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CDC EXECUTIVE CDC EXECUTIVE
SUMMARY SUMMARY

the G614 variant spreads more quickly What is CDC doing to track emerging
than viruses without the mutation. variants of SARS-CoV-2?

Centers for Disease Control • Ability to cause either milder or more se- launched the National SARS-CoV-2 Strain
In November 2020, CDC officially
vere disease in humans. There is no evi-
dence that VOC 202012/01 produces Surveillance (NS3) program to increase the
Implications of the Emerging SARS-CoV-2 Variant VOC 202012/01 more severe illness than other SARS-CoV- number and representativeness of viruses un-
2 variants. dergoing characterization. When fully imple-

Updated December 22, 2020 mented in January 2021, each state will send
• Ability to evade detection by specific diag-
CDC at least 10 samples biweekly for se-
nostic tests. Most commercial polymerase
quencing and further characterization. In ad-
chain reaction (PCR) tests have multiple
dition, CDC’s COVID-19 response is
targets to detect the virus, such that even
actively seeking samples of interest, such as
they are “non-synonymous”), but this amino if a mutation impacts one of the targets,
Executive summary Why has this variant been in the the United Kingdom and the United States, samples associated with animal infection

A new variant strain of SARS-CoV-2 that news recently? as well as the high prevalence of this variant acid substitution does not impact the pro- the other PCR targets will still work. and, in the future, samples from vaccine-
tein’s function.
contains a series of mutations has been de- Since November 2020, a variant strain of among current UK infections, increase the • Decreased susceptibility to therapeutic breakthrough infections. Data from these ef-
VOC 202012/01 has 14 non-synonymous
scribed in the United Kingdom (UK) and SARS-CoV-2 has become prevalent in the likelihood of importation. Given the small agents such as monoclonal antibodies. forts are continuously analyzed at CDC, and

(amino acid [AA] altering) mutations, 6 syn-
become highly prevalent in London and southeast of England, reportedly accounting fraction of US infections that have been se- • Ability to evade vaccine-induced immu- genomic data are rapidly uploaded to public
onymous (non-AA altering), and 3 deletions,
southeast England. Based on these muta- for 60% of recent infections in London. This quenced, the variant could already be in the nity. FDA-authorized vaccines are “poly- databases for use by researchers, public health
notably including,
tions, this variant strain has been predicted variant has a mutation in the receptor bind- United States without having been detected. clonal,” producing antibodies that target agencies, and industry. To coordinate US se-
to potentially be more rapidly transmissible ing domain (RBD) of the spike protein at po- • 69/70 deletion: this double deletion has several parts of the spike protein. The virus quencing efforts outside of CDC, since early
than other circulating strains of SARS-CoV- sition 501, where amino acid asparagine (N) What do we know already about occurred spontaneously many times, and would likely need to accumulate multiple in the pandemic, CDC has led a national
2. Although a variant may predominate in a has been replaced with tyrosine (Y). The variants containing N501Y? likely leads to a change in the shape of (i.e., mutations in the spike protein to evade im- coalition of laboratories sequencing SARS-
geographic area, that fact alone does not shorthand for this mutation is N501Y, some- Prior work on variants with N501Y sug- a conformational change in) the spike pro- munity induced by vaccines or by natural CoV-2 (SPHERES). The SPHERES coali-
mean that the variant is more infectious. Sci- times noted as S:N501Y to specify that it is gests they may bind more tightly to the tein. infection. tion consists of more than 160 institutions,

entists are working to learn more about this in the spike protein. This variant carries many human angiotensin-converting enzyme 2 • P681H: near the S1/S2 furin cleavage site, including academic centers, industry, non-
variant to better understand how easily it other mutations, including a double deletion (ACE2) receptor. It is unknown whether a site with high variability in coron- Among these possibilities, the last—the governmental organizations, and public
might be transmitted and whether currently (positions 69 and 70). that tighter binding, if true, translates into aviruses. This mutation has also emerged ability to evade vaccine-induced immunity— health agencies. Of the approximately
authorized vaccines will protect people any significant epidemiological or clinical spontaneously multiple times. would likely be the most concerning because 275,000 full-genome sequences currently in
against it. At this time, there is no evidence Why has this variant emerged differences. In one laboratory study of trans- once a large proportion of the population is public databases, 51,000 are from the United
that this variant causes more severe illness or in the UK? mission of the virus between ferrets, this mu- • ORF8 stop codon (Q27stop): This muta- vaccinated, there will be immune pressure States. (The UK currently has the most se-
increased risk of death. Information regard- We do not know. By chance alone, viral tation (and one other) spontaneously arose tion is not in the spike protein but in a dif- that could favor and accelerate emergence of quences, with 125,000).
ing the virologic, epidemiologic, and clinical variants often emerge or disappear, and in the ferrets during the experiment. The sig- ferent gene (in open reading frame 8), the such variants by selecting for “escape mu-
characteristics of the variant are rapidly that may be the case here. Alternatively, it nificance of this observation remains to be function of which is unknown. Similar tants.” There is no evidence that this is occur- Last Updated Dec. 22, 2020
emerging. CDC, in collaboration with other may be emerging because it is better fit to elucidated. VOC 202012/01 so far has no mutations have occurred in the past. In ring, and most experts believe escape mutants Content source: National Center for Im-
public health agencies, is monitoring the sit- spread in humans. This rapid change from known association with animals or animal Singapore, one strain with this type of mu- are unlikely to emerge because of the nature munization and Respiratory Diseases
uation closely. CDC will communicate new being a rare strain to becoming a common contact. tation emerged and disappeared. of the virus. (NCIRD), Division of Viral Diseases
information as it becomes available. strain has concerned scientists in the UK,
who are urgently evaluating the characteris- What about the other mutations in What implications could the Is this new variant related to the newly
Does this variant have a name? tics of the variant strain and of the illness that this variant of SARS-CoV-2? emergence of new variants have? emergent variant in South Africa?
At present, the variant is referred to as it causes. SARS-CoV-2 mutates regularly, acquiring Among the potential consequences of On December 18, 2020, the South African
“SARS-CoV-2 VOC 202012/01” (i.e., the about one new mutation in its genome every these mutations are the following: government announced that it had also seen
first variant of concern from 2020, December), Have we seen this variant in two weeks. Many mutations are silent (i.e., • Ability to spread more quickly in hu- the emergence of a new strain in a scenario
or “B.1.1.7.” The press often uses the terms the United States? cause no change in the structure of the pro- mans. There is already evidence that one similar to that in the UK. The South African
“variant,” “strain,” “lineage,” and “mutant” in- The VOC 202012/01 variant has not been teins they encode) because they produce a mutation, D614G, has this property to variant also has the N501Y mutation and
terchangeably. For the time being in the con- identified through sequencing efforts in the three-letter codon that translates to the same spread more quickly. In the lab, G614 vari- several other mutations but emerged com-
text of this variant, the first three of these terms United States, although viruses have only amino acid (i.e., they are “synonymous”). ants propagate more quickly in human res- pletely independently of the UK strain and
are generally being used interchangeably by the been sequenced from about 51,000 of the 17 Other mutations may change the codon in a piratory epithelial cells, out-competing is not related to it.
scientific community as well. million US cases. Ongoing travel between way that leads to an amino acid change (i.e., D614 viruses. There also is evidence that

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