The Food and Drug Administration is expected to approve new COVID-19 booster shots this week — before the vaccines are tested on humans, according to a new report by the Wall Street Journal.
The new boosters are similar to the COVID vaccines currently available in the US with minor modifications that protect recipients from the latest version of the Omicron variant.
Instead of waiting for data from testing in humans, the agency will use data from trials in mice — as well as the real-world evidence of the safety of currently available COVID vaccines and test results from earlier iterations of boosters targeting older strains — to evaluate the newest boosters, FDA Commissioner Dr. Robert Califf said.
“Real world evidence from the current mRNA COVID-19 vaccines, which have been administered to millions of individuals, show us that the vaccines are safe,” Califf said on Twitter. “As we know from prior experience, strain changes can be made without affecting safety.”
He added that modifying existing vaccines to include protection against different viral strains doesn’t require a change in ingredients and is a common practice of the FDA with flu vaccines.
“FDA has extensive experience with reviewing strain changes in vaccines, as is done with the annual flu vaccine,” Califf said.
Both Moderna and Pfizer-BioNTech have submitted new COVID vaccine boosters to the agency for approval and the FDA hopes to roll out a booster campaign this fall.
However, some health experts are wary of the decision to release the shots without completed human trials.
In June, two experts penned an op-ed demanding that the FDA not rush through the rollout of the newest shots.
“I’m uncomfortable that we would move forward — that we would give millions or tens of millions of doses to people — based on mouse data,” one of the authors, Paul Offit, told the Journal.
Offit, an FDA adviser and director of the Vaccine Education Center at Children’s Hospital of Philadelphia, believes the comparison between flu shots and COVID-19 shots is not well grounded due to the differences in mutations and protection levels.
The FDA will not convene another meeting to gather input from advisers on the vaccine approvals as was done in earlier rollouts, either.
Califf said advisers already “overwhelming[ly]” voted to include an Omicron component in COVID-19 boosters at a meeting in June.
“The agency feels confident in the extensive discussion that was held in June,” he said.
COVID-19 vaccines now on the market are not as effective against newer strains of the virus, including the newest Omicron subvariant BA.5.
Pfizer and Moderna both said current data proves the newest shots are safe and effective, according to the Journal.
The newer versions are only ever so slightly changed to protect against new variants, according to several experts. Also, testing on the two companies’ earlier versions targeting earlier strains has proved successful and safe. One such shot has already been approved in the UK.
Moderna has already begun human trials on the newest subvariant-targeting vaccine and Pfizer is expected to begin such tests this month, but results will not be available before the vaccines are brought to the general public.
“If we waited for clinical-trial results, thank you very much, we’d get them in the spring. It takes time to do clinical trials,” William Schaffner, professor of medicine at Vanderbilt University Medical Center, told the Journal. “This is just an updating of the previous vaccine that we used.”