There are no COVID-19 variants yet identified in the United States that rise to the level of “high consequence” in terms of concerns such as being resistant to “multiple” treatments, according to the Centers for Disease Control and Prevention.
However, variants with certain genetic substitutions in the spike protein that is key to how the virus sticks to and infects cells are being monitored in particular for such resistance and interference with vaccines designed to provide immunity.
These variants include ones found in New England with the L452R or E484K substitution in the spike protein of the original virus.
According to CDC data, an estimated 7.8% of the COVID-19 virus in New England States contains the L452R substitution while the proportion nationally is estimated at 18%. The spike protein substitution is found in such lineages as B.1.429 and B.1.427, both first identified in California, and B.1.526.1, first identified in New York.
An estimated 13.7% of the virus in New England States is said to contain the E484K substitution with the proportion nationally estimated at 10%. This spike protein substitution is found in such lineages as B.1.525, first identified in New York, P.1 and P.2, both first identified in Brazil, and B.1.351, first identified in South Africa. It is also said to be found in some strains of the B.1.1.7 lineage, first identified in the United Kingdom and now the most common variant in the United States.
The CDC said that variants with these substitutions show either a “marked” reduction or “lower sensitivity” in laboratories studies to some therapies that use man-made proteins known as monoclonal antibodies to block the spike protein of SARS-CoV-2 from infecting the body’s cells. The therapies are authorized for emergency use by the Food and Drug Administration in patients with mild to moderate cases of COVID-19.
It is not uncommon for a virus to mutate and for a variant to have more than one mutation. Sometimes the genetic changes are harmless to a human host, but sometimes the changes benefit the virus’s ability to invade cells even when an immune system has been primed by vaccination or a prior infection to recognize it. The variant may replicate or transmit more easily and may cause more severe disease and is why variants are monitored to help both health care providers be aware of this possibility and researchers to track its spread.
The CDC list of viral groups that have evolved from the original virus includes “variants of interest” and “variants of concern” as well. These groups are also defined by how much their genetic changes enable the variant to escape detection by the body’s immune system, enhance sustained transmission, and cause more severe disease.
Its definition of a variant of high consequence is of one “clear evidence that prevention measures or medical countermeasures have significantly reduced effectiveness relative to previously circulating variants.”
The concerns around a possible variant of high consequence include those attached to the other two categories as well as others such as “evidence to suggest a significant reduction in vaccine effectiveness, a disproportionately high number of vaccine breakthrough cases, or very low vaccine-induced protection against severe disease” as well as “more severe clinical disease and increased hospitalizations.”
Vaccines are key to stopping the virus’ ability to transmit and spread, but low effectiveness against a variant can also provide information on whether other steps are needed.
The CDC said a variant found to be of “high consequence” would require it be reported to the World Health Organization.
Related content:
"able to" - Google News
April 26, 2021 at 08:12PM
https://ift.tt/3aGCXWg
CDC monitors for ‘high consequence’ COVID variants able to resist treatment, vaccines - MassLive.com
"able to" - Google News
https://ift.tt/3cA3cvs
Bagikan Berita Ini
0 Response to "CDC monitors for ‘high consequence’ COVID variants able to resist treatment, vaccines - MassLive.com"
Post a Comment