Like all viruses, SARS-CoV-2 changes constantly through mutation. These mutations add up and create slightly different versions of the virus, called “variants”. Sometimes, a mutation will result in the virus spreading more easily, making people sicker or making it resistant to treatment or vaccines. Currently, the CDC has found that all 3 vaccines authorized for use in the U.S. are highly effective at preventing serious illness and death from these variants. See LAC DPH COVID-19 Variants FAQs.