During the CDC’s Advisory Committee on Immunization Practices (ACIP) meeting held on June 27, 2024, voting members recommended the authorized 2024-2025 COVID-19 vaccines for those 6 months of age and older and reaffirmed the influenza vaccination guidelines. The CDC discussed that the 2023-2024 COVID-19 vaccination has proven effective in protecting against various aspects of the virus, including asymptomatic SARS-CoV-2 infections, COVID-19-related visits to emergency departments and urgent care facilities, and hospitalizations. While showing waning patterns over time, it continues to provide notable protection against illness.
Vaccine Effectiveness (VE)
The 2023-2024 COVID-19 vaccination offered increased protection against asymptomatic SARS-CoV-2 infection, COVID-19-related emergency department/urgent care visits, and hospitalizations compared to not receiving the 2023-2024 dose. Similar to previous COVID-19 vaccine formulations, waning patterns were observed, with the most durable protection appearing to be against critical illness, although statistical power was limited for longer periods post-vaccination.
Ruth Link-Gelles, PhD, MPH, who serves as an epidemiologist in CDC’s Division of Viral Diseases, spoke on the overall VE, “I believe it’s crucial to interpret this as providing additional effectiveness within a population already possessing considerable underlying immunity. This population in the US has experienced at least one, possibly multiple, COVID-19 infections and received several vaccine doses. When we reflect on the early days, most of the population completed the initial vaccine series. Therefore, our focus isn’t on whether the vaccine works in absolute terms compared to a naïve population from 2022. Instead, we’re considering how much additional protection we can offer to a population already possessing a certain level of immunity.”
Effectiveness was consistent across age groups, mirroring previous COVID-19 vaccine formulations. Receiving the 2023-2024 COVID-19 vaccine provided protection against the JN1 variant and other circulating variants, though protection may be lower compared to the XBB sublineage variants.
“For older individuals, pregnant adults, those with underlying conditions, or immunocompromised individuals, a VE of 40% to 50% represents a significant reduction in their risk of severe outcomes such as hospitalization, critical illness, or death. While it doesn’t reach the 99% effectiveness seen early on, this level of protection is sufficient because it builds upon existing immunity.”
Slideshow: Looking at Vaccine Efficacy
COVID-19 Vaccine Safety Surveillance
The Vaccine Safety Datalink (VSD) identified statistical signals for Guillain-Barré syndrome (GBS) and ischemic stroke among recipients of the 2023-2024 COVID-19 vaccines, however, no other new or unexpected safety concerns were reported according to the Vaccine Adverse Event Reporting System (VAERS), V-safe, and VSD. This monitoring helps the CDC and FDA ensure the safety of COVID-19 vaccines by promptly identifying and investigating potential adverse events reported by vaccine recipients.
The committee noted that increased rate ratio of GBS following the Pfizer vaccine among individuals aged 65 and older during the 2023-2024 season raises concerns but requires further investigation to determine if it represents a genuine risk. The FDA plans to release its 2023-2024 COVID-19 vaccine safety surveillance data using commercial health and Medicare claims later this year. This upcoming data is expected to offer more comprehensive information on vaccine safety during this period.
Evidence to Recommendations Framework
The FDA is reviewing several COVID-19 vaccines for authorization across different age groups: Moderna’s vaccine for ages 6 months and older, Novavax’s vaccine for ages 12 and older, and Pfizer-BioNTech’s vaccine for ages 6 months and older. Despite weekly hospitalizations and deaths, the current burden of COVID-19 is lower. Among individuals aged 5-49 years, hospitalization rates were notably lower compared to younger age groups, including children without underlying medical conditions.
Overall, ongoing surveillance and analysis are essential to ensure COVID-19 vaccine safety and efficacy. Monitoring via platforms like the Vaccine Safety Datalink, VAERS, and V-safe is crucial, especially with emerging concerns such as signals for GBS and ischemic stroke. The forthcoming release of FDA safety surveillance data will provide additional insights for future COVID-19 vaccine recommendations across different age groups.
ACIP Recommends Influenza Vaccination Guidelines for 2024-2025 Season
The ACIP also reaffirmed the recommendation for routine annual influenza vaccination of all persons aged 6 months and older who do not have contraindications in the meeting.
The second influenza vaccine vote recommended high-dose inactivated HD-IIV3 and adjuvanted inactivated (allV3) influenza vaccines as acceptable options for influenza vaccination of solid organ transplant (SOT) recipients aged 18 through 64 years who are on immunosuppressive medication regimens, without a preference over other age-appropriate IIV3s or RIV3.
The upcoming flu vaccines will be trivalent, excluding the B/Yamagata strain because of its apparent absence. Safety monitoring of 158 million flu vaccine doses found no new concerns.
SOT recipients are at increased risk because of immunosuppression, making nonlive flu vaccines advisable for this population. The committee discussions focused on recommending high-dose or adjuvanted vaccines for immunocompromised populations, such as SOT recipients.