HPV vaccine shown to also protect against oral HPV infection
Women who received a vaccine targeting two types of the human papilloma virus (HPV) that cause 70 percent of cervical cancers had the added benefit of protection against oral HPV infection, which can lead to cancer of the tonsils and throat (oropharyngeal cancer). It has been previously established that the vaccine prevents genital and anal HPV type 16 and 18 infections and related disease in addition to cervical cancer. Prior to this study, the efficacy of the vaccine against oral HPV infections was unknown. Researchers at NCI, in collaboration with researchers from Costa Rica, showed that the vaccine reduced oral infections by more than 90 percent. The results were published July 17, 2013, in PLOS ONE.
This study was part of the NCI Costa Rica Vaccine Trial, a randomized clinical trial designed to evaluate vaccine efficacy against cervical HPV16/18 infection and related disease. In 2004-2005, investigators enrolled 7,466 healthy young women ages 18 to 25 to the trial. The women were assigned to receive either the HPV16/18 vaccine or a control vaccine. Four years after vaccination, study participants provided oral specimens, which allowed researchers to determine whether the vaccine protected against oral HPV infection. The investigators showed that vaccine efficacy against oral HPV16/18 infection was 93 percent (one infection was reported in the HPV vaccine group vs. 15 in the control group). Infections in the oral cavity are less common than in the genital tract, and oral infections only rarely progress to cancer. According to Aimée R. Kreimer, Ph.D., NCI, the senior author on this paper, this vaccine is expected to prevent the majority of oral infections and will therefore likely contribute to a reduction in HPV-associated cancers of the oropharynx.