You cannot get COVID-19 from the vaccines. All of the vaccines currently approved for use in the U.S. give your body temporary instructions to make a protein. The Pfizer and Moderna vaccines use something called mRNA technology. The Novavax vaccine provides a more familiar type of protein-based vaccine technology. This protein safely teaches your body to make germ-fighting antibodies against the COVID-19 virus. There is no COVID-19 virus in the vaccine. None of the vaccines can change your DNA.