Omicron-tweaked boosters inch closer to release date

Two COVID-19 vaccine-makers have submitted requests to the FDA for emergency use authorization of their omicron-focused vaccines, which could be available by Labor Day.

Pfizer sent its request for its 12 and up booster Aug. 22, and Moderna followed one day later with its 18 and older option. For the updated vaccines to become available to the public, there's typically a four-step process after clinical trials: an independent FDA panel votes, the FDA declares a decision, a CDC advisory committee votes and then CDC director Rochelle Walensky, MD, MPH, gives the final OK. 

With the expectation the FDA clears Pfizer's and Moderna's submission, the CDC plans to meet Sept. 1 and 2, placing the rollout deadline as early as Sept. 5, Labor Day, according to The New York Times. The U.S. government has already bought millions of the new vaccines from Moderna. 

In a phase 3 trial, Moderna's booster candidate showed a better immune response by nearly twice as much as its predecessor, and Pfizer said its new booster elicited a "substantially higher immune response" in a phase 2/3 trial. 

When the FDA told vaccine-makers in June to tweak their vaccine formulas as omicron subvariant BA.5 rapidly dominated, the proposed deadline was October, which then got moved up to mid-September.

COVID-19 immunity has waned throughout the pandemic, prompting the new vaccines to partially include the original formula and omicron BA.4 and BA.5, which, at the time of the FDA's June decision, roughly accounted for an equal share of cases. Now, BA.5 is laps ahead of BA.4, with the former claiming 88.9 percent of infections and the latter only accounting for 4.6 percent of cases, according to CDC data.

Other subvariants, such as BA.4.6 and BA.2.75, are slowly rising, but it's unlikely for the public to need updated vaccines specifically for them, an infectious disease expert told Becker's, since the most recent emerging subvariants have similar spike proteins to BA.4 and BA.5. 

"BA.2.75 does have some changes in the spike protein, but there will be cross-protection from the new booster, according to Moderna. The question will be how long the cross-protection will last — I am not aware of any data to answer the question," Dennis Cunningham, MD, the director of infection control and prevention at Detroit-based Henry Ford Health, said. "BA.4 and BA.5 are outcompeting BA.2.75. The question is whether BA.2.75 will start to cause more cases when BA.4 and BA.5 are no longer circulating."


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