They also say you should wear masks, but masks have been extensively studied. Cloth masks, if anything, make you more likely to capture an unusual bacterial pneumonia, because you're breathing through a filthy cloth. And the blue medical masks are not masks, actually: they're splash guards.
Their purpose in hospitals is to stop blood and body fluids getting into the nose and mouth of the attending healthcare worker. They've never been for filtering your breath, and obviously they don't do so, but they told you to wear masks, and I think the purpose—certainly in me—it causes anxiety. I feel really awful wearing these things.