FDA says Moderna does not meet all criteria for Covid-19 boosters

Scientists at the US Food and Drug Administration said that Moderna has not met all of the agency’s criteria to support use of booster doses of its Covid-19 vaccine, possibly because the efficacy of the shot’s first two doses has remained strong. FDA staff said in documents that data for Moderna’s vaccine showed that a booster does increase protective antibodies, but the difference in antibody levels before and after the shot was not wide enough, particularly in those whose levels had remained high. The documents were released on Tuesday ahead of a meeting later this week of the FDA’s outside expert advisers to discuss booster doses of the vaccine.