If you’ve already got a pulse oximeter, start using it now, so you know the baseline of everyone in your household. Ditto thermometer, especially if you’ve got one that reads from the forehead (temporal artery) or ear. When someone starts feeling a bit ‘off’, you don’t want to be wondering “is this normal?”. Also, if you have ear or mouth thermometers, don’t forget disposable covers (or alcohol to disinfect, but rubbing alcohol’s disappeared from the shelves).

I’ve made some comments elsewhere about vitamin D deficiency (rickets) also being associated with lung damage. I’ve also read that most everyone is deficient, so maybe also start taking the RDA of vitamin D.