Well, a very large number of people got infected before they were even eligible to be vaccinated. So it is what it is. I have also heard that the severity of i

Well, a very large number of people got infected before they were even eligible to be vaccinated. So it is what it is. I have also heard that the severity of infection could determine the strength of immunity, but the studies done since then haven't found that to be the case. It may become more clear on a longer timeframe, but as of now who knows.