There is a a lot of research starting to show that nearly 80% of population may be immune to the coronavirus . Which would explain how people can live in homes with a person that test positive , and yet the whole family never contracts the virus . The theory is that once testing shows that approx 20% of population has tested positive , you have established herd immunity , which is why many think Italy totally fell off with cases , same with New York . If that’s indeed the case , then Sweden wouldn’t be looking at a surge of infections in the fall .
Dr. Rajkumar says immune response is more complex than just an antibody count. Studies suggest people who have not been exposed to the coronavirus have T cells that fight COVID-19. It's possible the preexisting immunity comes from exposure to other coronaviruses.
"These hot spots have had major decreases in coronavirus cases even though they are no where near that level," Rajkumar said.
Rajkumar is one of the world's leading researchers of plasma cells, which make antibodies. He points out antibody tests were done in COVID-19 hot spots after the cases dropped, presumably showing how many people had the disease.
In Lombardi, Italy, 15-20% of the population tested positive for antibodies. In Madrid, Spain, it was 10-15%. In Sweden, where no lockdowns have ever taken place serology studies find 10 to 20% positive.
Do some people have preexisting immunity to the coronavirus?
