Who needs to get an updated COVID booster? What to know about the new shots
Now that updated COVID-19 booster shots are available, you may wonder who needs the updated doses — and when to get them.
Pfizer and Moderna developed “bivalent” boosters targeting two offshoots of the coronavirus omicron variant spreading in the U.S. — the BA.4 and BA.5 subvariants. After both companies adjusted their existing COVID-19 vaccines, the shots received a green light from the Food and Drug Administration for emergency use on Aug. 31.
The BA.4 and BA.5 subvariants “have shown an ability to evade our immunity more so than any other variant yet,” Dr. Scott Roberts, a Yale Medicine infectious diseases doctor and assistant professor at Yale School of Medicine, told McClatchy News in a statement.
According to the latest virus tracking data, BA.5 accounted for about 87% of cases across the country for the week ending Sept. 10, while BA.4 made up 2% of cases, the Centers for Disease Control and Prevention estimates.
“The virus continues to mutate at a rapid pace, and our challenge is to do the best that we can to keep up with the virus,” Dr. William Gruber, senior vice president of Pfizer Vaccine Clinical Research and Development, told McClatchy News in an interview.
“We’ve discovered that the best way to do that is to make small changes in the mRNA that more closely match the target of the virus that we’re trying to attack,” Gruber added.
Here is everything you need to know about the updated COVID-19 boosters.
Who needs the updated boosters?
Individuals 12 and older are eligible to receive Pfizer’s updated booster at least two months after their second vaccine dose or booster shot, according to the CDC. Those 18 and older are eligible for Moderna’s under the same conditions.
The new shots are only meant to be used as boosters and are not replacing the original vaccines for the first two shots. For those unvaccinated, they must get the primary series first before getting an updated booster.
Given omicron BA.4 and BA.5’s immune-evading capabilities, Roberts said updates to the vaccines “that help build immunity against these new variants are needed.”
Though not all health experts agree on whether the boosters are needed for everyone, Roberts said “everyone who is eligible to get the updated bivalent booster should receive it.”
“Although when to receive it is a bit of an outstanding question, since those recently infected or boosted may get less benefit,” Roberts told McClatchy News.
For those currently infected and recently infected with COVID-19, the CDC says these individuals can “consider delaying any COVID-19 vaccination, including bivalent booster vaccination, by 3 months from symptom onset or positive test.”
Gruber, who has 35 years of experience researching and developing vaccines, also said those eligible should get the booster due to the risk of another COVID-19 surge in the winter.
Meanwhile, Dr. Paul Offit, a pediatrician at the Children’s Hospital of Philadelphia, said in an interview with MedPage Today he will not get another vaccine dose soon since he has gotten three doses of the original COVID-19 vaccines and was infected with the virus in May. He added this should protect him “against severe disease this winter.”
Dr. John Moore, of Weill Cornell Medicine in New York City, also said in an interview with MedPage Today he is not planning on getting a bivalent booster shot.
“I think we’re at the point where people need to make their own decisions. If you feel like you need a booster for medical reasons … then get one,” Moore told the outlet. “But, clearly, a booster is more important to people who are in the older age ranges and/or with pre-existing health conditions.”
What are the bivalent boosters made of?
The new boosters contain two mRNA components of the coronavirus, according to the FDA. One half contains the original virus strain, which is included in the original vaccines, and the other half contains a strain “in common between the BA.4 and BA.5 lineages.”
As for the original COVID-19 vaccines, which are considered monovalent, the shots “still provide great protection against severe disease for a period of time,” Gruber told McClatchy News.
However, “protection was beginning to erode for milder illness — illness that would still take people to the doctor and still keep them out of work and still create risk for spreading in the community,” he added. “In order to manage that, it was important to update the vaccine.”
Are the new boosters safe?
The FDA says it authorized Pfizer and Moderna’s boosters based on an evaluation of:
Safety and effectiveness data regarding the original COVID-19 vaccines
Data from both companies’ clinical studies on an “investigational” bivalent COVID-19 vaccine containing the original strain and an earlier omicron subvariant (BA.1)
Nonclinical data on the updated boosters
The updated bivalent boosters were studied in mice, while the “investigational” bivalent boosters were studied in people, Yale Medicine reports.
Current studies of Pfizer’s bivalent boosters in people are underway, and data is expected over the course of the year, Gruber said. Similar studies in people are ongoing with Moderna’s boosters, according to the University of Colorado.
The reason a bivalent vaccine containing BA.1 was studied in people, before a vaccine containing BA.4 and BA.5, is that when the decision was made to study a bivalent shot, BA.1 was the variant of most interest, as BA.4. and BA.5 were not yet circulating, according to Gruber. He said the safety profile of a bivalent shot containing BA.1 was the same as the original shots.
Additionally, the investigational BA.1 bivalent vaccine used in Pfizer and Moderna’s studies is similar to the authorized boosters targeting BA.4 and BA.5, according to the FDA.
“During the course of that investigation, it became apparent…BA.1 is no longer the flavor of the moment, it’s BA.4 and BA.5,” Gruber said.
“Based on all the experience that we had with the original vaccine, and with a bivalent containing vaccine with BA.1 … we used that to say, yes, we can move forward with a bivalent vaccine containing BA.4 and BA.5 and the FDA and CDC agreed,” Gruber added.
Dr. Peter Marks, the director of the FDA’s Center for Biologics Evaluation and Research, said in a statement that the FDA has “worked closely with the vaccine manufacturers to ensure the development of these updated boosters was done safely and efficiently.”
What about side effects?
It’s possible for those who receive the updated boosters to experience side effects similar to those reported from previous shots, according to the FDA.
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.
How long will boosters provide protection?
Roberts told McClatchy News that he expects “the protection against getting infected and transmitting to others to last for 1-2 months after the booster.”
“But I expect the protection against severe disease such as hospitalization and death to last much longer, months if not greater than a year,” Roberts added.
Gruber said since these bivalent boosters are new, “there could be some expectation that this could do better.”
It is possible that updates to COVID-19 vaccines to keep up with circulating variants may become more regular going forward.
“It’s really going to be dictated by what nature puts in front of us,” Gruber said.
In the U.S., more than 224 million people have been fully vaccinated with a primary vaccine series of two doses, and nearly 109 million people have gotten their first booster dose as of Sept. 14, according to the CDC.
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