The first erroneous assumption SAGE makes is that “100% of the population was susceptible to the virus and that no pre-existing immunity existed.” 
Yeadon states this notion is “ridiculous because while SARS-CoV-2 is indeed novel, coronaviruses are not. There’s no such thing as an ‘ancestor-less virus’.” Indeed, he points out, there are at least “four, endemic, common-cold inducing coronaviruses … [which] circulate freely in UK and elsewhere.” Those who have been infected by “one or more of these endemic, common-cold producing coronaviruses in the past, have a long-lived and robust [T-cell] immunity, not only to those viruses, but to closely related viruses. SARS-CoV-2 is one such closely-related virus.”

https://www.lifesitenews.com/n....ews/former-pfizer-vp