The study of the vaccine against human papillomavirus (HPV) has found a reduction of nearly 90 per cent in the cancer-causing virus since the treatment was brought into Scottish schools a decade ago.
The Universities of Aberdeen and Edinburgh were also involved, as well as NHS Scotland organisations – Health Protection Scotland, the Information Services Division and the Scottish Human Papillomavirus Reference Laboratory.
The study discovered that, compared with unvaccinated women born in 1988, vaccinated women born in 1995 and 1996 showed an 89 per cent reduction in the highest risk level of abnormal cells, known as CIN (cervical intraepithelial neoplasia) 3+. There were reductions of, respectively, 88 per cent and 79 per cent in the other risk levels of CIN 2+ and CIN grade 1.
Younger age at vaccination was associated with increasing vaccine effectiveness, at 86 per cent for CIN 3+ or worse for women vaccinated at age 12-13, compared with 51 per cent for women vaccinated at age 17. Unvaccinated women also showed a reduction in disease, suggesting that interruption of HPV transmission in Scotland has created substantial herd protection.
Cervical cancer is the second most common cancer in women aged under 35 in the UK and caused the deaths of more than 800 women in 2016.
Infection with HPV types 16 and 18 is known to be the cause of at least 80 per cent of cases in Scotland. Recent population-based studies suggest that HPV also plays a part in causing other cancers, particularly head-and-neck, vulvo-vaginal and anal cancers.
Professor Chris Robertson and Dr Kimberley Kavanagh, both of the University of Strathclyde’s Department of Mathematics and Statistics, were the university’s lead researchers in the study, which has been published in the British Medical Journal.
Dr Kavanagh said: “The reductions in pre-cancer through this vaccination have been substantial. Finding, when we analysed the data, that the vaccine was protecting against an additional three types of HPV shows how effective it has been.
“We’re hoping to do follow-up research on people as they return to the cervical screening programme in future years. Cervical cancer is more likely to appear as women get older but this would help us to continue monitoring the impact of the vaccine.”
Glasgow Caledonian University’s Senior Research Fellow Dr Kevin Pollock is also one of the lead researchers in the study.
Dr Pollock, who became a Trustee at Jo’s Cervical Cancer Trust – partly due to a close friend being diagnosed as terminally ill – and is a member of the Scottish HPV Investigator’s Network (SHINe), said the findings show the impact of the vaccine on knocking out cervical pre-cancer has exceeded expectations.
He said: “The conclusion is that the vaccine has exceeded expectation. It is associated with near elimination of both low and high grade cervical disease in young Scottish women eight years after the vaccine programme started. The uptake of the HPV vaccine in Scotland is about 90 per cent.
“The figures are impressive and show a reduction of up to 90 per cent of cervical disease abnormalities – pre-cancerous cells. These data are consistent with the reduced circulation of high-risk HPV infection in Scotland and confirm that the HPV vaccine should significantly reduce cervical cancer in the next few years. Indeed, cervical cancer cases in women aged 20-24 have reduced by 69% since 2012.
“We thought that when we first started the programme, the vaccine would knock out the two types which cause 80 per cent of pre-cancerous conditions but because it knocks out these other three types, it is nearer 90 per cent of cervical pre-cancer in Scotland.
“The main message is that the vaccine works. As long as the high uptake continues, the virus has got nowhere to go and it is being eliminated.
“Our study involved women who went along for their first cervical screen from 2008-2016. We assessed 140,000 women in this study and because we can link status of vaccination to the disease its impact is indisputable.”
The research shows that routine vaccination of girls at age 12-13 with the HPV vaccine has led to a dramatic reduction in cervical pre-cancer and a near elimination of both low- and high- grade cervical disease in young Scottish women.
The uptake of the vaccine in Scotland is about 90 per cent. The study assessed 140,000 women who received their first cervical screen between 2008 and 2016. It showed a reduction of up to 90 per cent in cervical disease abnormalities – pre-cancerous cells.
The data are consistent with the reduced circulation of high-risk HPV infection in Scotland and confirm that the HPV vaccine should significantly reduce cervical cancer in the next few years; cervical cancer cases in women aged 20-24 have already reduced by 69 per cent since 2012.