A new study suggests current vaccines and monoclonal antibody therapies provide less neutralizing activity against the U.K. and South Africa variants of SARS-CoV-2. A new study of the U.K. and South Africa variants of SARS-CoV-2 predicts that current vaccines and certain monoclonal antibodies may be less effective at neutralizing these variants and that the new variants raise the specter that reinfections could be more likely.