FRIDAY, June 28, 2019 (HealthDay News) -- The human papillomavirus (HPV) vaccination program has had a considerable impact, according to a study published online June 26 in The Lancet.
Mélanie Drolet, Ph.D., from the Université Laval in Québec, Canada, and colleagues conducted a systematic review and meta-analysis of the most recent evidence about HPV vaccine effectiveness; 65 articles in 14 high-income countries were included out of the 1,702 identified as potentially eligible. The primary assessment was the relative risk (RR) of HPV-related end points in the prevaccine and postvaccine periods.
The researchers found that the prevalence of HPV 16 and 18 decreased significantly after five to eight years of vaccination among girls aged 13 to 19 years and among women aged 20 to 24 years (RR, 0.17 and 0.34, respectively). Among girls aged 13 to 19 years, the prevalence of HPV 31, 33, and 45 also decreased significantly (RR, 0.46). There were decreases in diagnoses of anogenital warts among girls aged 15 to 19 years and women aged 20 to 24 years and 25 to 29 years (RRs, 0.33, 0.46, and 0.69, respectively) and among boys aged 15 to 19 years and men aged 20 to 24 years (RRs, 0.52 and 0.68). Cervical intraepithelial neoplasia grade 2+ decreased significantly after five to nine years of vaccination in screened girls aged 15 to 19 years (RR, 0.49) and women aged 20 to 24 years (RR, 0.69).
"These results should be considered within the rapidly changing landscape of HPV vaccination, with several countries recently switching to two-dose schedules, gender-neutral vaccination, and the nonavalent vaccine," the authors write.