A significant proportion of healthcare workers (HCWs) in the UK exposed to SARSCoV2 during the 1st wave of COVID19 never tested positive for PCR or antibodies. Instead, they controlled infection through expansion of pre-existing X-reactive T-cells.
— Prof Francois Balloux (@BallouxFrancois) November 10, 2021
1/https://t.co/ZL1UZCJOt5