SARS-CoV-2, which shares about 80% nt sequence identity with its elder cousin SARS-CoV [221], causes an acute respiratory disease that was officially named coronavirus disease 2019 (COVID-19). It is a novel coronavirus (2019-nCoV) that was first recognized in December 2019 in Wuhan, Hubei in Central China [222]. Different from SARS-CoV, with a mortality rate of 9.6% in cases of infection, SARS-CoV-2 generally causes mild to moderate disease, but it can also lead to severe disease and death in some cases [223,224]. Keeping the infected hosts alive enabled SARS-CoV-2 to adapt to humans with efficient human-to-human transmission. It spread rapidly worldwide, finally causing the COVID-19 pandemic, with outbreaks sustained in more than one WHO region [154], on 11 March 2020. As of 8 September 2020, the pandemic is ongoing and has caused 27,205,275 confirmed cases reported from 182 countries and 33 territories and reported from international conveyances throughout six WHO regions, resulting in 890,392 deaths, giving a tentative 3.3% case fatality rate [225].