What is the recommended three‑dose schedule for the human papillomavirus (HPV) vaccine (Gardasil 9) for patients aged 15 years or older or who are immunocompromised?

HPV Vaccine 3-Dose Series Dosing Schedule

Recommended Schedule

For individuals aged 15 years or older and immunocompromised patients of any age, administer the HPV vaccine (Gardasil 9) on a 3-dose schedule at 0,1-2, and 6 months. 1, 2, 3

Specific Timing Details

• First dose: Administer at the elected date 1
• Second dose: Administer 1-2 months after the first dose 1, 2, 3
• Third dose: Administer 6 months after the first dose 1, 2, 3

Minimum Acceptable Intervals

• Between doses 1 and 2: Minimum of 4 weeks 1, 2, 3
• Between doses 2 and 3: Minimum of 12 weeks 1, 2, 3

These minimum intervals are critical when the standard schedule cannot be followed, but longer intervals are preferred and may produce stronger immune responses. 2, 4

Why Three Doses for Ages 15+?

The immune response to HPV vaccination is age-dependent, with younger individuals mounting stronger antibody responses than older individuals. 1 Studies demonstrate that individuals who start vaccination after age 15 require three doses to achieve adequate protection against HPV infection, whereas those under 15 can achieve similar protection with only two doses. 1, 5

Special Populations Requiring 3-Dose Schedule

Immunocompromised individuals must receive the 3-dose schedule regardless of age at initiation. 1, 2, 5 This includes:

• Patients with HIV infection 1
• Solid organ transplant recipients 2
• Other immunocompromising conditions 2, 5

Seroconversion rates in transplant recipients are notably lower (53-68% per HPV type) compared to immunocompetent individuals, making the full 3-dose series essential. 2

Managing Interrupted Schedules

If the vaccination schedule is interrupted, do not restart the series—simply continue from where you left off. 1, 2, 3 There is no maximum time interval between doses, and the vaccine does not lose effectiveness if doses are delayed. 2 The only requirement is maintaining the minimum intervals of 4 weeks between doses 1 and 2, and 12 weeks between doses 2 and 3. 1, 2

Important Clinical Considerations

• No prevaccination testing is needed to establish appropriateness of HPV vaccination, including no HPV DNA testing, antibody testing, or Pap testing. 1, 2
• Prior HPV exposure is not a contraindication to vaccination—history of genital warts, abnormal Pap tests, or positive HPV DNA tests do not preclude vaccination, as the vaccine will protect against HPV types not yet acquired. 2
• Vaccination is most effective before sexual debut, but sexually active individuals should still be vaccinated according to age-based recommendations. 1, 2
• Cervical cancer screening must continue regardless of vaccination status, as vaccines do not protect against all oncogenic HPV types. 1, 2

Administration Precautions

• Administer via intramuscular injection 2
• Have patients sit or lie down for 15 minutes after vaccination due to syncope risk in adolescents and young adults following injections 2, 3
• HPV vaccine can be co-administered with other age-appropriate vaccines using separate syringes at different anatomic sites 2

Common Pitfall to Avoid

The determining factor for the dosing schedule is the age when the first dose was given, not when subsequent doses are administered. 2 If a patient initiated vaccination at age 14 and receives the second dose after turning 15, they still only need 2 total doses. Conversely, if vaccination was initiated at age 15 or older, 3 doses are required regardless of timing of subsequent doses. 2