Using a mathematical model, they showed that vaccinating women by ages 12 through 45 against the cancer-causing human papillomavirus, or HPV, could reduce cases of cervical cancer by 85 per cent for 12-year-olds and up to 55 per cent for 45-year-old women.
It could lower rates by 34 to 67 per cent for 25-year-old women, Warner Huh of the University of Alabama told a meeting in Washington of the American Society for Microbiology and the Infectious Diseases Society of America.
The model assumed 100 per cent vaccination rates, which would be difficult to achieve.
Most cases of cervical cancer are caused by the sexually transmitted human papilloma virus.
Merck and Co’s Gardasil vaccine is designed to protect against HPV types 16 and 18, which are known to cause about 70 per cent of all cases of cervical cancer. It also is designed to protect against HPV strains 6 and 11, which cause genital warts.
Gardasil is approved in the US for use in girls and women ages nine to 26, but Merck is seeking to expand its use to older women. The thinking has been that girls must be vaccinated before they are sexually active, because HPV is so common.
The vaccine does not protect anyone who has already been infected with one of the strains of HPV.
Dr Huh’s calculations included clinical trial data on GlaxoSmithKline's Cervarix vaccine, which is approved for sale in Europe.
He assumed Cervarix gave 95 per cent protection against HPV types 16 and 18, and 27 per cent efficacy against all other high-risk HPV types.
Reuters