Friedberg reports 40-60% of people have pre-existing T-cell immunity to COVID-19 from prior coronavirus exposure.
“forty to sixty percent of the population that has never been exposed to SARS coronavirus to the current coronavirus already have activated T cells to the virus.”
Friedberg cites recent paper showing 40-60% of population has T-cell immunity to COVID from prior common cold exposure.
“And the reason is that they've had other coronaviruses through a common cold and they've developed this immune response.”