NIH study finds two doses of HPV vaccine may be as protective as full course
Two doses of the human papillomavirus (HPV) vaccine Cervarix are as effective as the current standard three-dose regimen after four years of follow-up according to the results of a community-based clinical trial on Cervarix in Costa Rica.
Akinso: Two doses of an HPV vaccine are as effective as the standard treatment according to a National Institutes of Health study.
Kreimer: The vaccine is called Cervarix.
Akinso: Dr. Aimée Kreimer at the NIH is the lead author of the study.
Kreimer: So this vaccine is intended to protect against HPV type 16 and HPV type 18. We intended for women to get the standard regimen which was three doses. But for some women about 20 percent of our population received actually less than three doses and this was typically for involuntary reasons, such as pregnancy.
Akinso: Cervarix is a vaccine approved by the U.S. Food and Drug Administration to protect against persistent infection with two HPV types, 16 and 18, which together account for 70 percent of all cervical cancer cases. The vaccine is intended to be administered in three does given over the course of six months.
Kreimer: And so we were able then to look at the vaccine efficacy against persistent HPV 16 and 18 infections among women who received the standard three dose regimen but also among women who received two doses and women who received a single dose.
Akinso: The trial was based out of Costa Rica. Women ages 18 to 25 years were randomly assigned to receive the HPV vaccine or a Hepatitis A vaccine as the control treatment. Dr. Kreimer explains how researchers came up with their conclusion.
Kreimer: What we observed was that the vaccine efficacy for women who received two doses or even a single dose was quite comparable to that of the standard regimen. This observation was after four years of follow-up.
Akinso: Dr. Kreimer says further studies are needed to confirm the findings in other populations as well as to quantify the duration of protection for fewer than three doses. For more information on this study, visit www.cancer.gov. This is Wally Akinso at the NIH, Bethesda, Maryland.
About This Audio Report
Reporter: Wally Akinso
Sound Bite: Dr. Kreimer
Topic: HPV, Cervarix