A study from Australia is the first to show reduction of high-grade cervical abnormalities (HGAs—the precursors to cervical cancer) in a population of women following introduction of human papillomavirus (HPV) vaccination programmes. However, the authors add that more work is needed to link this lower incidence definitively to vaccination status. The Article in The Lancet is by Dr Julia Brotherton, Victorian Cytology Service Registries, East Melbourne, Victoria, Australia, and colleagues.
Australia introduced an HPV vaccination programme, with the quadrivalent HPV vaccine, for all women aged 12-26 years between 2007 and 2009. In this study, the authors analysed trends in cervical abnormalities (both high-grade and low-grade [LGAs]) in women in Victoria, Australia, before and after introduction of the vaccination programme.
They found that after the introduction of vaccination, the incidence of HGAs in girls aged 17 years and younger fell by 0•38% as compared with before the vaccination programme (from 0•80% to 0•42% among screened women, an almost 50% decline). No decline was seen for LGAs or in older age groups.
The authors say: "Our finding that the decrease in HGA incidence occurred in the youngest vaccination cohort before it occurred in the older, catch-up cohorts (who were more likely to have been previously sexually experienced) reinforces the appropriateness of the targeting of prophylactic HPV vaccines to preadolescent girls."
They add: "Linkage between vaccination and screening registers is needed to confirm that this ecological observation is because of vaccination and to monitor participation in screening."
They conclude: "This is the first report of a decrease in incidence of high-grade cervical abnormalities within 3 years after the implementation of a population-wide HPV vaccination programme."
In a linked Comment, Dr Mona Saraiya and Dr Susan Hariri, Centers for Disease Control and Prevention, Atlanta, GA, USA, say: "The not-so-cautious optimist in us wants to hail this early finding as true evidence of vaccine effect. However, individual-level vaccine status was not considered—as it perhaps should have been in view of the availability of such data in Victoria—and, as stated by Brotherton and colleagues, linkage between vaccination and screening registers is needed to confirm these findings independent of possible bias by screening policy or practice changes. Indeed, more rigorous epidemiological studies are needed—many are under way—to increase our understanding of HPV vaccine effectiveness against cervical disease."
Dr Julia Brotherton, Victorian Cytology Service Registries, East Melbourne, Victoria , Australia. T) +61 3 9250 0377 (Please note Melbourne is GMT +9 hours) E) jbrother@vcs.org.au
For Dr Mona Saraiya, Centers for Disease Control and Prevention, Atlanta, GA, USA, please contact Anita Blankenship, CDC Media Center. T) +1 404 639-3286 E) aob4@cdc.gov
Journal
The Lancet