At the end of 2019, a novel coronavirus was identified as the cause of a cluster of pneumonia cases in Wuhan, a city in the Hubei Province of China. The severity and rapid spread of COVID-19 (caused by SARS-CoV-2), resulted in a global pandemic declared by the World Health Organization in March 2020. The virus has spread to more than 100 countries, including the United States. Researchers have confirmed that the virus has spread via human-to-human transmission. Full-genome sequencing and phylogenic analysis indicated that the coronavirus that causes COVID-19 is a beta coronavirus in the same subgenus as the severe acute respiratory syndrome (SARS) virus (as well as several bat coronaviruses), but in a different clade. The structure of the receptor-binding gene region is very similar to that of the SARS coronavirus, and the virus has been shown to use the same receptor, the angiotensin-converting enzyme 2 (ACE2), for cell entry. The Middle East respiratory syndrome (MERS) virus, another beta coronavirus, appears more distantly related. It appears likely that bats may be the primary source of the coronavirus that causes COVID-19 as its RNA sequence is most similar to that of 2 bat coronaviruses. A safe and effective vaccine may be the best way to prevent SARS-CoV-2 transmission and infection. To date, no vaccine has been approved by the FDA, but a range of vaccine candidates are under development.