Of the four genera of single linear (+)ssRNA-containing CoVs, only αCoV members (HCoV-229E and HCoV-NL63) and βCoV members (HCoV-OC43, HCoV-HKU1, SARS-CoV, MERS-CoV and SARS-CoV-2) have so far been reported to infect humans. HCoV-229E, HCoV-NL63, HCoV-OC43 and HCoV-HKU1 circulating in humans usually cause mild upper respiratory diseases [20], and there is still no vaccine or antiviral drug against these HCoVs [21]. Zoonotic SARS-CoV, a highly lethal CoV causing SARS disease, emerged in 2002. However, no SARS cases were reported after 29 April 2004 and the World Health Organization (WHO) officially announced on 18 May 2004 that the SARS outbreak had been contained [22]. Zoonotic MERS-CoV, another highly lethal CoV causing MERS disease, emerged in 2012. MERS cases are still being reported to WHO [8]. An anti-MERS drug and MERS vaccine are still not available. Zoonotic SARS-CoV-2 emerged in December 2019 and is causing the ongoing COVID-19 pandemic [11]. Many efforts are being made to develop COVID vaccines and anti-COVID drugs. As in the case of IAVs, CoVs have been isolated from a wide range of host species, and some of the isolated CoVs are zoonotic with the potential to cause an unpredictable pandemic. CoVs must therefore be controlled (Table 2).