SARS-CoV-2 variants are different strains of the virus that causes COVID-19. These variants arise due to mutations in the virus's genetic material as it replicates. Some variants may spread more easily, evade immunity from previous infections or vaccinations, or cause more severe illness. Scientists monitor these variants to understand their impact on public health. Notable variants include Alpha, Beta, Gamma, and Delta, each identified by specific mutations. Tracking these variants helps inform vaccine development and public health strategies to control the spread of COVID-19.