A second wave of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in India is leading to the emergence of SARS-CoV-2 variants. The B.1.617.1 (or kappa) and B.1.617.2 (or delta) variants were first identified in India and have rapidly spread to several countries throughout the world. These variants contain mutations within the spike protein located in antigenic sites recognized by antibodies with potent neutralizing activity.^1-3 We used serum samples obtained from infected and vaccinated persons to assess neutralizing activity against the SARS-CoV-2 variants in a live-virus assay.