Study Comparing Immune Response to 2 versus 3 Doses of the 9-Valent HPV Vaccine in Women Aged 27 to 45

What this Trial Is About

Researchers are studying whether two doses of the 9-valent HPV vaccine given to women aged 27 to 45 produce a similar immune response compared to the standard three-dose series. The vaccine is already approved for this age group with a three-dose schedule, but younger individuals typically receive two doses. This trial aims to see if two doses can provide an immune response that is not inferior to three doses in this adult female population. Participants will be randomly assigned to one of two groups one group will receive two doses of the vaccine at 0 and 6 months, while the other group will receive three doses at 0, 2, and 6 months. After 12 months, women who received two doses will be offered a third dose. Blood samples will be collected four times over the course of 12 months to measure immune response. During the study, women will provide blood samples at the start, 1 month, 7 months, and 12 months after the first vaccine dose. They will also be monitored for antibody responses to multiple HPV types. Participants will receive compensation after each blood draw, and reliable telephone access is required for communication throughout the study. The total participation period lasts about 13 months, including the optional third dose offered at the end for the two-dose group.

Comparing Immune Response of 2 vs 3 HPV Doses (27-45 Years Old)