Effectiveness of varying number of doses and timing between doses of quadrivalent HPV vaccine against severe cervical lesions

• Published in: Vaccine 2018-10, Vol.36 (43), p.6373-6378
• Main Authors: Dehlendorff, Christian, Sparén, Pär, Baldur-Felskov, Birgitte, Herweijer, Eva, Arnheim-Dahlström, Lisen, Ploner, Alexander, Uhnoo, Ingrid, Kjaer, Susanne K.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age; Cervical cancer; Cervical dysplasia; Cohort Studies; Denmark - epidemiology; Education; Effectiveness; Emigration; Female; Girls; HPV vaccination; Human papillomavirus; Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18 - administration & dosage; Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18 - therapeutic use; Humans; Immunization; Immunization Schedule; Immunogenicity; Lesions; Medical screening; Medicin och hälsovetenskap; Papillomavirus Infections - prevention & control; Population; Risk; Risk reduction; Secondary schools; Statistical analysis; Studies; Sweden - epidemiology; Uterine Cervical Dysplasia - prevention & control; Uterine Cervical Neoplasms - pathology; Uterine Cervical Neoplasms - prevention & control; Uterine Cervical Neoplasms - virology; Vaccination; Vaccines; Womens health; Young Adult
• ISSN: 0264-410X; 1873-2518; 1873-2518
• DOI: 10.1016/j.vaccine.2018.09.011

•Nationwide data from two countries covering more than 2 million women.•Young women vaccinated with 3 doses have reduced risk of severe cervical lesions.•In young women similar risk after 2 doses with 4 months apart compared to 3 doses. Based on immunogenicity studies, a 2 dose HPV vaccination-schedule was recently recommended for girls younger than 15 years. We aimed to investigate the effectiveness of quadrivalent HPV (qHPV) vaccination against CIN2 or worse (CIN2+), by age at vaccination, number of doses, and to test whether optimal timing of 2 doses of qHPV vaccine can confer the same level of protection as the originally recommended three dose-schedule. A population-based cohort of all women aged 13–30 years, living in Denmark or Sweden during 2006–2013, was followed for qHPV vaccination status and first occurrence of CIN2+. The study cohort comprised 2,253,561 women, of which 33% were vaccinated during follow-up, and 1.7% were diagnosed with CIN2+. Vaccination at ages 13–16 and 17–19 was associated with a reduced risk of CIN2+ after 3 doses (IRR = 0.23, 95% CI 0.11–0.49, and IRR = 0.65, 95% CI 0.41–1.03, respectively), compared to being unvaccinated. After 1 and 2 doses there was a reduced risk, but not statistically significant. Women vaccinated ages 13–16 with 2 doses, where time between first and second dose was 5 months or longer showed no difference in risk compared to 3 doses. Women vaccinated with 3 doses of qHPV showed a reduced risk of CIN2+ if they were vaccinated before age 20, with a further reduced risk if vaccinated before age 17. Vaccination with 2 doses, with the second dose 5 months or longer after the first dose, did not yield an increased risk of CIN2+, compared to 3 doses.