Source: Cleveland Plain Dealer (OH)
By: Townsend, Angela
New research shows that a single dose of the Cervarix vaccine may be sufficient to protect against cervical cancer. Published in Cancer Prevention Research, the study found that just one of the three recommended doses of the human papillomavirus (HPV) vaccine generated antibodies that remained stable in the blood for four years. Researchers are planning to study whether that protection lasts even longer, which could help simplify the vaccine process given that most individuals do not receive all three doses. According to lead researcher Mahboobeh Safaeian of the National Cancer Institute’s Division of Cancer Epidemiology and Genetics, “Vaccination with two doses, or even one dose, could simplify the logistics and reduce the cost of vaccination, which could be especially important in the developing world, where more than 85 percent of cervical cancers occur, and where cervical cancer is one of the most common causes of cancer-related deaths.” Researchers analyzed data from a Phase 3 clinical trial of women in Costa Rica and compared blood samples from 78 women who received one dose, 192 women who received two doses, and 120 women who received three doses with those from 113 women who were not vaccinated but had antibodies against the virus due to a past HPV infection. They found that women in all three dosing groups had antibodies against HPV 16 and 18 for as many as four years, with comparable levels among those receiving two doses six months apart and those receiving all three doses. Even the women who received only one dose had stable antibody levels, and the antibody levels of women who received one or two doses were anywhere from five to 24 times higher than unvaccinated women with antibodies due to a past HPV infection.