I bought a pulse oximeter in case I get COVID-19. There was a pile of them in the drug store. They are recommended for people my age. It is a remarkable gadget. It shines a light through your finger and measures the wavelength. Oxygen levels are a function of the color. Apparently, if the spO2 number goes below 90%, you should go to the hospital. That's what it says here:
https://www.comhs.org/about-us…et-one-to-warn-of-covid19
I also got a Shingrix vaccine for shingles, a more powerful replacement for the vaccine they developed years ago. It knocked me flat! Persistent ~100 deg F fever for 24 hours (so far). Vaccines are not to be trifled with. You can see why they will have to do careful testing of a COVID-19 vaccine.
I have to get a booster shot in two months. Ouch.
I got a 2-part hepatitis vaccine years ago. It was no picnic, but this was worse. I read that the hepatitis vaccine might offer some protection against COVID-19. I hope so.