Isn’t it the spike protein that produces immunity? The body clears the spike protein from an infections in a week or two, then ‘natural’ immunity should be gone in a week or two.
“then ‘natural’ immunity should be gone in a week or two”
Actually natural immunity can last 8 months to 20 months.
https://www.nih.gov/news-events/nih-research-matters/lasting-immunity-found-after-recovery-covid-19
https://www.medicinenet.com/script/main/art.asp?articlekey=270864