The so-called clinical hold is due to a single report of nerve damage in a patient who received the combination shot in a phase two trial.

Novavax Inc.’s stock tumbled 16% early Wednesday after the company said the FDA has placed a clinical hold on its COVID-19-and-flu combination and stand-alone flu vaccine candidates, following a case of motor neuropathy in a participant in a mid-stage trial.

The U.S. Food and Drug Administration has put on hold a trial of Novavax's COVID-influenza and its standalone flu vaccines after a participant who took the combination shot reported nerve damage, the company said on Wednesday.