The U.S. Food and Drug Administration approved Novavax’s Covid-19 vaccine, but limited its use to older adults and people over the age of 12 with conditions that put them at risk due to the illness.

Novavax originally showed its vaccine was safe and effective in a 30,000-person clinical trial. The FDA had been on track to grant Novavax full approval – without restrictions -- by its April 1 target date, according to two people with direct knowledge of the situation who spoke on condition of anonymity to discuss confidential agency matters.