In the early days of the plandemic, it was known that antibodies from recovered patients gave them "high levels of immunity" and could be transferred to others as "human convalescent plasma."
Survivor Corps FB Entry
China used this technique to end their epidemic.

Mount Sinai Entry
Blood PLasma
But big pharma couldn't make money off it, and natural immunity was erased. And the Red Cross banned vaccinated people from donating human convalescent plasma.

Red Cross
© Real Climate Science
Wayback Machine
The Red Cross has since deleted the document from their website and insist it never existed. They also ended their convalescent plasma program.