Summary The highly transmissible B. 1.1. 7 variant of SARS-CoV-2, first identified in the
United Kingdom, has gained a foothold across the world. Using S gene target failure (SGTF)
and SARS-CoV-2 genomic sequencing, we investigated the prevalence and dynamics of
this variant in the United States (US), tracking it back to its early emergence. We found that,
while the fraction of B. 1.1. 7 varied by state, the variant increased at a logistic rate with a
roughly weekly doubling rate and an increased transmission of 40%–50%. We revealed …

As of January of 2021, the highly transmissible B. 1.1. 7 variant of SARS-CoV-2, which was
first identified in the United Kingdom (UK), has gained a strong foothold across the world.
Because of the sudden and rapid rise of B. 1.1. 7, we investigated the prevalence and
growth dynamics of this variant in the United States (US), tracking it back to its early
emergence and onward local transmission. We found that the RT-qPCR testing anomaly of
S gene target failure (SGTF), first observed in the UK, was a reliable proxy for B. 1.1. 7 …