IAC summarizes ACIP meeting of January 27, including COVID-19 vaccine safety update

During its meeting on January 27, the Advisory Committee on Immunization Practices (ACIP) received an overview of AstraZeneca’s COVID-19 vaccine candidate and heard presentations on COVID-19 epidemiology, as well as safety and effectiveness data on the currently available mRNA COVID-19 vaccines. Highlights of the meeting, at which no votes were taken, are found below.
 
COVID-19 Vaccine Safety
Since COVID-19 vaccination began in mid-December, the U.S. government has implemented the most intense and comprehensive vaccine safety monitoring program in history. ACIP received updates on COVID-19 vaccine safety data collected from multiple sources, such as CDC’s V-safe After-Vaccination Health Checker, which includes more than 2 million participants. Overall, the safety profiles are reassuring and consistent with observations from pre-authorization clinical trials.
 
Notably, the first report of rapid cycle analysis (RCA) from the Vaccine Safety Datalink project found no elevations above baseline for any outcome of interest, including heart attack, Bell’s palsy, seizures, encephalitis, myelitis, Guillain-Barré syndrome, myocarditis, narcolepsy, stroke, or pulmonary embolism. Now that more data has been accumulated, anaphylaxis has been observed at rates lower than what were published earlier in the MMWR, namely, a rate of 5 cases per million doses for the Pfizer-BioNTech vaccine and 2.8 per million doses for the Moderna vaccine. Data do not suggest any causes for concern with respect to overall safety or deaths following vaccination in older adult residents of long-term care facilities. ACIP’s COVID-19 Vaccine Safety Technical (VaST) Subgroup will continue to monitor available safety data and provide updates to ACIP on a regular basis.
 
AstraZeneca COVID-19 Vaccine (AZD1222)
Representatives from AstraZeneca (AZ) provided an update on the initial results from the Phase 3 clinical trial of the company’s COVID-19 vaccine (AZD1222), which was developed in conjunction with the University of Oxford. Safety and efficacy information, gathered from the vaccine trials conducted in the United Kingdom, Brazil, and South Africa, was reported in The Lancet. The vaccine has been authorized for use (either emergency use or full approval) in dozens of countries, including the United Kingdom and the European Union.
 
AZD1222 was developed on an adenovirus that circulates among chimpanzees (type 63), to minimize issues with pre-existing immunity to human adenoviruses. AZD1222 was generally well tolerated during the clinical trials. Each 0.5 mL dose is administered intramuscularly. It is supplied in 5 mL preservative-free, non-latex multidose vials which can be stored at 2^o to 8^oC for at least 6 months. Following puncture, the vaccine may be stored for up to 6 hours at room temperature or up to 48 hours at 2^o to 8^oC. No dilution or reconstitution is required.
 
Analysis of pooled data from four globally diverse studies, including one site with a different dosing regimen from the others, indicated 70.4% vaccine efficacy against symptomatic COVID-19. Analysis only of data for the standard dosing regimen being considered in the United States demonstrated 62.1% efficacy against symptomatic disease. Investigation is currently underway to determine efficacy against newly identified variants.
 
ACIP will review AZD1222 data more fully after the vaccine is submitted to the FDA to obtain Emergency Use Authorization.
 
COVID-19 in Children and Teens
Children and teens younger than 18 years of age have lower rates of COVID-19 incidence, hospitalization, and mortality than adults. Just over half of children hospitalized with COVID-19 had an underlying condition, with obesity the one most frequently reported. Almost 1,700 cases of Multisystem Inflammatory Syndrome in Children (MIS-C) have been reported in the U.S., with a disproportionate number of these cases occurring among Black and Hispanic children. COVID-19 vaccine trials in adolescents are underway or planned for several vaccines in use or anticipated for use in the U.S., and studies in younger children are planned in early 2021.
 
COVID-19 Vaccine Implementation
COVID-19 vaccination is underway throughout the country. Vaccine has been shipped to more than 18,000 providers in the U.S., and over 20 million people have been vaccinated. Because ACIP prioritization recommendations were intended to be a framework to support equitable and efficient administration of vaccine while allowing jurisdictional flexibility, populations prioritized for COVID-19 vaccination vary between states. As of January 25, 11 states are reported to be in Phase 1a, 38 states in Phase 1b, and 2 states in Phase 1c, using CDC’s categories. As more people are vaccinated, CDC will evaluate real-world vaccine effectiveness.
 
Next Steps
The session concluded with a review of the COVID-19 Work Group’s interpretation of the data presented at the meeting.
 
The next regular meeting of the ACIP is scheduled for February 24–25. However, an emergency meeting could be called before that time if the FDA authorizes an additional vaccine for emergency use. Janssen anticipates submitting results from its Phase 3 trial to the FDA this week. Future meetings are announced on the ACIP meeting website.