Is a COVID-19 (Coronavirus Disease 2019) vaccination every 6 months necessary?

COVID-19 Vaccination Recommendations: Not Every 6 Months for Most People

According to the 2024-2025 Advisory Committee on Immunization Practices (ACIP) recommendations, COVID-19 vaccination every 6 months is not necessary for most individuals. For the general population, a single annual dose of the updated COVID-19 vaccine is recommended. 1

General Population Recommendations

• For persons aged ≥12 years without moderate or severe immunocompromise, only 1 dose of the 2024-2025 COVID-19 vaccine (Moderna, Novavax, or Pfizer-BioNTech) is needed to be up to date 1
• For persons aged 5-11 years without moderate or severe immunocompromise, 1 dose of the 2024-2025 COVID-19 vaccine (Moderna or Pfizer-BioNTech) is recommended 1
• The recommended interval between doses is at least 8 weeks after the last COVID-19 vaccine dose 1
• These recommendations apply regardless of previous vaccination history (except for those who have never received any COVID-19 vaccine and choose Novavax, who need 2 doses) 1

Special Populations

• Immunocompromised individuals: May require additional doses beyond the annual recommendation 1

  • Persons who are moderately or severely immunocompromised who have completed an initial series and received at least 1 dose of a 2024-2025 COVID-19 vaccine may receive 1 additional dose at least 2 months after the last recommended dose 1
  • Further additional doses may be administered based on clinical considerations 1

• Adults aged ≥65 years: May benefit from an additional dose during the same season 2

  • ACIP recommended in February 2024 that all persons aged ≥65 years receive 1 additional dose of the updated COVID-19 vaccine due to their increased risk for severe COVID-19 outcomes 2

Safety Considerations

• Safety monitoring of additional COVID-19 vaccine doses has shown no unexpected patterns of adverse reactions 3, 4
• Most adverse reactions after additional doses are mild to moderate 3
• Local and systemic reactions after additional doses are generally similar to or less frequent than those reported after earlier doses 3, 4, 5

Evidence for Efficacy of Additional Doses

• Among adults aged ≥80 years, those receiving booster doses had 75% lower risk of SARS-CoV-2 infection, 82-83% lower risk of COVID-19 hospitalization and ICU admission, and 81% lower risk of death compared to those who completed the primary vaccination series ≥5 months earlier 6
• Booster doses provided 63-87% greater protection against these outcomes compared to those who recently completed a primary vaccination series (<5 months) 6

Common Pitfalls to Avoid

• Assuming that more frequent vaccination (every 6 months) is always better - current evidence supports annual vaccination for most people 1
• Failing to recognize that certain populations (immunocompromised individuals, adults ≥65 years) may benefit from additional doses beyond the annual recommendation 1, 2
• Neglecting to consider the updated strain composition of current vaccines, which are formulated to protect against circulating variants 7

Algorithmic Approach to COVID-19 Vaccination

1. Determine patient's age and immunocompromise status
2. For general population (not immunocompromised):
   • Recommend 1 dose of 2024-2025 COVID-19 vaccine annually
3. For immunocompromised individuals:
   • Complete initial series if not already done
   • Administer at least 1 dose of 2024-2025 COVID-19 vaccine
   • Consider additional dose 2 months after first 2024-2025 dose
4. For adults aged ≥65 years:
   • Consider 1 additional dose of 2024-2025 COVID-19 vaccine
5. For all patients, ensure minimum interval of 8 weeks from previous dose