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Adolescents and adults can start receiving a bivalent COVID-19 vaccine booster dose designed to protect again the omicron variant.
The Centers for Disease Control and Prevention (CDC) director signed off on the updated boosters from Moderna and Pfizer-BioNTech Thursday after they were recommended in a 13-1 vote by the CDC’s Advisory Committee on Immunization Practices (ACIP).
“The updated COVID-19 boosters are formulated to better protect against the most recently circulating COVID-19 variant,” CDC Director Rochelle P. Walensky, M.D., M.P.H., said in a press release. “They can help restore protection that has waned since previous vaccination and were designed to provide broader protection against newer variants. This recommendation followed a comprehensive scientific evaluation and robust scientific discussion.”
The bivalent vaccine boosters contain both the original strain of SARS-CoV-2 and the omicron BA.4/5 variant. About 89% of circulating strains are BA.5, and nearly all the rest are BA.4, according to the CDC. Officials have been preparing for a possible surge this fall and winter as people spend more time indoors.
The Pfizer-BioNTech bivalent booster can be used for people ages 12 and older, while the Moderna bivalent booster can be used for those ages 18 and older. A bivalent booster can be given as a single dose at least two months after a primary series or booster with any authorized monovalent COVID-19 vaccine.
About 209 million people in the U.S. are eligible for the bivalent boosters, including 14 million adolescents ages 12-17 years, according to the CDC. The government has purchased about 171 million bivalent booster doses.
Safety and immunogenicity
Trials in adults found bivalent boosters with the BA.1 strain from both manufacturers increase the immune response of people who have previously received the primary series and monovalent booster doses. Compared to the original boosters, the bivalent boosters produce a superior immune response to the omicron variant without compromising the response to the original strain.
Reactogenicity after the bivalent boosters was similar to the primary series and original boosters. While the risk of myocarditis after a bivalent booster is unknown, the risk after monovalent boosters is lower than after the second dose of the primary series, according to data from the Vaccine Adverse Events Reporting System.
While more than 1,400 people received a bivalent vaccine with omicron in trials, it did not include the BA.4/5 strain used in the updated vaccines. Several ACIP members expressed concerns about only animal studies being available for BA.4/5, including Pablo J. Sanchez, M.D., FAAP, a neonatologist and pediatric infectious diseases specialist at Nationwide Children’s Hospital in Columbus, Ohio. He cast the lone “no” vote.
“It's a new vaccine, a new platform, there’s a lot of vaccine hesitancy already,” he said. “We need the human data. At the same time, I think the vaccine will have similar safety as we’ve already seen with the previous (mRNA) vaccines.”
ACIP COVID-19 Vaccines Work Group Chair Matthew F. Daley, M.D., FAAP, senior investigator at the Institute for Health Research at Kaiser Permanente Colorado, said he also struggled with the lack of BA.4/5 specific data but pointed to CDC modeling that found giving boosters to adults starting in September could prevent 137,000 more hospitalizations and 9,700 more deaths compared to waiting until November.
“I find it quite reassuring that the immune response in general to the bivalent vaccines really does seem more diverse and I’m hopeful it will protect against additional variants,” he said.
Other members also said they were reassured by more than 600 million doses of Pfizer-BioNTech and Moderna vaccines having been given in the U.S. and robust safety monitoring.
ACIP Executive Secretary Melinda Wharton, M.D., M.P.H., said changing vaccine strains without a clinical trial happens every year with the flu vaccine. The CDC also said differences between the BA.1 strain in the clinical trials and the BA.4/5 strain in the updated booster are subtle. Trials with the BA.4/5 strain are ongoing.
Doran Fink, M.D., M.P.H., deputy director of the Food and Drug Administration’s Division of Vaccines and Related Products Applications, addressed concerns about trials including only adults. While there may be some differences in reactogenicity or immune response in younger groups, he said, the trends across age groups with the original formulations generally have been similar.
Clinical considerations
Moderna bivalent boosters will be a 50-microgram dose, while Pfizer-BioNTech bivalent boosters will be a 30-microgram dose, the same antigen amounts as the monovalent vaccines.
The boosters can be given as a single dose at least two months after vaccination with a primary series or monovalent booster. A booster can be a different brand from previous doses as long as it is age appropriate. People can get the bivalent booster regardless of how many previous boosters they have had.
People who are immunocompromised are similarly recommended to get a bivalent booster at least two months after their three-dose Moderna or Pfizer-BioNTech primary series or two-dose Novavax primary series regardless of previous monovalent boosters.
People recovering from a COVID-19 infection should not get a booster until they have recovered and met isolation criteria, according to the CDC. Then they can consider waiting three months before getting the booster.
The CDC encourages co-administration of the bivalent COVID booster with other routine vaccines, including the flu vaccine, to keep people up to date on all recommended immunizations. Co-administration has been found to be safe and immunogenic, although the CDC recommends using a different injection site and in some cases different limbs if possible. The exception on co-administration is the JYNNEOS monkeypox vaccine. The CDC recommends people consider waiting four weeks after JYNNEOS before receiving an mRNA COVID vaccine, especially adolescent or young adult males who may be at increased risk of myocarditis.
The Moderna booster will have a dark blue cap and gray label border, while Pfizer-BioNTech will have a gray cap and label border. The vials have similar color patterns as some of the COVID vaccine vials already in use, sparking concern from ACIP members.
“This is why I've been so worried about labeling issue because it’s impairing our ability to actually deliver vaccines without fear of causing any adverse events,” said ACIP Chair Grace M. Lee, M.D., M.P.H., associate chief medical officer for practice innovation at Lucile Packard Children’s Hospital in California.
Monovalent boosters no longer are authorized for use in age groups for which a bivalent booster is available. However, monovalent vaccines still are authorized for use as a primary series in people 6 months and older. The monovalent Pfizer-BioNTech vaccine also can continue to be used as a single booster for children ages 5-11 years at least five months after a Pfizer-BioNTech primary series.
There are unique Current Procedural Terminology (CPT) codes for each dose of each vaccine product, including for new bivalent booster vaccines. A full listing can be found at COVID-19 Vaccine Administration: Getting Paid.
With new vaccine products, such as the bivalent booster vaccines, there may be a delay in CPT codes being valued and loaded into payer systems. As a result, practices might consider confirming that payers have updated their payment systems prior to submitting claims.
Manufacturers plan to submit bivalent booster data for younger children later this fall.
Resources
- CDC planning guide for bivalent COVID vaccine boosters
- CDC information on COVID-19 vaccine boosters
- CDC clinical considerations for administering COVID-19 vaccines
- Information from the CDC on COVID-19 vaccination of children and teens
- AAP COVID vaccination resources
- AAP pediatric COVID-19 vaccine dosing quick reference guide
- AAP/Health and Human Services COVID vaccine toolkit
- Information from HealthyChildren.org on preparing children for a COVID-19 vaccine
