HPV vaccination programmes targeting adolescent girls have led to a dramatic reduction in the number of HPV infections, anogenital warts and precancerous cervical lesions (CIN2+) for the age groups targeted by the programme, a meta-analysis* of real-world studies published in The Lancet shows.
The HPV vaccine has been available to 12 to 13-year-old girls since September 2008 in the UK, and during the first two years a catch-up programme was run which offered the vaccine to girls aged up to 18 years through schools and GP surgeries.
The meta-analysis pooled data on 60 million people followed up for up to nine years taken from 65 studies in 14 high-income countries and found rates of the five HPV infections responsible for up to 90% of cancer diagnoses had been cut dramatically in the group targeted. Rates of HPV 16 and 18 infections, the virus responsible for 70% of cervical cancer, decreased by 83% among girls aged 13–19 years, and by 66% among women aged 20–24 years. Meanwhile, prevalence of HPV 31, 33, and 45 infections fell by 54% in 13-19 year old girls.
This translated into fewer HPV-related diseases. Diagnoses of anogenital warts decreased by 67% in girls aged 15–19 years, by 54% in women aged 20–24 years, and by 31% in women aged 25–29 years. Precancerous lesions (CIN2+) also decreased by 51% in screened girls aged 15–19 years and by 31% among women aged 20–24 years.
The researchers said it was too early to see the impact of the vaccination programme on cervical cancer diagnoses.
Groups not targeted by the programme also experienced benefits through herd immunity, the meta-analysis showed, with anogenital wart diagnoses falling by 48% in boys aged 15–19 years and by 32% among men aged 20–24 years.
Mélanie Drolet of the CHU de Quebec-Laval University Research Center, who was one of the researchers, said: “Our results provide strong evidence that HPV vaccination works to prevent cervical cancer in real-world settings as both HPV infections that cause most cervical cancers and precancerous cervical lesions are decreasing. We saw that programmes with multiple age cohorts of girls vaccinated and high vaccination coverage have greater direct impact and herd effects. This finding reinforces WHO’s recently revised position on HPV vaccination to recommend HPV vaccination of multiple age cohorts of girls aged 9–14 years old when the vaccine is introduced in a country, rather than vaccination of a single cohort.”
*Drolet M, Bénard E, Pérez N, et al. Population-level impact and herd effects following the introduction of human papillomavirus vaccination programmes: updated systematic review and meta-analysis. The Lancet, published: June 26, 2019. DOI:10.1016/S0140-6736(19)30298-3