A new vaccine against the virus that causes cervical cancer can protect women from the disease for up to four and a half years, scientists have claimed.
US researchers from the Dartmouth medical school conducted a follow-up study into a vaccine against the human papillomavirus (HPV), which is the main cause of the second most common cancer in women.
Dr Diane Harper's initial work, published in 2004, found that vaccines against the HPV-16 and HPV-18 types of the virus, which are most closely linked to cervical cancer, can protect women, but it was unclear how effective they would be in the long-term.
Dr Harper's new report, published in medical journal the Lancet today, reveals that 800 women given the vaccine in the original trial were still protected against the virus more than four years later.
The vaccinated women continued to have high levels of antibodies against HPV-16 and HPV-18, despite it being common for vaccines to decrease in efficacy after four years.
"These findings set the stage for the widescale adoption of HPV vaccination for prevention of cervical cancer," the report's authors said.
UK charity Cancer Research estimates that there are 2,800 new cases of cervical cancer diagnosed in the UK every year.