Let's test this scenario: If 80% of covid deaths are among the vaccinated in a selected group what can we accurately conclude?So, to you correction for sample size is a bias?
1. That those who are vaccinated are more likely to die from covid? No.
2. That only a small percentage of the group have been vaccinated? No.
3. That a large percentage of the group have been vaccinated? Likely, but the assumption is still not proven by the raw data.
Can we conclude that the millions of Americans who have not gotten covid have not gotten covid because of the vaccine? No.
Most assumptions about the safety and affectiveness of the vaccine are unproven.