Cervical cancer rates are 87% lower in women who were offered vaccination against human papillomavirus (HPV) when they were between the ages of 12-13 than in previous generations confirms a new study published in The Lancet.
The researchers also found reductions in cervical cancer rates of 62% in women offered vaccination between the ages of 14-16, and 34% in women aged of 16-18 when vaccination was introduced. This is the first direct evidence of prevention of cervical cancer using the bivalent vaccine, Cervarix.
HPV vaccination has been introduced in 100 countries as part of efforts by the World Health Organization (WHO) to eliminate cervical cancer. England initially used a bivalent vaccine which protects against the two most common types of HPV, responsible for approximately 70-80% of all cervical cancers. The English HPV vaccination programme was introduced in 2008, with vaccines given to women between 12-13 years old and ‘catch-up’ vaccinations offered to older age groups up to the age of 18.
‘Although previous studies have shown the usefulness of HPV vaccination in preventing HPV infection in England, direct evidence on cervical cancer prevention was limited,’ said Professor Peter Sasieni, King’s College London, one of the authors of the paper. ‘Early modelling studies suggested that the impact of the vaccination programme on cervical cancer rates would be substantial in women aged 20-29 by the end of 2019. Our study aims to quantify this early impact. The observed impact is even greater than the models predicted.’
During the study period, 28,000 diagnoses of cervical cancer and 300,000 diagnoses of CIN3 were recorded in England. In the three vaccinated cohorts there were around 450 fewer cases of cervical cancers and 17,200 fewer cases of CIN3 than expected in a non-vaccinated population. The research found reductions in cervical cancer rates of 87% in women targeted between the ages of 12-13, 62% in women vaccinated between the ages of 14-16, and 34% in those eligible for vaccination between the ages of 16-18. The corresponding reductions in CIN3 rates were 97%, 75%, and 39%, respectively.
‘This study provides the first direct evidence of the impact of the UK HPV vaccination campaign on cervical cancer incidence, showing a large reduction in cervical cancer rates in vaccinated cohorts. As expected, vaccination against HPV was most effective in the cohorts vaccinated at ages 12-13 amongst whom the uptake was greatest and prior infection least likely,’ said co-author Dr Kate Soldan from the UK Health Security Agency.
It should also be noted that the bivalent vaccine Cervarix used in the UK from 2008-2012. Since September 2012, the quadrivalent vaccine Gardasil has been used instead.
Filcaro M, et al. The Lancet, published online 3 November 2021 https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02178-4/fulltext
