Human papillomavirus vaccines provide still some benefit to women who have undergone treatment for HPV-related diseases, according to a new study published in the British Medical Journal.
Dr. Elmar A. Joura, associate professor in the department of gynaecology and obstetrics at the Medical University of Vienna, Comprehensive Cancer Center, in Vienna, Austria, and colleagues conducted a retrospective analysis of data from two international, double blind, placebo-controlled, randomized efficacy trials of quadrivalent HPV vaccine. Joura and colleagues were trying to determine if the administration of quadrivalent HPV vaccine, when compared with placebo, reduced the incidence of subsequent HPV-related disease among women who had undergone surgery for cervical disease or who were diagnosed with vulvar or vaginal disease (i.e., genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia). Participants were women (N=17,622) between 15 years old and 26 years old who had a history of less than 4 sexual partners, no previous abnormal results on a cervical smear test, and were not pregnant. Women were randomly assigned to receive intramuscular injections of quadrivalent HPV vaccine or placebo at day 1, month 2, and month 6.
Joura et al. found that women in the placebo group were more likely to undergo cervical surgery for disease due to any HPV type as compared to their counterparts in the vaccine group (N=763 versus N=587, respectively). Moreover, participants in the placebo group also had higher incidence of any HPV-related disease. Joura and colleagues found a significantly reduced risk of 46.2% of any subsequent HPV-related disease after cervical surgery, irrespective of causal HPV type, associated with the vaccine. They further noted a significant reduced risk of any subsequent cervical disease for cervical intraepithelial neoplasia grade I or worse and any subsequent high grade cervical disease. For participants who received the vaccine, the researchers also found reduced incidence of genital warts and a significantly reduced risk of any subsequent disease related to vaccine HPV type.
“Our study confirms that vaccination does not reduce progression to disease in women who are infected with HPV at the time of vaccination,” the authors wrote, “but women who were treated for disease in the context of these studies were at risk for developing subsequent disease, and vaccination offered substantial benefit.”
Joura et al. added, “Our results of the subgroup analysis demonstrate that vaccination with the quadrivalent HPV vaccine was associated with reduced incidence of subsequent cervical, vulvar, and vaginal intraepithelial neoplasia and genital warts in women who had been diagnosed and treated for cervical and vulvar or vaginal disease.”