The UK COVID-19 variant has been detected in 41 states and Washington, DC.

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About 1,300 cases involving three mutated variants of the COVID-19 virus have been reported in the US as of February 16. While those numbers are small compared to the more than 27 million confirmed cases since the pandemic began, US health officials say these new strains are “concerning” because they appear to spread more readily than the original virus.

The Centers for Disease Control and Prevention (CDC) and other federal health agencies are tracking the spread of these strains and providing verified information about what is distinct about these variants in terms of transmissibility, vaccine effectiveness, and treatment.

Much is unknown about these strains. But all three — first detected in the United Kingdom, South Africa, and Brazil — have modifications to the COVID-19 spike protein, the part of the virus that helps it enter human cells. This mutation allows them to infect people more easily than the coronavirus strain that began the pandemic.

The CDC notes that increased COVID-19 transmission “might threaten strained health care resources, require extended and more rigorous implementation of public health strategies, and increase the percentage of population immunity required for pandemic control.”

The UK strain (B.1.1.7)

The United Kingdom variant — B.1.1.7 — was discovered in September 2020 and carries the most mutations among the variants. The CDC says it is 50% more transmissible than the original COVID-19 strain.

In January, UK-based researchers reported that this variant might be more deadly than others. However, the CDC says additional studies are needed to confirm this. There is also no evidence suggesting the strain is more severe or vaccine-resistant than the original strain.

B.1.1.7 was first detected in the US in December 2020. The most prevalent of the three mutated strains, it accounts for 98% of the variant cases in the US. There have been 1,173 reported cases of the B.1.1.7 strain in 41 states and Washington DC as of February 16. The states with the most cases are California and Florida. As of January 31, the UK strain has been detected in 70 countries.

The South Africa strain (B.1.351)

The South Africa strain — B.1.351 or 501.V2 — was detected in October 2020. It shares some mutations with B.1.1.7 but emerged independently. There is no evidence that the variant is more or less severe than the original virus, but some evidence suggests certain therapeutic antibodies may not be effective against this form of the virus. Preliminary evidence also shows that the Moderna vaccine might be less effective against this strain, but the CDC cautions that more studies are needed.

Washington, DC, and nine states — California, Connecticut, Illinois, Maryland, Massachusetts, North Carolina, South Carolina, Texas, and Virginia — have reported a total of 19 South Africa strain cases as of February 16. The strain has also been reported in over 30 countries.

The Brazil strain (P.1.)

The Brazil variant — P.1. — was first identified in travelers from Brazil tested at an airport in Japan in early January. This variant contains a set of additional mutations that may affect antibodies’ ability to recognize the strain. As of February 16, there have been three reported cases in two US states, Minnesota and Oklahoma. The variant has also been found in more than four countries.

Federal health officials say there is an ongoing need for surveillance, tracking, and vaccine deployment worldwide. A recent paper co-authored by Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, says studying virus changes may help develop a vaccine that protects against most or all variants.

Emerging SARS-CoV-2 Variants
Emergence of SARS-CoV-2 B.1.1.7 Lineage — United States, December 29, 2020–January 12, 2021

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