Emergence of SARS-CoV-2 B.1.1.7 lineage - United States, December 29, 2020-January 12, 2021

ABSTRACT

This report focuses on the emergence of the B.1.1.7 variant in the United States. As of 12 January, 2021, neither the B.1.351 nor the P.1 variants have been detected in the United States. For information about emerging SARS-CoV-2 variants of concern, CDC maintains a webpage dedicated to providing information on emerging SARS-CoV-2 variants. The B.1.1.7 variant has a mutation in the S protein that affects the binding domain of the receptor. It also has 13 other lineage-defining variants that are related to the S protein. These variants, which include a deletion at position 69 and 70, have been known to cause S-gene target failure. Multiple lines of evidence show that B.1.1.7 is a more efficiently transmitted variant of SARS-CoV-2 than other variants. In the UK, infections with this variant were more common than those with other variants. The potential increase in the number of cases of B.1.1.7 in the U.S. could affect the trajectory of the pandemic. A simple two-variant compartmental model has been developed to model this phenomenon. The potential impact of vaccinations was simulated assuming that 1 million doses were administered each day starting in 2021. It was estimated that 95% immunity was achieved 14 to 30 days after receiving 2 doses, and although B.1.1.7 is still the dominant strain, its transmission was significantly reduced after becoming the dominant variant. Currently, there is no evidence that the COVID-19 variants cause better clinical outcomes than the SARS-CoV-2 strains. However, a higher transmission rate increases the number of patients requiring hospitalisation, which could result in more deaths. The experiences of the UK and the B.1.1.7 variant illustrate the importance of having a coordinated and comprehensive approach to control the spread of this highly contagious variant. This approach involves the use of both mitigation and vaccination measures. The increased transmissibility of B.1.1.7 warrants the implementation of robust public health strategies to minimize its impact and prevent further spread. Data from the Centers for Disease Control and Prevention show that increasing the use of effective mitigation measures, such as vaccinations, is critical to curbing the spread of the disease.