COVID-19: Missing on all the dialog on herd immunity and immunity generated from having recovered from contracting the virus is general natural immunity.
From the Article:
“Our team also tested uninfected healthy individuals and found SARS-CoV-2-specific T cells in more than 50 percent of them. This could be due to cross-reactive immunity obtained from exposure to other coronaviruses, such as those causing the common cold, or presently unknown animal coronaviruses. It is important to understand if this could explain why some individuals are able to better control the infection,” said Professor Antonio Bertoletti, from Duke-NUS’ Emerging Infectious Diseases (EID) program, who is the corresponding author of this study.