Moderna's new COVID-19 vaccine mNexspike approved by FDA, but there's a limit on who can use it

The U.S. approved a new COVID-19 vaccine made by Moderna late Friday but with limits on who can use it — not a replacement for the company's existing shot, but a second option.

The new vaccine, mNexspike, is a step toward next-generation coronavirus vaccines. It's made in a way that allows for a lower dose - a fifth of the dose of its current COVID-19 vaccine, Spikevax - by refining its immune target.

The approval "adds an important new tool to help protect people at high risk of severe disease from COVID-19," Stephane Bancel, Moderna's CEO, said in a statement Saturday.