Natural exposure immunity evidence existed even historically from the Athenian plague of 430 BC whereby historical documents showed that recovered persons were protected when re-exposed to infection

'The same man was never attacked twice and certainly not fatally', this was known dating back 430 BC; this is natural immunity (natural acquired-adaptive immunity) that doctors disregarded for COVID

This is natural immunity, below, from 430 BC. We knew it existed yet the moronic health officials around us denied it. Criminals. For a failed gene injection. Imagine, these observations were made over 2,000 years before we ever knew about the immune system and that microbial pathogens can cause disease.

SOURCE:

https://www.gutenberg.org/files/7142/7142-h/7142-h.htm