More than 20% of blood donations to the American Red Cross from unvaccinated people in the first week of March had COVID-19 antibodies, according to data obtained by CNN.
A survey in Texas found 30% of children have antibodies.
30-45% have antibodies.
It is unknown how many might have T-cell immune response capability, separate for antibodies in the their blood.
A study from data collected last September found:
Their results suggest that the proportion of people who had coronavirus antibodies varied greatly among the states. New York had the highest rate, at 14.4%, followed by Louisiana at 12% and Nevada at 10%. At the other end of the spectrum, the antibody prevalence rate was 0% in Alaska, 0.6% in Maine, 1.4% in Oregon, 1.8% in Hawaii and 1.9% in New Mexico.
There are possible issues about the samples used in the study. Plus, those regions with low prevalence then had large outbreaks beginning in October and continuing into January, when they too began to see declines in cases.
The overall national R-0 value began to decline in early November based on the first derivative of the epicurve. It seems once we reached perhaps as little as 20-25% positive (depending on region) that the virus had difficulty finding new targets and began to decline. Some states, like mine, continue to have lower prevalence than most other states. Does this mean we could yet see a spike in cases? It is a race against time as vaccines roll out – but it could be another 2 months before the addition of vaccines here creates a large enough immune population.
I do not use the term “herd immunity” but think “population immunity effects” is a more accurate term.
Remember, I am a brain injured idiot with no experience in this. I do not make predictions: I make observations and ask stupid questions.