In a healthy 11‑year‑old or 13‑year‑old requiring human papillomavirus (HPV) vaccination, which WHO‑ and FDA‑approved HPV vaccines—Cervavac (quadrivalent HPV vaccine), Gardasil 9 (nonavalent HPV vaccine), or Cervarix (bivalent HPV vaccine)—are appropriate and what is the recommended dosing schedule?

HPV Vaccine Options and Dosing for 11- and 13-Year-Olds

For healthy 11- or 13-year-old adolescents requiring HPV vaccination, administer Gardasil 9 (9-valent HPV vaccine) using a 2-dose schedule with the second dose given 6–12 months after the first dose. 1, 2

Available HPV Vaccines in the United States

As of January 2017, Gardasil 9 is the only HPV vaccine available in the United States, making it the de facto choice for all adolescents requiring vaccination. 1 The other vaccines mentioned in your question—Cervavac (quadrivalent) and Cervarix (bivalent)—are either not FDA-approved or no longer marketed in the U.S., though they remain WHO-approved and used internationally. 3, 4

Gardasil 9 Coverage and Benefits

• Protects against 9 HPV types: 6,11,16,18,31,33,45,52, and 58. 1, 5
• Prevents approximately 28,500–31,200 cancers annually in the United States, including virtually all cervical cancers, ~90% of anal cancers, ~70% of oropharyngeal cancers, and 60–70% of vaginal, vulvar, and penile cancers. 1
• Prevents ~90% of genital warts caused by HPV types 6 and 11. 1, 3
• Provides 14% additional protection against anogenital cancers and up to 30% additional protection against high-risk precancerous cervical lesions compared to the older quadrivalent vaccine. 1

Recommended Dosing Schedule for Ages 11–13

Two-Dose Schedule (Standard for This Age Group)

Both 11- and 13-year-olds qualify for the simplified 2-dose schedule because they are initiating vaccination before their 15th birthday. 1, 2

• Dose 1: Administer at age 11–12 years (routine) or at age 13 (catch-up). 1
• Dose 2: Give 6–12 months after the first dose. 1, 2
• Minimum acceptable interval: 12 weeks (approximately 3 months) between doses, though longer intervals produce stronger immune responses. 1, 2

Scientific Rationale for Two Doses in Younger Adolescents

• Younger adolescents (ages 9–14) mount significantly higher antibody responses than older individuals receiving 3 doses, which is why the 2-dose schedule is both safe and effective in this age group. 1
• Longer intervals between doses enhance immunogenicity: A 12-month interval generates more robust antibody responses than a 6-month interval, which in turn is superior to a 2-month interval. 1

Administration Details

• Route and site: 0.5 mL intramuscular injection into the deltoid muscle. 1
• Co-administration: HPV vaccine can be given at the same visit as other age-appropriate vaccines (e.g., Tdap, MCV4) using separate syringes at different anatomic sites. 6, 1
• Syncope precaution: Have the patient sit or lie down for 15 minutes after vaccination, as syncope can occur in adolescents following injections. 1, 2

Critical Timing Considerations

Vaccinate before sexual debut to maximize effectiveness. 1, 7

• Approximately 24% of adolescents report sexual intercourse by 9th grade and 58% by 12th grade. 1
• Nearly 60% of males acquire HPV infection within 2 years after sexual initiation. 1
• Do not delay vaccination waiting for "optimal" timing—complete the series promptly to ensure protection before potential HPV exposure. 1, 2

Important Clinical Considerations

No Pre-Vaccination Testing Required

• No Pap testing, HPV DNA testing, or HPV antibody testing is needed before administering the vaccine at any age. 6, 1, 7

Prior HPV Exposure Is Not a Contraindication

• Even if an adolescent is already sexually active or has a history of genital warts or abnormal Pap tests, they should still be vaccinated according to age-based recommendations. 1, 7
• The vaccine protects against HPV types not yet acquired, and most sexually active individuals have been exposed to some but not all vaccine types. 7

Cervical Cancer Screening Still Required

• Vaccination does not eliminate the need for cervical cancer screening in the future, as the vaccine does not protect against all oncogenic HPV types. 1, 7

Special Populations Requiring Three Doses

Immunocompromised adolescents require a 3-dose schedule (0,1–2,6 months) regardless of age at initiation. 1 This includes:

• HIV-positive individuals 6, 1
• Solid organ transplant recipients 1
• Those on immunosuppressive medications 1

Managing Interrupted Schedules

• Never restart the series if interrupted—continue from where you left off. 1, 2
• If only the second dose is delayed, administer it as soon as possible without any upper time limit. 1
• The critical determining factor is the age when the first dose was given, not when subsequent doses are administered. 1

Common Pitfalls to Avoid

• Do not require three doses for a 13-year-old who initiates vaccination before their 15th birthday—two doses are sufficient. 1, 2
• Do not delay vaccination for pre-testing or to "wait for the right time"—early vaccination is most effective. 1, 2
• Do not withhold vaccination from sexually active adolescents—they still benefit from protection against HPV types not yet acquired. 1, 7