A Second 2024–2025 COVID-19 Vaccine Dose for Adults 65+ and Immunocompromised People

The recommendations

The Advisory Committee on Immunization Practices (ACIP) had recommended 2024–2025 COVID-19 vaccination for everyone aged 6 months and older on June 27, 2024. On October 23, 2024, it voted (15 to zero each time) to add:

• An unvaccinated adult 65 or older receiving Novavax gets 2 doses as the first series, then a third dose of any age-appropriate 2024–2025 vaccine 6 months later (minimum 2 months).
• For immunocompromised people, one of the two recommended doses can be part of the initial series; the other follows 6 months after that series.
• Moderate or severe immunocompromise includes, among others, active cancer treatment, blood cancers linked to poor vaccine response, organ or islet transplants with immune-suppressing therapy, chimeric antigen receptor T-cell therapy, a hematopoietic cell transplant within 2 years, moderate or severe primary immunodeficiency, advanced or untreated HIV, and certain immunosuppressive drugs (full list).

Why these groups

COVID-19 still causes hundreds of deaths and thousands of hospitalizations in the U.S. each week, with peaks in late summer and winter.

• Older adults: 70% of COVID-19 hospitalizations in October 2023–August 2024 were among people 65 and older, and death rates in 2023–2024 were highest at 75 and older, then 65–74. Older adults are less likely to have immunity from infection, and aging immune systems respond less robustly, so they rely more on — and may need more frequent — vaccination.
• Immunocompromised people: about 6% of Americans, but 16% of those hospitalized with COVID-19 in July 2023–May 2024. They may not build strong immunity from infection or vaccines.

The evidence

Protection fades — and a new dose restores it.

• The 2023–2024 vaccine added about 50% protection against hospitalization at first, fading to little or none by about 4–6 months. Against critical illness (intensive care or death), protection started at 67% and was 40% at 4–6 months, with signs of further waning by 6–10 months.
• In people without immunocompromise, effectiveness was 51% at 7–59 days after a dose and 15% at 120–179 days; in people with immunocompromise, 36% and 1%.
• Each additional dose has consistently restored waned protection: after older monovalent vaccines had lost their effect, a bivalent dose raised protection to 51% in immunocompromised people and 52% in others.

Safety. Serious adverse events are rare: anaphylaxis is rarely reported, and the rare risk of myocarditis and pericarditis is mostly in males aged 12–39, with no increased risk seen in adults 65 and older (the risk for immunocompromised people is unknown). Later doses cause fewer reactions than the first series; most are mild, though 10% or more of recipients in 2023–2024 reported effects such as being unable to do daily activities for a time. Older adults reacted less than younger people.

Cost. For adults 65 and older, an extra dose cost $356,534 per quality-adjusted life year saved in the base case — more favorable for people at higher risk of hospitalization, such as those with underlying conditions. No cost data were available for immunocompromised people.

Putting it into practice

• The 6-month interval spreads protection through the year; the 2-month minimum gives flexibility for individual risk and circumstances.
• Shared clinical decision-making lets immunocompromised people time extra doses around immunosuppressive treatment or travel and life events that raise their exposure.
• People can self-attest to being immunocompromised and be vaccinated wherever vaccines are offered — they must not be turned away for lack of documentation.
• The vaccines: Moderna and Pfizer-BioNTech (KP.2 strain) and Novavax (JN.1 strain), approved or authorized by the Food and Drug Administration in August 2024. Detailed schedules are in CDC's clinical considerations.

Report adverse events to the Vaccine Adverse Event Reporting System (1-800-822-7967); providers must report certain events after vaccines given under Emergency Use Authorization.

Sources

Based on Lauren E. Roper, Monica Godfrey, Ruth Link-Gelles and others, "Use of Additional Doses of 2024–2025 COVID-19 Vaccine for Adults Aged ≥65 Years and Persons Aged ≥6 Months with Moderate or Severe Immunocompromise: Recommendations of the Advisory Committee on Immunization Practices — United States, 2024," MMWR, Centers for Disease Control and Prevention; a work of the United States government in the public domain.