invited to cervical screening, was followed October 2006 - December 2012. Invitations to screening were identified via the National Quality Register for Cervical Cancer Prevention, as was the primary outcome of a registered smear. Vaccination status was obtained from two nationwide health data registers. Hazard ratios (HR) were estimated using Cox regression adjusted for age, education level and income (HRadj). Women were individually followed for up to 6 years, of which the first and second screening rounds were analyzed separately., Results: Screening attendance after three years of follow-up was 86% in vaccinated women (N=4,897) and 75% in unvaccinated women (N=625,804). The crude HR of screening attendance in vaccinated vs. unvaccinated women was 1.31 (95% CI 1.27-1.35) in the first screening round. Adjustment for education and income reduced but did not erase this difference (HRadj=1.09, 95% CI 1.05-1.13). In the second screening round, attendance was likewise higher in HPV-vaccinated women (crude HR=1.26, 95% CI 1.21-1.32; HRadj=1.15, 95% CI 1.10-1.20)., Conclusions: HPV-vaccination is so far associated with equal or higher attendance to cervical screening in Sweden in a cohort of opportunistically vaccinated young women. Most but not all of the difference in attendance was explained by socioeconomic differences between vaccinated and unvaccinated women. HPV vaccine effectiveness studies should consider screening attendance of HPV-vaccinated women when assessing incidence of screen-detected cervical lesions.

In order to impede the increase in pertussis incidence in the adolescent group, a school-leaving booster dose administered at the age of 14 to 16 years will be introduced in Sweden in 2016. Preceding this introduction, an open-label, randomized, multicenter, clinical trial without a control group and with blinded analysis was performed, investigating both safety and immunogenicity. Reported here are the memory B-cell and serological responses detected in a smaller cohort (n = 34) of the 230 subjects recruited to the study. All subjects had received primary vaccination consisting of three doses of diphtheria-tetanus-5-component pertussis (DTaP5) vaccine, at 3, 5, and 12 months of age, and a tetanus-low-dose diphtheria-5-component pertussis (Tdap5) vaccine booster at 5.5 years. In this study, the subjects were randomly assigned and received either a Tdap1 or Tdap5 booster. Of the 230 participants, 34 subjects had samples available for evaluation of IgG-producing memory B-cell responses. Both vaccine groups had significant increases in pertussis toxin-specific serum IgG levels, but only the 1-component group showed significant increases in pertussis toxin-specific memory B cells. The 5-component group had significant increases in filamentous hemagglutinin- and pertactin-specific memory B-cell and serum IgG levels; these were not seen in the 1-component group, as expected. In conclusion, this study shows that a 5th consecutive dose of an acellular pertussis vaccine induces B-cell responses in vaccinated adolescents. (This study has been registered at EudraCT under registration no. 2008-008195-13 and at ClinicalTrials.gov under registration no. NCT00870350.)., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Background: Incidence of condyloma, or genital warts (GW), is the earliest possible disease outcome to measure when assessing the effectiveness of human papillomavirus (HPV) vaccination strategies. Efficacy trials that follow prespecified inclusion and exclusion criteria may not be fully generalizable to real-life HPV vaccination programs, which target a broader segment of the population. We assessed GW incidence after on-demand vaccination with quadrivalent HPV vaccine using individual-level data from the entire Swedish population., Methods: An open cohort of girls and women aged 10 to 44 years living in Sweden between 2006 and 2010 (N > 2.2 million) was linked to multiple population registers to identify incident GW in relation to HPV vaccination. For vaccine effectiveness, incidence rate ratios of GW were estimated using time-to-event analyses with adjustment for attained age and parental education level, stratifying on age at first vaccination., Results: A total of 124 000 girls and women were vaccinated between 2006 and 2010. Girls and women with at least one university-educated parent were 15 times more likely to be vaccinated before age 20 years than girls and women whose parents did not complete high school (relative risk ratio = 15.45, 95% confidence interval [CI] = 14.65 to 16.30). Among those aged older than 20 years, GW rates declined among the unvaccinated, suggesting that HPV vaccines were preferentially used by women at high risk of GW. Vaccination effectiveness was 76% (95% CI = 73% to 79%) among those who received three doses of the vaccine with their first dose before age 20 years. Vaccine effectiveness was highest in girls vaccinated before age 14 years (effectiveness = 93%, 95% CI = 73% to 98%)., Conclusions: Young age at first vaccination is imperative for maximizing quadrivalent HPV vaccine effectiveness.