Q&A on the Updated COVID-19 Vaccines
Updated COVID-19 vaccines are being rolled out in the U.S., aimed at targeting the latest, prevalent variants of the disease.
The updated vaccines, from Pfizer/BioNTech and Moderna, are available for those ages 6 months and older. The Food and Drug Administration approved the mRNA vaccines on Sept. 11 for those 12 years of age and up, and the FDA issued an emergency use authorization for children ages 6 months to 11 years old. The next day, the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices voted 13 to 1 to recommend that everyone 6 months and older should get the shots, and the CDC endorsed that recommendation.
The 2023-2024 vaccines, as the FDA and CDC have referred to them, come one year after the rollout of the vaccine makers’ bivalent booster vaccines, the first version of COVID-19 vaccines updated to target circulating variants. With the latest FDA action, the bivalent boosters are no longer FDA-authorized and won’t be available. Novavax, which makes a protein-based COVID-19 vaccine, also has submitted an updated vaccine for FDA review, but the agency hasn’t yet made a decision on that.
The updated shots target the omicron variant that has dominated new cases this year. The release comes as the U.S. has seen an uptick in new hospitalizations due to COVID-19 in recent weeks, though the figures so far — nearly 19,000 new hospital admissions for the week of Sept. 2 — are half the peak numbers for the COVID-19 surge late last year, according to the CDC.
Here we answer common questions about the latest vaccines.
How are these updated shots different from the last one?
All of the Pfizer/BioNTech and Moderna COVID-19 vaccines — the originals, the bivalent boosters and the latest updates — use the same mRNA technology to trigger an immune response to the spike protein of SARS-CoV-2, the virus that causes COVID-19. The spike protein is what the virus uses to enter cells. The mRNA in these vaccines provides instructions for cells to make their own spike proteins, which subsequently generates protective antibodies and T cells in the body.
The difference between the versions of the vaccines is in what type of spike protein they prompt the body to make. The mRNA in the 2023-2024 vaccines instructs cells to make the spike protein of omicron variant XBB.1.5. The variant became a concern at the end of last year, when the CDC projected it made up 40.5% of new COVID-19 cases in the U.S., a figure that rose to nearly 90% by early March.
