SARS-CoV-2 (severe acute respiratory syndrome coronavirus type 2) is a new beta coronavirus that was identified in early 2020 as the causative agent of COVID-19. Beta coronaviruses also include SARS-CoV, MERS-CoV (Middle East respiratory syndrome coronavirus), and HKU1 and OC43 human coronaviruses (HCoV) circulating as “cold viruses.”
Coronaviruses are widely distributed among mammals and birds. They cause primarily mild colds in humans, but can sometimes cause severe pneumonia and be fatal.
The main route of transmission for SARS-CoV-2 is respiratory ingestion of virus-containing particles produced by breathing, coughing, talking, singing, and sneezing. Women and men are affected by SARS-CoV-2 infection at about the same rate. However, men are more likely to become severely ill and die twice as often as women, according to one review.