The booster is an updated version of the original Moderna COVID-19 vaccine, the company shared back in June. Data from clinical trials have shown that the booster gives a “strong immune response” against the original Omicron (BA.1) and the original 2020 strain of COVID-19, according to the U.K.’s Medicines and Healthcare Products Regulatory Agency. The vaccine also reportedly shows a good immune response against Omicron sub-variants BA.4 and BA.5, which are now widely circulating in the U.S.
It’s understandable to have booster fatigue at this point, but experts say this particular one is different. Here’s what you need to know about the Omicron-specific Moderna COVID-19 booster, and when you might expect to see it in the U.S.
What is the Omicron Moderna COVID-19 booster?
The Omicron Moderna booster is specifically known as the Omicron-containing bivalent COVID-19 booster vaccine, mRNA-1273.214 (Spikevax Bivalent Original/Omicron), according to Moderna. Half of this vaccine targets the original SARS-CoV-2 virus that causes COVID-19 and half targets the original Omicron, aka BA.1.
Like other COVID-19 boosters, this is given as a single shot.
What does the data say?
Clinical trial data from phase 2/3 trials suggests this booster does its job. According to Moderna, the booster has “superior neutralizing antibody response against Omicron” compared to its regular COVID-19 vaccine. The booster increased neutralizing antibodies against Omicron by eight times, and also had “potent” antibody responses against BA.4 and BA.5 compared to the current COVID-19 booster, Moderna says.
What are the side effects of the Omicron Moderna COVID-19 booster?
Pain, swelling, and redness where you got the shot
“We anticipate more durable protection against variants of concern with mRNA-1273.214, making it our lead candidate for a Fall 2022 booster,” Stéphane Bancel, chief executive officer of Moderna, said in a press release.
Why is an Omicron-specific booster needed?
“Increasingly, people have desired protection not just against severe disease but against infection,” says infectious disease expert Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security. “Because the virus has mutated away from the ancestral strain, current vaccines don’t provide robust protection against infection and a booster reformulating to better match circulating strains of SARS-CoV-2 may provide more benefit than boosting with the ancestral strain.”
COVID-19 keeps mutating and it’s important to keep up with that in order to offer maximum protection to people, says William Schaffner, M.D., infectious disease specialist and professor at the Vanderbilt University School of Medicine. “This is very similar to what we do with influenza, another virus that is constantly mutating and changing,” he says. “We update our influenza vaccine annually in each hemisphere and it would appear we are on track to doing something similar with our COVID vaccines.”
But while it’s important to have a booster vaccine that targets the strains that are currently circulating, it’s hard to say at this point how long they’ll provide protection for, says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. “It remains to be seen how much mileage we'll get out of these boosters,” he says. “They lose efficacy over time once you get past that two- to four-month period, although they still hold up reasonably well against severe disease, hospitalizations, and death.”
When will this Omicron booster be available in the U.S.?
It’s not entirely clear at this point. The U.S. Department of Health and Human Services (HHS), shared in late July that it will purchase 66 million doses of Moderna’s COVID-19 booster for use this fall if it’s authorized by the Food and Drug Administration (FDA) and recommended by the Centers for Disease Control and Prevention (CDC).
HHS has also agreed to purchase at least 105 million doses of Pfizer’s Omicron-specific booster.
The FDA specifically said in late June that it has asked vaccine makers to create modified vaccines that targets the Omicron sub-variants BA.4 and BA.5, with the goal of having them be used by the public in early- to mid-fall.
Dr. Adalja says, though, that it’s “unclear” if this particular booster will be authorized in the U.S. “It targets BA.1, a version of Omicron that is now circulating, and the FDA had advised manufacturers to target BA.4 and BA.5,” he says. Dr. Russo agrees. “The FDA went in a slightly different direction” that what U.K. health authorities are doing, he points out.
Ultimately, Dr. Schaffner says, Americans will just need to wait and see. “We want to match what’s in the vaccine as closely as we can to provide protection against the latest variant,” he says. “But getting a new vaccine approved is not something that can be done on a schedule.”
And, if you’re eligible to get a booster vaccine now, Dr. Schaffner recommends getting it. “We don’t have this updated vaccine in hand yet,” he says. “Let’s not count our chickens before they hatch.”
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