Although prior SARS-CoV exposure or infection may play a role in ADE, it likely is not be the predominant priming virus. Seroprevalence studies have shown a very low level of SARS-CoV seroconversion in the population apart from workers with direct contact with animals such as traders [17]. Moreover, several bat coronavirus strains [6] have been identified as being closely related to SARS-CoV-2 with higher homology than SARS-CoV. There may have been past introductions and circulations of mild strains of similar coronaviruses that were asymptomatic or mistaken for a regular common cold virus. A few potential candidates have been isolated in Hubei province [18] and may serve as the basis for retrospective serological testing to confirm prior infection and resultant risk for ADE has occurred.