The U.S. Food and Drug Administration approved Novavax's Covid-19 vaccine with age restrictions after a six-week delay.

This vaccine did previously have emergency approval by the FDA for use but can now be marketed in the U.S. for use, the letter said.

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. The vaccine's prospects were thrown into doubt after the FDA missed its April 1 target to approve the shot,