What are the dosage and administration guidelines for the Pfizer (Comirnaty) COVID-19 vaccine?

Pfizer COVID-19 Vaccine (Comirnaty) Dosage and Administration Guidelines

For the 2024-2025 COVID-19 vaccination season, all persons aged ≥6 months should receive one dose of the updated Pfizer-BioNTech COVID-19 vaccine (KP.2 strain) to maximize protection against severe disease, hospitalization, and death. 1

General Dosing Recommendations for Non-Immunocompromised Persons

Adults and Children ≥5 Years

• Unvaccinated persons aged ≥5 years need only 1 dose of the 2024-2025 Pfizer-BioNTech COVID-19 vaccine to be considered up to date 1
• Previously vaccinated persons (who received ≥1 COVID-19 vaccine dose) need 1 dose of the 2024-2025 Pfizer-BioNTech vaccine, administered at least 8 weeks after their last COVID-19 vaccine dose 1, 2

Children 6 Months to 4 Years

• Unvaccinated children require a 3-dose primary series of Pfizer-BioNTech vaccine (administered at 0,3-8 weeks, and ≥8 weeks after dose 2) 1
• Children who previously received 1 dose of Pfizer-BioNTech need 2 additional doses (3-8 weeks between dose 1 and 2, ≥8 weeks between dose 2 and 3) 1
• Children who previously received 2 doses of Pfizer-BioNTech need 1 additional dose of the 2024-2025 vaccine, administered ≥8 weeks after the last dose 1
• Children who previously received ≥3 doses of Pfizer-BioNTech need 1 dose of the 2024-2025 vaccine, administered ≥8 weeks after the last dose 1

Special Considerations for Immunocompromised Persons

Adults and Children ≥12 Years (Moderately or Severely Immunocompromised)

• Unvaccinated persons should complete an initial 3-dose series of the 2024-2025 Pfizer-BioNTech vaccine 1
• Previously vaccinated persons who have completed an initial series need at least 1 dose of the 2024-2025 vaccine 1
• May receive 1 additional dose of the 2024-2025 vaccine at least 2 months after the first 2024-2025 dose if clinically indicated 1

Children 6 Months to 11 Years (Moderately or Severely Immunocompromised)

• Unvaccinated children should receive a 3-dose series of the 2024-2025 Pfizer-BioNTech vaccine 1
• Previously vaccinated children need at least 1 dose of the 2024-2025 vaccine 1

Administration Details

• Pfizer-BioNTech COVID-19 vaccine is administered intramuscularly 3
• Dosage varies by age:
  • Ages 12 years and older: 30 μg (0.3 mL) per dose 3
  • Ages 5-11 years: 10 μg (0.2 mL) per dose 4, 5
  • Ages 6 months-4 years: pediatric formulation with appropriate dosing 1

Timing Considerations

• Standard interval between first and second doses (when applicable) is 3-8 weeks 1
• Minimum interval between any previous COVID-19 vaccine dose and the 2024-2025 vaccine is 8 weeks 1, 2
• Persons who recently had a SARS-CoV-2 infection may consider delaying vaccination by 3 months from symptom onset or positive test 1, 2

Clinical Pearls and Pitfalls

• The 2024-2025 Pfizer-BioNTech vaccine is a monovalent formulation targeting the Omicron KP.2 strain, replacing previous bivalent formulations 1, 2
• Vaccine choice does not need to match previous COVID-19 vaccines received - individuals who previously received Moderna or Novavax can receive Pfizer-BioNTech 1, 2
• Common adverse reactions include injection site pain, fatigue, and headache, which are generally mild to moderate and resolve within a few days 6
• The vaccine has demonstrated high efficacy (>90%) against COVID-19 hospitalization in clinical trials and real-world studies 7, 5
• Vaccination remains the most effective strategy to prevent severe COVID-19 outcomes and reduce community transmission 4, 6

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