> I had a coronavirus called a cold last year; does that mean I'm immune this year? There are supposedly over 200 different viruses that can cause the common c

> I had a coronavirus called a cold last year; does that mean I'm immune this year? There are supposedly over 200 different viruses that can cause the common cold (https://www.nih.gov/news-events/nih-research-matters/understanding-common-cold-virus https://www.nih.gov/news-events/nih-research-matters/underst...). So it's quite possible for immunity to any individual strain to last a very long time and still get multiple colds per year. > Usually viruses become more transmissible and less lethal in response to rational behavior in their hosts--but humans are proving we're not rational. Our own "rationality" doesn't matter much, if a virus leaves you bed-ridden or dead, that makes it very hard for you spread it regardless of your choices. The fact that we have so many different viruses which essentially cause more or less the same "common cold" proves that there is very strong evolutionary pressure for a virus to behave this way.