Emergence and expansion of SARS-CoV-2 B.1.526 after identification in New York

Recent months have seen outbreaks of SARS-CoV-2 infections around the world with considerable viral evolution^1-3. Extensive mutations in spike protein may threaten efficacy of therapeutic vaccines and monoclonal antibodies⁴. Two signature mutations of concern are E484K, which plays a crucial role in the loss of neutralizing activity of antibodies, and N501Y, a driver of rapid global transmission of the B.1.1.7 lineage. Here we report the emergence of the variant line B.1.526 which contains E484K and its alarming rise to dominance in New York City in early 2021. This variant is partially or completely resistant to two therapeutic monoclonal antibodies in clinical use and less susceptible to ‘be neutralized by convalescents. plasma or vaccinated sera, posing a modest antigenic challenge. Line B.1.526 has now been reported in all 50 states of the United States and many other countries. B.1.526 quickly replaced the earlier New York lineages upon emergence, with an estimated 35% inheritance advantage. Such transmission dynamics, as well as the relative resistance to antibodies of its E484K subline, probably contributed to the strong increase and rapid spread of B.1.526. Although SARS-CoV-2 B.1.526 initially exceeded B.1.1.7 in the region, its growth subsequently slowed in line with the rise of B.1.1.7 and the resulting variants.