First Moderna, now Pfizer-BioNTech working on booster shot amid rise of COVID-19 variants

One major concern over emerging coronavirus variants focuses on their impact on the efficacy of existing vaccines. But drugmakers appear to have countermeasures in the works.

Pfizer and partner BioNTech are developing booster shots so that their COVID-19 vaccine Comirnaty can protect against new, highly contagious variants, Pfizer CEO Albert Bourla, Ph.D., said Tuesday, according to Bloomberg.

“Every time a new variant comes up we should be able to test whether or not [our vaccine] is effective,” Bourla was quoted as saying. “Once we discover something that it is not as effective, we will very, very quickly be able to produce a booster dose that will be a small variation to the current vaccine.”

Several variants of SARS-CoV-2—the coronavirus behind COVID-19—have been found to spread more easily, raising fears that the mutations they contain may affect the potency of existing vaccines and antibody treatments. These include a so-called P.1 variant that was first discovered among travelers from Brazil, the B.1.1.7 version first found in the U.K., and B.1.351 that was reported first in South Africa.

Bourla didn’t specify which variants his firm is developing the booster against. Last week, the two companies unveiled data showing that antibodies from clinical trial participants immunized with Comirnaty could neutralize pseudovirus bearing the spike protein of the B.1.17 lineage in lab cells. At the time, the companies pointed out that for COVID-19 vaccines, it hasn’t been established what kind of reduction in neutralization might require a vaccine update.

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In response to a request for comment, Pfizer declined to specify the company’s plan in detail but pointed to its vaccine’s mRNA platform as reason to be optimistic for a quick turnaround should a change be necessary.

“If the virus mutates in a way that an update to our vaccine is required to continue to provide protection against COVID-19 disease, we believe that the flexibility of the mRNA vaccine platform will allow us to move quickly to adjust the vaccine, as needed,” it said in the statement. The flexibility refers to the ability to alter the mRNA sequence in the vaccine to cover new variants as a booster.

At this point, “the studies needed to evaluate a vaccine that encodes an updated viral antigen have yet to be determined,” the company added.

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Bourla’s comment came on the heels of Moderna saying it’s developing a booster for the B.1.351 variant after scientists found a sixfold reduction in the vaccine’s ability to neutralize the variant compared with early lineage of the virus. Even though the level is enough to protect people, the company is still launching preclinical studies and a phase 1 trial to evaluate a third booster shot.

Both Moderna’s and Pfizer’s COVID vaccines have been emergency authorized by the FDA.

Pfizer’s currently working on increasing its delivery by squeezing an extra dose out of each vial of vaccine so that healthcare providers can extract a total of six doses. Thanks to the newly updated label, Pfizer and BioNTech will deliver 120 million doses of their vaccine in the first quarter, up by 20 million from its original goal, Bourla said.