How many doses of PCV20 (20‑valent pneumococcal conjugate vaccine, Prevnar 20) are required for pediatric patients, including the routine schedule for healthy infants, recommendations for children with risk conditions, and catch‑up dosing?

PCV20 Dosing for Pediatric Patients

Healthy infants require a 4-dose series of PCV20 at 2,4,6, and 12-15 months of age, with catch-up schedules varying by age at initiation and prior vaccination history. 1

Routine Infant Schedule (Starting at 2 Months)

For infants beginning vaccination at the recommended age:

• Administer 4 doses total: at 2,4,6, and 12-15 months of age 1
• The first dose may be given as early as 6 weeks of age 1
• The fourth dose must be given at least 2 months after the third dose 1
• This schedule mirrors the established PCV13 regimen and has demonstrated robust immune responses in phase 3 trials 2, 3

Key timing rule: Maintain approximately 8-week intervals between the first three doses, with a minimum acceptable interval of 4 weeks 4. The booster dose at 12-15 months must be separated from dose 3 by at least 8 weeks 4.

Catch-Up Schedule for Previously Unvaccinated Children

Ages 7-11 Months

• 3 doses total: Two primary doses at least 4 weeks apart, followed by a third dose after the first birthday, separated from the second dose by at least 2 months 1

Ages 12-23 Months

• 2 doses total: Administered at least 2 months apart 1

Ages 24 Months Through 17 Years

• 1 dose only 1

This age-stratified approach reflects the declining incidence of invasive pneumococcal disease after age 2 years and the improved immune response in older children 4.

Children Previously Vaccinated with Lower-Valency PCV

For children 15 months through 17 years who received one or more doses of PCV13 or PCV7:

• Administer a single dose of PCV20 1
• Wait at least 8 weeks after the last dose of the lower-valency vaccine 1
• This single dose provides coverage for the 7 additional serotypes (8, 10A, 11A, 12F, 15B, 22F, 33F) not included in PCV13 5, 6

Special Populations

Premature Infants

• Use chronologic age (not corrected gestational age) for scheduling 4, 7
• Administer the standard 4-dose series if the infant is medically stable 4, 7

Children with High-Risk Conditions

While the provided evidence focuses on PCV13 rather than PCV20 for high-risk children, the principle remains relevant:

• Children aged 24-71 months with immunocompromising conditions, chronic heart/lung disease, cochlear implants, or CSF leaks historically required 2 doses of PCV13 when starting late 4
• Apply the same catch-up schedule as healthy children for PCV20, as the FDA label does not differentiate dosing by risk status in the pediatric population 1

Critical Implementation Points

Do not restart the series if doses are delayed—simply continue from where vaccination was interrupted 4, 7. Interruption does not require additional doses 4.

PCV20 can be co-administered with other routine pediatric vaccines at separate injection sites 7, 3. In phase 3 trials, 91.7% of participants received all 4 doses when PCV20 was given alongside standard immunizations 3.

Safety profile: Local reactions (pain, redness, swelling) occur in 25-42% of recipients, and systemic events (irritability, fever) in 55-68%, with most being mild to moderate 3. No serious adverse events have been causally linked to PCV20 in pediatric trials 8, 2, 3.

Common Pitfalls to Avoid

• Do not use PPSV23 in children under 2 years—it is only indicated for children ≥2 years with specific high-risk conditions 9, 7
• Do not give doses closer than the minimum intervals: 4 weeks for infants <12 months, 8 weeks for children ≥12 months 4
• Do not delay catch-up vaccination—children who missed earlier doses should start immediately with the age-appropriate schedule 7