Alliance for Pandemic Preparedness

May 5, 2021

Rapid Emergence and Epidemiologic Characteristics of the SARS-CoV-2 B.1.526 Variant — New York City, New York, January 1–April 5, 2021

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  • The SARS-CoV-2 B.1.526 variant, a variant of concern/interest (VOC/VOI) first described in New York City (NYC), does not appear to lead to more severe disease, increased risk of infection after vaccination, or increased risk of reinfection according to preliminary analyses of infections with sequenced virus matched to epidemiologic characteristics in NYC from January to April 2021 (n=9,765). Among individuals infected with the B.1.526 variant, 71% were symptomatic, 4% were hospitalized, and 0.5% died; these frequencies were similar or lower than among individuals infected with non-VOC/VOI infections. Prevalence of possible reinfections was similar across all sequenced specimens and was rare (0.5%). However, previous positivity for anti-SARS-CoV-2 spike antibodies was slightly more common among persons infected with the B.1.526 variant carrying the E484K mutation. Among 32 fully vaccinated persons with sequenced viruses, eight (25%) were infected with the B.1.526 variant carrying the E484K mutation, three (9%) with the B.1.526 variant without the E484K mutation, seven (22%) with the B.1.1.7 variant, and 14 (44%) with non-VOI/VOC infections. 
  • B.1526 infections (n=3,679 total) comprised 3% of all sequenced infections in mid-January, 34% by late February, and stabilized to 35-45% beginning in March. The proportion of B.1.526 infections with the E484K mutation increased more quickly, and by the end of the study comprised 25% of all sequenced infections and more than half (56%) of all B.1.526 infections.

Thompson et al. (May 5, 2021). Rapid Emergence and Epidemiologic Characteristics of the SARS-CoV-2 B.1.526 Variant — New York City, New York, January 1–April 5, 2021. MMWR. Morbidity and Mortality Weekly Report. https://doi.org/10.15585/mmwr.mm7019e1