New COVID booster shots? What to know about Pfizer, Moderna’s modified vaccine doses
New, modified versions of Pfizer’s and Moderna’s existing COVID-19 vaccines received a green light from the Food and Drug Administration to be used as booster shots on Wednesday, Aug. 31.
The “updated boosters” are formulated to target two omicron subvariants — BA.4 and BA.5 — that have been spreading in the U.S. this summer, according to an agency news release. These virus strains are predicted to stick around in the fall and winter.
The doses are now FDA-authorized for emergency use.
“The FDA has been planning for the possibility that the composition of the COVID-19 vaccines would need to be modified to address circulating variants,” Dr. Peter Marks, the director of the FDA’s Center for Biologics Evaluation and Research, said in a statement.
“We sought input from our outside experts on the inclusion of an omicron component in COVID-19 boosters to provide better protection against COVID-19,” Marks added.
The omicron BA.5 subvariant made up 88.7% of COVID-19 cases the week ending Aug. 27, Centers for Disease Control and Prevention data estimates show. Meanwhile, BA.4 made up 3.6% of cases.
Here’s what to know about the “bivalent” booster doses.
The COVID-19 vaccines the FDA has authorized or approved to date, excluding the updated boosters, are considered “monovalent” and include “a component from the original strain of SARS-CoV-2,” according to the agency.
Pfizer and Moderna’s new doses contain two key components — the original virus strain and the strain “in common between the BA.4 and BA.5 lineages of the omicron variant,” the FDA says.
The agency’s authorization comes after the FDA’s Vaccines and Related Biological Products Advisory Committee voted in favor of modified shots targeting omicron in June.
“As we head into fall and begin to spend more time indoors, we strongly encourage anyone who is eligible to consider receiving a booster dose with a bivalent COVID-19 vaccine to provide better protection against currently circulating variants,” FDA Commissioner Dr. Robert M. Califf said in a statement.
Who can get the updated boosters?
Individuals 12 and older are eligible to receive a single shot of Pfizer’s new booster doses at least two months after getting vaccinated or receiving a booster of a monovalent vaccine, according to the FDA.
To get Moderna’s updated booster, the same conditions apply for those 18 and older, the FDA says.
“Based on the data supporting each of these authorizations, the bivalent COVID-19 vaccines are expected to provide increased protection against the currently circulating omicron variant,” the agency’s news release says.
It’s possible for those who receive the updated boosters to experience side effects reported from individuals who have gotten vaccinated with the original FDA-authorized or approved shots, according to the FDA.
The FDA says it examined safety and immunogenicity data from a clinical study before authorizing the bivalent shots.
In studying Pfizer’s new booster, 600 adults 55 and older received a single, updated dose of an “investigational” shot at least 4.7 months after receiving their first booster shot, according to the agency. Moderna’s updated dose was studied in 600 individuals 18 and older who received investigational shots at least three months after their first booster.
The investigational shots were made with components of the original virus and omicron BA.1, not BA.5 and BA.4, the FDA says.
Commonly reported side effects among participants from both the Pfizer and Moderna groups included redness and swelling at the site of the shots, fatigue, headache, muscle pain, joint pain, fever, and chills, according to the FDA.
Another side effect reported by those who received the updated Moderna booster included lymph node swelling in the arm that received the shots, the FDA says.
“We have worked closely with the vaccine manufacturers to ensure the development of these updated boosters was done safely and efficiently,” Marks said. “The FDA has extensive experience with strain changes for annual influenza vaccines. We are confident in the evidence supporting these authorizations.”
In the U.S., the CDC reports COVID-19 cases are “leveling off from their rise over the summer” as of Aug. 26.
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