This randomized phase IV trial compares fractional dose of bivalent HPV vaccine to fractional dose of nonavalent HPV vaccine among men and women aged 27-45 years in Seattle, Washington. Participants will have immune response assessed at baseline, 4 weeks, 6 months, 12 months, and 24 months.

Inclusion Criteria:

• Age 27-45 years at enrollment
• Not intending to receive the HPV vaccine series for the duration of the study participation
• Willing and able to provide written informed consent, undergo clinical evaluation, and adhere to follow-up schedule

Exclusion Criteria:

• Prior immunization with HPV-vaccine (Cervarix, Gardasil-4, Gardasil-9)
• Currently pregnant or breastfeeding
• Immune deficiency or other immune disorder
• HIV infection or continued high risk for HIV; patients at risk for HIV who do not have a negative HIV test in the last 6 months will be excluded
• Cancer or chemotherapy (current, within 6 months, or anticipated in the future) except for fully excised non-melanoma skin cancer)
• Unstable medical condition (e.g., malignant hypertension, poorly controlled diabetes,
• Known allergy to vaccine components
• Prior history of HPV-associated cancer