Another vaccine trial is underway— this time for an omicron-specific vaccine dose.
“The virus can evolve very rapidly and I think the RNA approach is probably the only vaccine approach that can adapt quickly, quickly enough to really respond to variants of the vaccine,” said Dr. John Cooke, founding director of the Center for RNA Therapeutics and chair of the Department of Cardiovascular Medicine at Houston Methodist Hospital.
Cooke is one of many watching closely as Pfizer-BioNTech's work on an omicron-specific mRNA vaccine.
“Your ability to respond to the virus does wane over time and you'll need another booster, so if you can quickly generate another booster that is more specific for the common variant, that’s going to be a better booster that might last longer. You might have a longer immunity with a booster that’s more variant specific,” Dr. Cooke said.
The companies that already developed an mRNA vaccine don’t necessarily have to start from scratch just because there’s a new variant.
“So the RNA is spelling out a slightly different protein sequence. And so just change the spelling of it but put it back into the exact same packaging, the exact same formulation and you're pretty much good to go,” said Dr. Ross Kedl, who is a professor of immunology at the University of Colorado Anschutz Medical Campus. “Because they've already been through it once, doing an omicron test will be a much shorter process.”
The Pfizer study is looking at over 1,400 participants who will receive the new vaccine in three groups— a group that received two doses of the current mRNA vaccine prior, a group that received two doses and a booster, and a group that has not been vaccinated at all.
“My guess is somewhere by summer or the end of summer, you'll likely see the opportunity to get that booster,” Kedl said.
And while omicron may not be the main variant of concern by then, public health professor Aubree Gordon said it could still provide some benefits.
“I think there certainly is a hope that an omicron-specific vaccine would help to generate broader immunity and might help take us a step further towards going from a pandemic to an endemic phase,” Gordon said.
Kedl said the variants are following a pattern of other viruses.
“All viruses— the longer they are around, they tend to move in two directions just based on mathematics. They move in the direction of being more contagious and then also they tend to move in the direction of less virulent, or less dangerous to people,” Dr. Kedl said. “The likeliest scenario for SARS-CoV-2 is to move in that direction.”