While it is possible to buy the N95 respirator online, Schaffner advised against it. For one thing, there are just seven cases of coronavirus in the United States at this point. Meanwhile, influenza will infect, hospitalize and even kill thousands upon thousands of Americans this year, but most people aren't thinking of taking the same precautions for that illness, he said. Furthermore, while there is no shortage of the respirators now, there could be if too many people unnecessarily buy one, Schaffner said.