What would this data look like if all of the people with natural immunity from exposure were excluded? For example, about 33% of the American population was ex

What would this data look like if all of the people with natural immunity from exposure were excluded? For example, about 33% of the American population was exposed to COVID, according to the CDC [1] If Pfizer is 42% effective, would that effectiveness value drop even further? [1] https://www.thedenverchannel.com/news/national/coronavirus/cdc-estimates-1-in-3-americans-have-been-infected-with-covid-19 https://www.thedenverchannel.com/news/national/coronavirus/c...