The Virus
SARS-CoV-2 is classified in the Coronaviridae family andbetacoronavirus genus and is the seventh coronavirus known to infect humans.1 Whereas four coronaviruses, HKU1, NL63, OC43 and 229E, are associated with mild symptoms akin to the common cold, SARS-CoV, MERS-CoV, and SARS-CoV-2 have each had recent outbreaks associated with a more severe disease.23This positive-sense single-stranded RNA virus has a helical capsid formed by nucleocapsid (N) proteins as well as an enveloped coated with trimeric spike (S) proteins.1 SARS-CoV-2 infection begins with viral entry through binding of the SARS-Co-V-2’s S protein to the angiotensin-converting enzyme 2 (ACE2).24,25TMPRSS2, a transmembrane serine protease, assists in viral entry though cleavage of the S protein allowing for fusion of the viral membrane with the host cell membrane. Once intracellular, replication occurs via RNA-dependent RNA polymerase.