Worldwide, an increasing number of countries have implemented HPV vaccination programmes or the vaccine is available. Those with cervical screening, continue to provide secondary prevention to gain most health benefit. The early effect of the HPV vaccination on cervical abnormalities from Australia (1) has shown a significant decrease in high-grade cervical abnormalities in younger women. More recent results from the UK on the prevalence of HPV16/18 and CIN3 from surveillance by Health Protection Scotland demonstrate the prevalence of HPV16 and 18 has decreased in women aged 20 from 29.8% to 13.6%. A reduction was also seen in other hrHPV types, HPV 31, 33 and 45, suggesting cross protection of closely related genotypes. A significant reduction in diagnoses of CIN 1 (RR[1] 0.71), CIN 2 (RR 0.5) and CIN 3 (RR 0.45) was observed in women who received three doses of vaccine compared with unvaccinated women.
Such changes in HPV prevalence and HPV related disease in the screening target population, will impact on the screening performance and disease detection and prevention and should inform service providers.
A programme of research incorporating observational studies from linkage of routinely collected clinical data and additional HPV DNA and genotying studies of women attending for cervical screening in Scotland was used to demonstrate the impact of HPV vaccination in the catch-up programme of women aged 14-18 years once they attend for routine cervical screening from age 20 years.
Observational and interventional data from Scotland shows a reduction in the absolute numbers and relative proportions of young women referred to colposcopy from the cohort of women offered HPV immunisation. This has reduced colposcopy referrals and activity with less procedures and treatments performed. The lower incidence of abnormal cytology and CIN is already impacting on the current screening strategies and performance of colposcopy. In countries with vaccination and screening programmes, screening programmes need to review their criteria for identification of an appropriately high risk group who would benefit from colposcopy and avoid potential harm from screening and interventions in low risk women.