Delta variant B.1.617.2 continues rapid displacement of SARS-CoV-2 variant B.1.1.7 in U.S.
medRxiv released an article on a study finding that the SARS-CoV-2 variant of concern B.1.617.2 from India, has displaced B.1.1.7, from the U.K, as the dominant variant in the United States, England and other countries.
Researchers from Helix, analyzed PCR testing results and viral sequencing results of samples collected across the U.S. and showed that B.1.1.7 was rapidly being displaced and is no longer responsible for the majority of new cases.
The percentage of SARS-CoV-2 positive cases that are B.1.1.7 dropped from 70% in April 2021 to 42% in just six weeks. Their analysis showed rapid growth of variants B.1.617.2 and P.1 as the primary drivers for this displacement. Currently, the growth rate of B.1.617.2 was higher than P.1 in the US (0.61 vs. 0.22), which is consistent with reports from other countries. They also showed that B.1.617.2 was growing faster in counties with a lower vaccination rate.
