Cervical cancer is the third most common cancer among women in the United Kingdom under the age of 35 after breast and skin cancer. A decade ago a UK-wide immunisation programme for girls aged 12 and 13 was introduced.
The therapeutic vaccine, called Tipapkinogen Sovacivec (TS), injects a specific protein that triggers an immune system response to attack high-risk HPV types that cause almost all cervical cancer precursors, known as cervical intraepithelial neoplasia (CIN).
High-risk HPV types, however, linger in the cells that line the surfaces of our body, triggering changes that can eventually turn them cancerous.
There was an 88% reduction in CIN grade 2 or worse, and a 79% reduction in CIN grade 1.
The newest version protects against seven high-risk types that account for 90 per cent of cervical cancers (along with two types that cause genital warts).
"But because it knocks out these other three types, it is nearer 90% of cervical pre-cancer in Scotland."
The researchers from the University of Edinburgh also discovered that the vaccine was more effective in younger women.
Unvaccinated women also showed a reduction, suggesting stopping HPV transmission created "herd protection". Most importantly, the rate of growths classified as a cervical intraepithelial neoplasia (CIN) grade 3 also dropped substantially, by almost 90 per cent.
The study enrolled 192 women, diagnosed with precancerous skin growths, randomising 129 to receive the vaccine and 63, placebo.
That's crucial because a CIN3 growth puts women at their greatest risk of someday developing cervical cancer.
Jo's Trust, a cervical cancer charity that reviewed the paper, commented: 'We think (it has) massive implications for the screening programme, vaccine and also impacts on diagnoses in the future. Women who were immunised at age 12 and 13 have no high-grade disease when screened eight years later.
"The findings will need to be considered by cervical cancer prevention programmes worldwide".
'It also feeds into our policy calls for a new IT infrastructure (for the screening programme in England) to record and enable invitations based on whether someone has at the vaccine if intervals can be extended'.
This suggests, according to the researchers, that most cases of rare cervical cancer can be prevented by HPV vaccination.
They said: 'Different modelling approaches have been used to inform optimal scenarios for screening of vaccinated women but have converged on the conclusion that, for some women, two or three screens in a lifetime using HPV testing might be sufficient.