What are the recommended human papillomavirus (HPV) vaccination schedules for healthy young women, including age‑specific dosing and guidelines for immunocompromised patients?

HPV Vaccination Schedule for Young Women

Routine Vaccination Age and Dosing

Initiate HPV vaccination at age 11–12 years for all young women, with the number of doses determined by age at first vaccination: 2 doses for those starting before age 15, and 3 doses for those starting at age 15 or older. 1

Two-Dose Schedule (Ages 9–14 Years)

• For young women who receive the first dose before their 15th birthday, administer only 2 total doses. 1, 2
• The second dose should be given 6–12 months after the first dose (minimum interval: 12 weeks). 1, 3
• This reduced schedule is supported by robust immunogenicity data showing that younger adolescents mount significantly stronger antibody responses than older individuals receiving 3 doses. 1
• Longer intervals between doses (closer to 12 months) produce stronger immune responses than shorter intervals. 1

Three-Dose Schedule (Age 15+ Years)

• Young women who initiate vaccination at age 15 years or older require 3 doses for adequate protection. 1, 3
• The recommended schedule is: dose 1 at month 0, dose 2 at 1–2 months, and dose 3 at 6 months. 1, 3
• Minimum intervals: 4 weeks between doses 1 and 2; 12 weeks between doses 2 and 3. 4, 1

Catch-Up Vaccination

• All young women through age 26 years who are not adequately vaccinated should receive catch-up vaccination. 1
• The age at first dose—not when subsequent doses are given—determines whether 2 or 3 doses are needed. 1
• If a young woman started vaccination at age 14 but receives the second dose after turning 15, she still only needs 2 total doses. 1

Interrupted Schedules

• If the vaccination series is interrupted, do not restart—simply continue from where you left off. 1, 3
• There is no maximum time interval between doses; the vaccine does not lose effectiveness if doses are delayed. 1
• Administer the next dose as soon as possible while maintaining minimum intervals. 1

Special Populations: Immunocompromised Young Women

• All immunocompromised individuals require a 3-dose schedule regardless of age at initiation. 1, 3
• This includes young women with HIV infection, solid organ transplant recipients, and those on immunosuppressive therapy. 1
• Seroconversion rates are lower in immunocompromised patients (53–68% per HPV type), emphasizing the need for the full 3-dose series. 1

Timing and Sexual Activity Considerations

• Vaccination is most effective when administered before sexual debut, but sexually active young women should still be vaccinated according to age-based recommendations. 1, 5
• Approximately 24% of adolescents report sexual intercourse by 9th grade, underscoring the importance of early vaccination. 1, 5
• Prior HPV exposure, history of genital warts, abnormal Pap tests, or positive HPV DNA tests are NOT contraindications to vaccination. 1
• The vaccine protects against HPV types not yet acquired; most sexually active individuals have not been infected with all vaccine types. 1

Administration Details

• Current U.S. vaccine: Gardasil 9 (9-valent HPV vaccine) is the only HPV vaccine available in the United States as of January 2017. 1, 3
• Dose: 0.5 mL administered intramuscularly, preferably in the deltoid muscle. 4
• Co-administration: HPV vaccine can be given at the same visit as other age-appropriate vaccines (Tdap, MCV4) using separate syringes at different anatomic sites. 1
• Post-vaccination observation: Patients should sit or lie down for 15 minutes after administration due to syncope risk in adolescents. 1

Pre-Vaccination Testing

• No pre-vaccination testing is recommended before HPV vaccination at any age. 1, 3, 5
• Do not perform Pap testing, HPV DNA testing, or HPV antibody testing prior to vaccination. 4, 1

Cervical Cancer Screening

• All vaccinated young women must continue cervical cancer screening according to standard guidelines. 1, 3
• The vaccine does not protect against all oncogenic HPV types, so screening remains essential. 1
• Screening recommendations have not changed for vaccinated individuals. 1

Contraindications and Precautions

• Do not administer to individuals with a history of immediate hypersensitivity to yeast or any vaccine component. 1
• Defer vaccination in those with moderate or severe acute illness. 1
• Pregnancy: If a young woman becomes pregnant during the vaccination series, postpone subsequent doses until after delivery. 1
• Breastfeeding: Young women who are breastfeeding can safely receive the HPV vaccine. 1

Common Pitfalls to Avoid

• Do not delay vaccination waiting for "optimal" timing—early sexual debut is common, and delaying reduces effectiveness. 1, 5
• Do not restart the series if interrupted—simply continue with the next dose maintaining minimum intervals. 1
• Do not withhold vaccination from sexually active young women—they remain at risk for HPV types they haven't acquired. 1
• Do not skip the third dose in immunocompromised patients even if they started before age 15. 1