Latest COVID-19 Updates
About Variants of the Virus that Causes COVID-19
What We know
Viruses constantly change through mutation, and new variants of a virus are expected to occur. Sometimes new variants emerge and disappear. Other times, new variants persist. Multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic.
Viruses constantly change and become more diverse. Scientists monitor these changes, including changes to the spikes on the surface of the virus. By carefully studying viruses, scientists can learn how changes to the virus might affect how it spreads and how sick people will get from it.
If you think about a virus like a tree growing and branching out; each branch on the tree is slightly different than the others. By comparing the branches, scientists can label them according to the differences. These small differences, or variants, have been studied and identified since the beginning of the pandemic.
Variants in the United States
How common are these variants
What we are doing to learn more
- Spread more easily from person-to-person
- Cause milder or more severe disease in people
- Are detected by currently available viral tests
- Respond to medicines currently being used to treat COVID-19
- Change the effectiveness of COVID-19 vaccines
Learn more about what CDC is doing to track variants.
New Variant of Virus that Causes COVID-19 Detected
Since November 2020, the United Kingdom (UK) has reported a rapid increase in COVID-19 cases in London and southeast England. This rapid increase in cases has been linked to a different version—or variant—of the virus that causes COVID-19 (SARS-CoV-2). Public health professionals in the UK are evaluating the characteristics of this new variant.
What we know
Viruses constantly change through mutation, and new variants of a virus are expected to occur over time. Sometimes new variants emerge and disappear. Other times, new variants emerge and start infecting people. Multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic.
- How widely the new variant has spread in the UK and potentially around the world
- How the new variant differs from earlier variants
- How the disease caused by this variant differs from the disease caused by other variants that are currently circulating
What it means
Public health officials are quickly studying the new variant to learn more so that they can control its spread. They want to understand whether the new variant
- Spreads more easily from person to person
- Causes milder or more severe disease in people
- Is detected by currently available viral tests
- Responds to medicines currently being used to treat people for COVID-19
- Affects the effectiveness of COVID-19 vaccines. There is no evidence that this is occurring, and most experts believe this is unlikely to occur because of the nature of the virus.
Some countries have announced travel bans to and from the UK while scientists work to better understand the new variant.
Implications of the Emerging SARS-CoV-2 Variant VOC 202012/01
A new variant strain of SARS-CoV-2 that contains a series of mutations has been described in the United Kingdom (UK) and become highly prevalent in London and southeast England. Based on these mutations, this variant strain has been predicted to potentially be more rapidly transmissible than other circulating strains of SARS-CoV-2. Although a variant may predominate in a geographic area, that fact alone does not mean that the variant is more infectious. Scientists are working to learn more about this variant to better understand how easily it might be transmitted and whether currently authorized vaccines will protect people against it. At this time, there is no evidence that this variant causes more severe illness or increased risk of death. Information regarding the virologic, epidemiologic, and clinical characteristics of the variant are rapidly emerging. CDC, in collaboration with other public health agencies, is monitoring the situation closely. CDC will communicate new information as it becomes available.
ORF8 stop codon (Q27stop): This mutation is not in the spike protein but in a different gene (in open reading frame 8), the function of which is unknown. Similar mutations have occurred in the past. In Singapore, one strain with this type of mutation emerged and disappeared.
What implications could the emergence of new variants have?
- Ability to spread more quickly in humans. There is already evidence that one mutation, D614G, has this property to spread more quickly. In the lab, G614 variants propagate more quickly in human respiratory epithelial cells, out-competing D614 viruses. There also is evidence that the G614 variant spreads more quickly than viruses without the mutation.
- Ability to cause either milder or more severe disease in humans. There is no evidence that VOC 202012/01 produces more severe illness than other SARS-CoV-2 variants.
- Ability to evade detection by specific diagnostic tests. Most commercial polymerase chain reaction (PCR) tests have multiple targets to detect the virus, such that even if a mutation impacts one of the targets, the other PCR targets will still work.
- Decreased susceptibility to therapeutic agents such as monoclonal antibodies.
Ability to evade vaccine-induced immunity. FDA-authorized vaccines are “polyclonal,” producing antibodies that target several parts of the spike protein. The virus would likely need to accumulate multiple mutations in the spike protein to evade immunity induced by vaccines or by natural infection.