ARI SHAPIRO, HOST:
There's still a lot that's unknown about the omicron variant, but COVID vaccine manufacturers are already getting ready for it. NPR pharmaceutical correspondent Sydney Lumpkin reports on what the new variant might mean for current vaccines.
SYDNEY LUPKIN, BYLINE: Omicron has more mutations than the previous coronavirus variants, around 30 mutations on just the spike protein that it uses to infect cells. And that's worrying some virologists because the spike is also the part of the virus that the vaccines use to teach our bodies to recognize. I spoke to Moncef Slaoui, who led the U.S. vaccine effort Operation Warp Speed, after decades developing vaccines in the pharmaceutical industry. Even if antibodies prompted by vaccines are less effective against omicron, other parts of the immune system could still help. Here's how Slaoui explained it.
MONCEF SLAOUI: It's a race between how fast the virus replicates and how fast the immune response gears up to eliminate it.
LUPKIN: Vaccines primed the immune system and give it memory.
SLAOUI: Then our capacity to mount a rapid immune response, I believe, will always be there to clear the virus. And clear it - maybe we'll get in for a day or two. Maybe we'd have a cough. Maybe we'd have a bit of fever. But we're not going to have severe disease.
LUPKIN: Slaoui says the vaccines do more than just create antibodies. They also create a cellular response, which includes B cells and T cells. T cells in particular should be able to recognize and react to parts of the omicron variant called epitopes, even if the spike protein is different.
SLAOUI: There's still a lot of potential T cells epitopes because spread all over the sequence of the protein, and therefore that's what makes me more cautiously optimistic. But clearly, we need to wait for the data.
LUPKIN: Vaccine manufacturers are already gearing up just in case. Moderna says it is working quickly on an omicron-specific booster. Earlier today, Pfizer's CEO Albert Bourla told The Wall Street Journal the company could have an omicron-specific vaccine ready by March. When will it be clear if a new vaccine is needed? Slaoui remembers talking with colleagues at the National Institute of Allergy and Infectious Diseases about how to respond to new variants.
SLAOUI: It will be very important to have preestablished criteria with what triggers the fact that we start immunizing people again.
LUPKIN: To him, that's if the hospitalization rate among people who are vaccinated is significantly higher with a new variant than it was with the previous variant because, ultimately, the vaccine is meant to reduce severe disease rather than prevent every case of COVID. If omicron boosters are needed, there's some flexibility in how the Food and Drug Administration would judge them. I also spoke to Norman Baylor, a former director of the FDA Office of Vaccines Research and Review. While stressing that it's not yet clear if a new booster will be necessary, he said a look at how the agency authorized existing boosters sheds light on what FDA would require for an omicron-specific booster.
NORMAN BAYLOR: They required some clinical data. The data was immunogenicity data or antibody response data in individuals who had received the other vaccine.
LUPKIN: Because this is a new variant, the agency may require a little more data this time around. But don't expect it to take as long as it did to study the first round of vaccines. This is where the mRNA technology comes in, Slaoui says.
SLAOUI: The beauty of the technology is that it's so flexible.
LUPKIN: Within an mRNA vaccine, it's easier to switch to a new variant than it would be with other kinds of vaccines. Slaoui says that between a week and 10 days after scientists first learn the sequence of a new variant, they can tweak the vaccine and begin to manufacture some doses right away for study in animals. He says it would take three months to design, produce, test and file a new vaccine with the FDA. It can happen this fast because scientists are building on what they've already learned over the course of the pandemic. Sydney Lupkin, NPR News.
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