At what age does the Human Papillomavirus (HPV) vaccine dosage change from 2 to 3 doses?

HPV Vaccine Dosing Schedule Based on Age

The HPV vaccine requires 2 doses for individuals who start vaccination at ages 9-14 years, and 3 doses for those who start at age 15 years or older.

Age-Based Dosing Schedule

Two-Dose Schedule (9-14 years)

• Recommended for children and adolescents who receive their first dose before their 15th birthday 1
• Dosing schedule: 0,6-12 months (minimum 6-month interval between doses) 2, 1
• This applies to both males and females 2

Three-Dose Schedule (15+ years)

• Required for individuals who receive their first dose at age 15 years or older 1, 3
• Dosing schedule: 0,1-2,6 months 1
• Also recommended for immunocompromised individuals regardless of age 1, 3

Special Considerations

Immunocompromised Individuals

• Always require a 3-dose schedule regardless of age at vaccination initiation 1, 3
• This includes individuals with HIV infection 2

Catch-Up Vaccination

• For individuals aged 13-26 years who haven't been previously vaccinated or haven't completed the series 2
• Males aged 22-26 years may be vaccinated (recommended through age 26 for men who have sex with men) 2
• Dosing schedule depends on age at first dose, not current age 2

Interrupted Schedules

• If the vaccination schedule is interrupted, it does not need to be restarted 1
• For a 2-dose schedule: if the second dose is delayed, administer as soon as possible 1
• For a 3-dose schedule: if interrupted after first dose, give second dose as soon as possible, with at least 12 weeks between second and third doses 2

Scientific Rationale

• Studies show that the immune response with 2 doses in younger individuals (9-14 years) is comparable or superior to the response with 3 doses in older individuals 2
• The stronger immune response in younger individuals is the basis for the 2-dose recommendation for ages 9-14 years 2
• The FDA approved the 2-dose schedule for persons 9-14 years of age in October 2016 2

Common Pitfalls to Avoid

1. Incorrect dose timing: Ensure minimum interval of 6 months between doses in a 2-dose schedule
2. Age confusion: The schedule is determined by age at first dose, not current age
3. Restarting series unnecessarily: If schedule is interrupted, continue where left off
4. Missing special population needs: Remember immunocompromised individuals always need 3 doses

The 2-dose schedule for younger individuals simplifies vaccination efforts while maintaining effectiveness, which may help improve vaccination coverage rates compared to a 3-dose schedule 4.