A COMUNITY-RANDOMISED PHASE IV HUMAN PAPILLOMAVIRUS (HPV) VACCINATION TRIAL OF VACCINATION STRATEGY

High-risk human papillomavirus (hrHPV) is the 2nd leading cause of cancer in women Bivalent Cervarix™ vaccine is highly efficacious against hrHPVs and associated precancers. Mathematical models disagree about the best vaccination strategy. Thus, we established a community randomised phase IV trial (CRT) to assess effectiveness of different vaccination strategies. During two school years (2007-8 and 2008-9) 80 000 1992-1995 born boys and girls were invited to participate in a CRT in a total of 33 communities in Finland. In 11 arm A communities 90% of girls and boys received HPV16/18 vaccine, in 11 arm B communities 90% of girls received HPV16/18 vaccine and boys received hepatitis B-virus (HBV) vaccine, and in 11 arm C communities both girls and boys received HBV vaccine. Effectiveness of the vaccination strategies in terms of reduction of hrHPV rates was assessed in vaccinated and unvaccinated 18.5 year-old girls. Recruitment resulted in equal enrolment of four birth cohorts (born 1992-95) comprising altogether 32 176 (approximately 40% response) adolescents, including 22 514 girls (> 50% response per birth cohort and arm) and 11 651 boys (20-30% response per birth cohort and arm). Already completed follow-up of 3 614 and 3 256 1992 and 1993 born girls at the age of 18.5 years prove that cervical samples from 350 vaccinated and 85 unvaccinated girls by community will be available. Assuming 80%-95% vaccine efficacy and 30%-50% effectiveness we have 80%-90% power to identify differences between vaccination strategies. In conclusion, this phase IV CRT augments decision making how to implement HPV vaccination programmes.