“The magnitude of the effect is greater than expected,” study author Dr. Tim Palmer from the University of Edinburgh told Reuters Health by email.
Receiving three doses of the vaccine at the recommended ages of 12 to 13 was associated with “a profound reduction of cervical disease seven years later,” he and his colleagues report in the BMJ.
Rates of CIN were low overall. But compared with unvaccinated women, vaccinated women had:
- An 89 per cent lower rate of CIN Grade 3 or worse (0.59 per cent in unvaccinated women versus 0.06 per cent in the vaccinated group).
- An 88 per cent lower rate of CIN Grade 2 or worse (1.44 per cent versus 0.17 per cent).
- A 79 per cent lower rate of CIN Grade 1 (0.69 per cent versus 0.15 per cent).
Girls who were vaccinated at ages 12-13 got a greater benefit: the vaccine was 86 per cent effective for them, and 51 per cent effective when given at age 17.
“The findings are dramatic and document a considerable reduction in high-Grade cervical disease over time,” Julia Brotherton, medical director