What is the recommended schedule and eligibility for Human Papillomavirus (HPV) vaccination, specifically Gardasil 9 (9-valent HPV vaccine), for adolescents and young adults?

HPV Vaccination: Schedule and Eligibility

Routine HPV vaccination should be initiated at age 11-12 years (can start as early as age 9 years), with catch-up vaccination recommended for all persons through age 26 years who are not adequately vaccinated. 1

Age-Based Vaccination Schedule

Routine Vaccination (Ages 9-14 Years)

• Initiate vaccination at age 11-12 years; vaccination can begin as early as age 9 years. 1
• For individuals starting before their 15th birthday: 2-dose schedule at 0 and 6-12 months. 2
• The 2-dose schedule is based on robust immunogenicity data showing younger adolescents mount stronger antibody responses than older individuals receiving 3 doses. 2
• The minimum acceptable interval between doses is 6 months, though longer intervals (closer to 12 months) may produce stronger immune responses. 2

Adolescents and Young Adults (Ages 15-26 Years)

• For individuals starting at age 15 years or older: 3-dose schedule at 0,1-2, and 6 months. 1, 2
• Minimum intervals: 4 weeks between doses 1 and 2, and 12 weeks between doses 2 and 3, with at least 24 weeks between doses 1 and 3. 2, 3
• Catch-up vaccination is recommended for ALL persons through age 26 years who are not adequately vaccinated. 1

Adults (Ages 27-45 Years)

• Catch-up vaccination is NOT routinely recommended for all adults aged 27-45 years. 1
• Shared clinical decision-making is recommended for some adults aged 27-45 years who are not adequately vaccinated and may be at risk for new HPV infection. 1
• The American Cancer Society explicitly does not endorse routine vaccination for ages 27-45 due to low effectiveness and minimal cancer prevention potential (only 0.5% additional cancer cases prevented). 4
• HPV vaccines are not licensed for use in adults over age 45 years. 1

Critical Dosing Principles

Series Completion Rules

• The age at first dose determines the schedule—NOT the age at subsequent doses. 2
• If vaccination is initiated at age 14 years, only 2 doses are needed (given at least 6 months apart), even if the second dose is administered after age 15. 2
• If the series is interrupted, do NOT restart—continue from where you left off, maintaining minimum intervals. 2, 3

Special Populations Requiring 3 Doses

• Immunocompromised individuals require a 3-dose schedule regardless of age at initiation. 2, 3
• This includes HIV-positive individuals, solid organ transplant recipients, and others with immunocompromising conditions. 2

Vaccine Type and Protection

Gardasil 9 (9-valent HPV vaccine)

• Gardasil 9 is the only HPV vaccine distributed in the United States since late 2016. 1
• Protects against HPV types 6,11,16,18,31,33,45,52, and 58. 1
• Prevents approximately 92% of HPV-attributable cancers (cervical, oropharyngeal, anal, vaginal, vulvar, and penile). 1
• Also prevents 90% of anogenital warts (caused by HPV types 6 and 11). 1

Important Clinical Considerations

No Pre-Vaccination Testing Required

• Do NOT perform Pap testing, HPV testing, or antibody testing before vaccination. 1, 2
• No clinical antibody test can determine whether a person is immune or susceptible to specific HPV types. 4

Prior HPV Exposure or Disease

• History of genital warts, abnormal Pap test, or positive HPV DNA test is NOT a contraindication to vaccination. 4, 3
• Vaccination should proceed regardless of sexual activity history, as individuals are unlikely to have been infected with all vaccine HPV types. 4, 3
• HPV vaccines are prophylactic only—they prevent new infections but do NOT treat existing infections or HPV-related diseases. 4, 3

Pregnancy and Breastfeeding

• Vaccination should be delayed until after pregnancy. 1, 3
• Pregnancy testing is not required before vaccination. 1
• Breastfeeding women can safely receive HPV vaccine. 1, 3

Cervical Cancer Screening

• Cervical cancer screening recommendations remain unchanged for vaccinated individuals. 1, 2, 3
• Vaccines do not protect against all oncogenic HPV types, so screening must continue per guidelines. 2, 3

Co-Administration with Other Vaccines

• HPV vaccine can be administered at the same visit as other age-appropriate vaccines (Tdap, MCV4) using separate syringes at different anatomic sites. 2
• Co-administration increases likelihood of completing all recommended adolescent vaccinations on schedule. 2

Common Pitfalls to Avoid

Do NOT:

• Delay vaccination waiting for "optimal" timing—approximately 24% of adolescents report sexual intercourse by 9th grade. 2
• Restart an interrupted series—this results in unnecessary doses. 2, 3
• Assume prior HPV exposure means no benefit—even sexually active individuals benefit from protection against vaccine types they haven't acquired. 4, 3
• Skip cervical cancer screening in vaccinated women—vaccines don't protect against all oncogenic types. 2, 3

Adverse Events

• Most common adverse effects are local injection-site reactions (pain, redness, swelling) occurring in approximately 60% of recipients—these are mild and self-limited. 3
• Patients should sit or lie down for 15 minutes after vaccination, as syncope can occur in adolescents following injections. 2
• Serious adverse events are rare. 3

Rationale for Early Vaccination

• Vaccination is most effective when given before exposure to HPV through sexual activity. 1, 2, 4
• HPV acquisition generally occurs soon after first sexual activity. 1
• Most new HPV infections occur in adolescents and young adults. 1
• HPV infection incidence is nearly 60% within 2 years after sexual initiation in males. 2