Study Adds to Evidence That HPV Vaccine Helps Guard Against Cervical Cancer
Large population of Australian women were protected to some degree after vaccination, researchers report
By Mary Brophy Marcus
TUESDAY, March 4, 2014 (HealthDay News) -- A new study offers more evidence that the human papillomavirus (HPV) vaccine is a powerful weapon in the fight against cervical cancer.
In a study that examined the vaccine's effectiveness in a large population of Australian women, the University of Queensland researchers claim their finding suggests HPV vaccination is effective when given to a broad swath of individuals.
HPV can lead to precancerous lesions of the cervix, genital warts and cervical cancer, said Dr. Subhakar Mutyala, associate director of Scott & White Cancer Institute at Texas A&M College of Medicine. Mutyala, who was not involved in the study, said clinical trials have shown that HPV vaccination in young women can prevent HPV infection, with a goal of decreasing cervical cancer.
Australia was the first country to create a national vaccine program using public funds, and health officials there began vaccinating women against the virus in 2007.
The study authors collected data from 2007 to 2011, using a population register in Queensland. More than 100,000 women, who ranged in age from 12 to 26, received their first-ever Pap test during that period. Pap tests look for precancerous and cancerous lesions on the cervix.
To learn more about the effectiveness of the vaccine, the researchers divided the women into three groups based on results from their Pap tests: One group tested positive for precancerous and cancerous lesions; one group tested positive for abnormal but not precancerous lesions; and a third "control" group had normal Pap test results.
The authors then examined the effectiveness of the vaccine in "sexually naive" women who had no prior infection, some of whom had received one dose, two doses or three doses of the three-dose HPV vaccine.
The authors reported that three doses provided 46 percent protection against "high-grade" cervical abnormalities, such as precancerous lesions, and 34 percent protection against other cervical abnormalities, such as genital warts, compared to women who had not received the shots.
The researchers also found that two doses of the vaccine provided 21 percent protection against high-grade abnormalities and other cervical abnormalities. One dose of the vaccine did not shield from infection.