Study shows ‘real-world impact’ of HPV vaccine on cervical lesions
HPV vaccination programs significantly decrease HPV infections and cervical lesions among girls and women, as well as anogenital wart diagnoses among girls, women, boys and men, according to a systematic review and meta-analysis published in The Lancet.
“Our results provide strong evidence of HPV vaccination working to prevent cervical cancer in real-world settings, as both high-risk HPV infection and precancerous cervical lesions are significantly declining,” study author Marc Brisson, PhD, from Université Laval, Quebec, Canada, told Infectious Diseases in Children. “Our results can be used by clinicians to illustrate the real-world impact of HPV vaccination outside the very controlled settings of randomized trials.”
Brisson and colleagues previously conducted a systematic review and meta-analysis in 2015 that examined the real-world population-level impact of HPV vaccination and found that HPV 16 and HPV 18 infections and anogenital wart diagnoses among women targeted for vaccination decreased substantially 4 years after the introduction of the vaccine. They also found evidence of herd effects among boys and older women. However, 4 years was not a long enough period to study the vaccine’s impact on cervical intraepithelial neoplasia of grade 2 or higher (CIN2+), they said.
The current meta-analysis builds on those findings by including studies published between February 2014 and October 2018 that compared the frequency of at least one HPV-related endpoint — genital HPV infections, anogenital wart diagnoses or histologically confirmed CIN2+ — between pre-vaccination and post-vaccination periods among the general population. The analysis included 65 articles in 14 high-income countries, with about 60 million individuals, they wrote.
After 5 to 8 years of vaccination, the prevalence of HPV 16 and HPV 18 — which cause about 70% of cervical cancer, Brisson noted — decreased by 83% (RR = 0.17; 95% CI, 0.11-0.25) among girls aged 13 to 19 years, and by 66% (RR = 0.34; 95% CI, 0.23-0.49) among women aged 20 to 24 years. The prevalence of HPV 31, 33 and 45 — which are also considered high-risk HPV types — decreased by 54% (RR = 0.46; 05% CI, 0.33-0.66) among girls aged 13 to 19 years.
Anogenital wart diagnoses decreased by 67% (RR = 0.33; 95% CI, 0.24-0.46) among girls aged 15 to 19 years, by 54% (RR = 0.46; 95% CI, 0.36-0.6) among women aged 20 to 24 years and by 31% (RR = 0.69; 95% CI, 0.53-0.89) among women aged 25 to 29 years. They decreased by 48% (RR = 0.52, 95% CI 0.37-0.75) among boys aged 15 to 19 years, and among men aged 20 to 24 years, they decreased by 32% (RR = 0.68; 95% CI, 0.47-0.98).
CIN2+ decreased by 51% (RR = 0.49; 95% CI, 0.42-0.58) after 5 to 9 years of vaccination among girls aged 15 to 19 years, and by 31% (RR = 0.69; 95% CI, 0.57-0.84) among women aged 20 to 24 years.
“We thought it was interesting that the promising HPV vaccine efficacy results from randomized controlled trials were materializing so quickly in real-world settings, and girls-only vaccination was producing substantial herd effects among unvaccinated boys and young men,” Brisson said. – by Joe Gramigna
Disclosures: The authors report no relevant financial disclosures.