The 400 million N95 masks amount to more than half of the 750 million stored in the Strategic National Stockpile, a figure that tripled over the past year as the White House sought to boost reserves.

Wearing a face mask when you’re in a public setting is one of the best ways to avoid getting and spreading illnesses like Covid-19, the flu, RSV and the common cold, says Dr. Carl Fichtenbaum, a ...