Easiest way is to look at the deaths. Covid-19 has been around for more than a year now. Flu deaths went to 0 and Covid-19 deaths were pretty much exactly what the flu numbers were.

So even taking it at the most extreme numbers, covid is basically like the flu. And you have a 99.99% chance of survival as long as you're under 65 and not obese. So if people have existing anti-bodies or not, it seems like unless your immune system is extremely compromised, that it looks like most people will be okay as long as you're in good health.