US regulators will not review Moderna’s request to license a new, potentially more effective flu shot – even though the US Food and Drug Administration (FDA) previously gave the green light to the project – in a decision that could have implications for all new and updated vaccines in the US.

It’s the latest move by the Trump administration against vaccines. Officials in January decided to stop fully recommending one-third of routine childhood vaccines, including flu vaccines.

“This is likely to discourage industry from investing in future influenza vaccines, and makes working with the US FDA uncertain and problematic,” said Dorit Reiss, professor of law at UC Law San Francisco.

“They are refusing to review a new vaccine with a more flexible technology, while creating a real risk we will not have traditional vaccines for next year.”