A new cross-sectional study suggests that even one dose of human papillomavirus (HPV) vaccine confers significant protection against infection with cancer-causing HPV subtypes.
The study, published in JAMA Network Open, investigated HPV infection prevalence among women in the United States by number of HPV vaccine doses received (2009 to 2016 data).
The study sample included 1,620 women ( 18 to 26 years) , of whom 1,004 were unvaccinated and 616 received at least one dose of HPV vaccine (106 received one dose, 126 received two doses, and 384 received three doses).
Compared with unvaccinated women (prevalence of 12.5% [95% CI 9.7-15.3%]), infection with HPV type 6, 11, 16, or 18 was significantly less prevalent among women who received one dose (2.4% [95% CI 0-4.9%]), two doses (5.1% [95% CI 0.8-9.5%]), or three doses (3.1% [95% CI 0.9-5.3%]) of HPV vaccine.
There was no significant difference in prevalence for one dose versus two doses or one dose versus three doses. Differences were not statistically significant for cross protection (except for two doses versus unvaccinated and one dose versus two doses) and other high-risk HPV types.
The findings support previous observational studies and post-hoc analyses of HPV vaccine trials that demonstrated comparable effectiveness of one dose versus two or three doses.