claim: pre-covid-19 humoral immunity to common coronaviruses does still confer cross-protection against sars-cov-2
evidence_1: collectively, the results of our study indicate that pre-existing immunity to common coronaviruses does not confer cross-protection against sars-cov-2 in vivo.", "however, their presence did not translate into neutralizing activity against sars-cov-2 in vitro.", "importantly, we detected serum igg reactivity to common coronaviruses in the early sera of patients with severe covid-19 before the appearance of anti- sars-cov-2 antibodies.")