The original COVID-19 vaccine formula introduced in December 2020 should be retired and replaced entirely with the updated mix tailored to recent virus variants, an FDA expert panel urged in a unanimous vote this week.
But COVID’S ever-evolving mutations make that difficult. Even the strains the updated booster shot was designed to protect against are rapidly vanishing. The Centers for Disease Control and Prevention indicates that the omicron BA.4 variant is no longer circulating and that BA.5 only represents about 2% of cases nationally, edged out by XBB.1.15, which now accounts for about half of infections.
But that updated formula was only recommended for boosters to goose the immune response for the already vaccinated. Those who had not been vaccinated had to get the original vaccine, based on a now-extinct strain. Health officials said the original vaccine still showed strong protection against severe illness.
“I do think it’s important to get closer to the circulating strains,” said Dr. Paul Offit, pediatrics professor at Children’s Hospital of Philadelphia.”] “We certainly want to stop the virus from circulating,” Meissner said. “But that’s probably not going to be possible. The virus is always going to mutate and evolve and find ways to avoid the immunity humans build up.”