FDA’s abrupt flip-flop on Moderna’s mRNA flu shot highlights growing risks to drug-makers of investing in vaccines

Federal health officials have raised safety concerns about mRNA vaccines, although they have provided no credible data on health risks. NurPhoto via Getty Images

The Food and Drug Administration’s decision, made public on Feb. 10, 2026, to not review an application to approve Moderna’s proposed mRNA-based flu vaccine set off a firestorm of criticism from public health experts.

But just a week later, on Feb. 18, the FDA backtracked on its decision, saying that it will indeed review the vaccine, potentially in time for its approval for the 2025-26 flu season. The decision sent Moderna’s stocks soaring in a rebound from the earlier decision.