#15,716
This afternoon the CDC's MMWR has published their first detailed look at the B.1.1.7 lineage (aka UK or 501Y.V1 variant) that is already spreading in the United States. As of Wednesday, the CDC had been notified of 76 cases, across 10 states (but testing is limited, and this is undoubtedly only the tip of the iceberg).
New data is expected to be published by the CDC later tonight.
While the most studied, and internationally spread, of the recently emerging COVID variants, B.1.1.7 is not alone, and may not even be the worst of the lot. The CDC describes the 3 emerging variants of greatest concern as:
- In the United Kingdom (UK), a new variant of SARS-CoV-2 (known as 20I/501Y.V1, VOC 202012/01, or B.1.1.7) emerged with an unusually large number of mutations. This variant has since been detected in numerous countries around the world, including the United States (US) and Canada.
- In South Africa, another variant of SARS-CoV-2 (known as 20H/501Y.V2 or B.1.351) emerged independently of B.1.1.7. This variant shares some mutations with B.1.1.7. Cases attributed to this variant have been detected outside of South Africa.
- In Brazil, a variant of SARS-CoV-2 (known as P.1) emerged and was identified in four travelers from Brazil, who were tested during routine screening at Haneda airport outside Tokyo, Japan. This variant has 17 unique mutations, including three in the receptor binding domain of the spike protein.
You'll note there are multiple ways to refer to each lineage, and you'll find papers and reports using different nomenclature, depending upon where they originate. These are also not the only new variants that have recently emerged, they are only the ones that enough is known about to make them of growing concern.
We've already seen concerns expressed in Denmark, and Australia, and generally in the scientific community that a sufficiently more transmissible COVID variant like B.1.17 could become the dominant virus globally in the weeks and months ahead.
Even if this new king of the viral hill is no deadlier than its previous incarnations, a more transmissible strain equals more cases, which will force more hospitalizations - which could overwhelm medical services - and ultimately result in more deaths.
In fact, the only thing liable to stop B.1.1.7 from becoming the dominant COVID virus in the months ahead would be the emergence of an even more transmissible strain.
Today's MMWR report reveals forecasts that B.1.1.7 could become dominant in the United States by March, and concludes that this B.1.1.7 variant warrants universal and increased compliance with mitigation strategies, including distancing and masking if we are to avoid seeing our healthcare systems overwhelmed.
This MMWR report focuses on the B.1.1.7 lineage, as relatively little information is available on the other variants of concern. But I expect we'll be hearing more about those - and potentially others - in the days and weeks ahead.
In the meantime, today's early release provides a lengthy and detailed overview of what we know about the most imminent threat; B.1.1.7. Follow the link to read the report in its entirety.
Emergence of SARS-CoV-2 B.1.1.7 Lineage — United States, December 29, 2020–January 12, 2021
Early Release / January 15, 2021 / 70
Summer E. Galloway, PhD1; Prabasaj Paul, PhD1; Duncan R. MacCannell, PhD2; Michael A. Johansson, PhD1; John T. Brooks, MD1; Adam MacNeil, PhD1; Rachel B. Slayton, PhD1; Suxiang Tong, PhD1; Benjamin J. Silk, PhD1; Gregory L. Armstrong, MD2; Matthew Biggerstaff, ScD1; Vivien G. Dugan, PhD1 (View author affiliations)View suggested citation
Summary
What is already known about this topic?
A more highly transmissible variant of SARS-CoV-2, B.1.1.7, has been detected in 10 U.S. states.
What is added by this report?
Modeling data indicate that B.1.1.7 has the potential to increase the U.S. pandemic trajectory in the coming months. CDC’s system for genomic surveillance and the effort to expand sequencing will increase the availability of timely U.S. genomic surveillance data.
What are the implications for public health practice?
The increased transmissibility of the B.1.1.7 variant warrants universal and increased compliance with mitigation strategies, including distancing and masking. Higher vaccination coverage might need to be achieved to protect the public. Genomic sequence analysis through the National SARS-CoV-2 Strain Surveillance program will enable a targeted approach to identifying variants of concern in the United States
On December 14, 2020, the United Kingdom reported a SARS-CoV-2 variant of concern (VOC), lineage B.1.1.7, also referred to as VOC 202012/01 or 20I/501Y.V1.* The B.1.1.7 variant is estimated to have emerged in September 2020 and has quickly become the dominant circulating SARS-CoV-2 variant in England (1). B.1.1.7 has been detected in over 30 countries, including the United States. As of January 13, 2021, approximately 76 cases of B.1.1.7 have been detected in 10 U.S. states.† Multiple lines of evidence indicate that B.1.1.7 is more efficiently transmitted than are other SARS-CoV-2 variants (1–3).
The modeled trajectory of this variant in the U.S. exhibits rapid growth in early 2021, becoming the predominant variant in March. Increased SARS-CoV-2 transmission might threaten strained health care resources, require extended and more rigorous implementation of public health strategies (4), and increase the percentage of population immunity required for pandemic control. Taking measures to reduce transmission now can lessen the potential impact of B.1.1.7 and allow critical time to increase vaccination coverage.
Collectively, enhanced genomic surveillance combined with continued compliance with effective public health measures, including vaccination, physical distancing, use of masks, hand hygiene, and isolation and quarantine, will be essential to limiting the spread of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). Strategic testing of persons without symptoms but at higher risk of infection, such as those exposed to SARS-CoV-2 or who have frequent unavoidable contact with the public, provides another opportunity to limit ongoing spread.(SNIP)
This report focuses on the emergence of the B.1.1.7 variant in the United States. As of January 12, 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.††
(SNIP)
Discussion
Currently, there is no known difference in clinical outcomes associated with the described SARS-CoV-2 variants; however, a higher rate of transmission will lead to more cases, increasing the number of persons overall who need clinical care, exacerbating the burden on an already strained health care system, and resulting in more deaths.
Continued genomic surveillance to identify B.1.1.7 cases, as well as the emergence of other variants of concern in the United States, is important for the COVID-19 public health response. Whereas the SGTF results can help identify potential B.1.1.7 cases that can be confirmed by sequencing, identifying priority variants that do not exhibit SGTF relies exclusively on sequence-based surveillance.
Suggested citation for this article: Galloway SE, Paul P, MacCannell DR, et al. Emergence of SARS-CoV-2 B.1.1.7 Lineage — United States, December 29, 2020–January 12, 2021. MMWR Morb Mortal Wkly Rep. ePub: 15 January 2021. DOI: http://dx.doi.org/10.15585/mmwr.mm7003e2external icon.
