Moderna Inc. had 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 ahead of a meeting later this week of the FDA’s outside expert advisers to discuss booster doses of the vaccine.
Moderna asks Health Canada to approve COVID-19 vaccine booster shot The FDA typically follows the advice of its experts, but is not bound to do so.