COVID-19 is a respiratory illness caused by a new strain of coronavirus that first appeared in late 2019. It has sparked a global pandemic that has affected millions of people and disrupted many aspects of daily life. As of December 30, 2023, there have been over 300 million confirmed cases and 6 million deaths worldwide. The virus has continued to mutate over time, producing new variants, some of the most notable of which are Alpha, Beta, Gamma, Delta, Omicron, and JN.