Is the theory that the first COVID vaccines (plus COVID vaccines in subsequent years - boosters) were especially safe and reduced deaths dramatically, but that people who got their first COVID vaccines in subsequent years got something that caused far more deaths than it saved, and that's why 'vaccinated' group results are so good compared to the 'unvaccinated' group? (I am guessing you have some point you're trying to get to, and that's why you're avoiding questions like whether the process mentioned in my parent comments has the absolute best expected outcomes of any possible or theoretical approach, or what the better approach is if not?)