COVID-19 is caused by a virus called SARS-CoV-2, which stands for Severe Acute Respiratory Syndrome Coronavirus 2. Viruses are unable to survive and produce more viral copies (replicate) on their own. They survive by infecting a new host that is able to be infected. After a new host is exposed to a virus, the virus infects the host’s cells. Once inside the host cells, the virus hijacks the cell’s machinery to produce more copies of the virus. This process of making new copies of a virus within a host cell is called viral replication.
As these copies are made, mistakes can happen that cause the new copies of the virus to not be exact copies of the “parent” virus. These mistakes are called mutations. Mutations happen all the time and usually don’t result in big changes to the virus. Sometimes, mutations can happen that change the virus in such a way that they change how the virus functions, such as changes to how infectious the virus is (how easy it is to spread the virus to others), the type of illness it causes, or how our immune systems respond to the virus.
Viruses constantly change through mutation and new variants of a virus, that arise from these mutations, are expected to occur over time. Multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic. Sometimes new variants emerge and disappear. Occasionally, new variants emerge that can pass more easily from one person (or host) to another.
Learn more about what causes a virus to change in this World Health Organization (WHO) video:
As more people have been infected during the COVID-19 pandemic, more variants have been documented. Scientists continually monitor the virus that causes COVID-19 to look for changes to the virus over time. This helps us better understand how the virus is changing and if these changes might affect how the virus spreads (transmissibility), how sick you could get (disease severity), and how well viral tests, treatments, and vaccines might work on different versions (variants) of the virus.
The best way to stop variants from developing in the first place is to stop the spread of the virus.
Variants have names so that scientists can communicate with one another about trends they see with certain viral lineages. These names can be pretty technical and specific and work well for scientific communications. Recently a group of scientists and experts in communications met to discuss the names we use when communicating with non-scientific audiences about certain variants. They developed a naming system, using letters of the Greek Alphabet (such as Alpha, Beta, Gamma) that are considered to be easier to pronounce and reduce stigma that can develop when a variant is referred to by the country in which it was first identified. Not all variants have a Greek letter name, but ones that the World Health Organization is monitoring closely do. On this page, we mainly refer to variants by their Greek letter name (but we kept the scientific names too because some people find those helpful!).
A variant of the virus that causes COVID-19 is considered to be concerning when it increases the risk to human health. The risk to human health could be increased because a variant is able to:
- Spread more easily
- Cause more severe illness
- Escape the immune protection provided by available COVID-19 vaccines or by natural infection with the virus that causes COVID-19
- Make viral tests less accurate
- Make some treatments less effective
Scientists have a system to categorize variants based on how concerning they are to the U.S. population.
- Variants being monitored are variants for which there is evidence that they might be of concern, but they are either no longer detected or are circulating at very low levels in the U.S., and as such, they do not pose a significant risk to public health in the United States. There are currently ten variants being monitored. These are B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.427 and B.1.429 (Epsilon), B.1.525 (Eta), B.1.526 (Iota), B.1.617.1 (Kappa), B.1.617.3 (no WHO label), P.2 (Zeta), and B.1.621 and B.1.621.1 (Mu).
- Variants of interest show some evidence that they might be of concern. There are currently no variants of interest in the United States.
- Variants of concern show evidence of being concerning. There is currently one variant of concern in the United States. This is B.1.617.2 (Delta) and its sublineages. Delta is discussed in more detail below.
- The World Health Organization (WHO) may classify certain variants in different categories because of the impacts they are having in other countries. Because the importance of variants can differ by location, the U.S. classifications may differ from those of the WHO.
- Variants of high consequence show clear evidence of making our disease prevention measures or medical countermeasures less effective. This may include demonstrated failure of diagnostic tests, more severe clinical disease, and increased hospitalizations. There are currently no SARS-CoV-2 variants of high consequence.
For more information on these categories and variants in each category, visit CDC SARS-CoV-2 Variant Classifications and Definitions.
The Delta variant is currently the only variant of concern in the United States.
|WHO/CDC Label Name||Pango Lineage Name||Where First Detected||Impact on Viral Spread||Impact on Disease Severity||Impact on Immune Protection||Impact on Antibody Therapy||Impact on Diagnostic Tests|
|Delta||B.1.617.2||India||This variant spreads more easily and quickly than other variants. Delta is more than 2x as contagious as previous variants.
Delta is, by far, the most common variant of SARS-CoV-2 in the U.S and in Virginia
|Might be associated with an increased risk of serious illness or death||Potential reduction of immune protection offered by vaccination or natural infection, but this is being monitored
Some “vaccine breakthrough infections,” meaning infections in fully vaccinated people occur, but most of these are mild.
|Potential impact on some, but not all, monoclonal antibody therapies||No real impact|
To see how commonly SARS-CoV-2 variants are being identified in the U.S. and where these variants are being identified, visit CDC’s COVID Data Tracker. To see where these variants are being identified in Virginia, visit VDH’s Variants of Concern Dashboard. To learn more about the Delta variant, visit the CDC’s Delta Variant: What We Know About the Science.
At this time, available diagnostic tests (that help us know if a person has the virus that causes COVID-19) are expected to detect existing viral variants. It is very likely that these variants are more common in our communities than the number of reported cases suggest. This is because not all COVID-19 positive samples are tested to see what variant type they are. It is important now, more than ever, that we all continue following public health recommendations to prevent the spread of COVID-19. Public health recommendations for stopping the spread of COVID-19 will work for all COVID-19 variants.
Everyone should care about variants of concern because they could threaten the progress we have made in the past few months. If they continue to spread in the United States, there could be another surge (large growth) in cases that could overwhelm our health care systems. This also means that the pandemic could go on longer and might require stronger public health measures, like stay-at-home orders, to slow the spread. With more COVID-19 cases, there would also be more people who get severely ill and die. Severe infections caused by variants might also be harder for healthcare providers to treat.
At this time, the evidence shows that available COVID-19 vaccines remain effective in protecting the American public from getting severely sick, being hospitalized, or dying from currently circulating variant strains of the virus that causes COVID-19. Every time a person is infected with the virus that causes COVID-19, there is a chance that the virus can mutate and a new variant can develop. There is a concern that with another variant, the COVID-19 vaccines might not work as well to prevent people from getting sick with COVID-19. To prepare for this possibility, vaccine manufacturers are working to create booster shots to improve protection against emerging variants. The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) continue to look at available data to see if and when booster shots might be needed.
Scientists in laboratories across the world are using advanced technologies to look at the genetic material of viruses and monitor for changes over time. CDC and other parts of the federal government are putting more funding and resources toward this specialized laboratory testing in the U.S. and have been working with state public health, academic, and commercial laboratories to closely monitor the virus that causes COVID-19, track what is happening with the spread of these variants, and detect any changes of concern. The CDC is also working with global partners to monitor the situation and coordinate prevention efforts. Additionally, to prevent new variants of the virus from being introduced into the U.S., travel restrictions went into effect in January 2021 requiring all incoming international travelers to have proof of a negative COVID-19 test before boarding an airplane to travel to the U.S.
At VDH, we have been working closely with CDC and our laboratory partners. The Division of Consolidated Laboratory Services (DCLS, Virginia’s state public health laboratory) and other highly specialized laboratories in Virginia are very actively identifying and tracking the virus that causes COVID-19 in Virginians. VDH is also sharing updated information about variants with our partners through clinician letters and the information available on our website.
With these new variants spreading, it is important now more than ever to continue to follow all the standard COVID-19 prevention measures when around other people who do not live with you in your household, especially in the presence of people who have not been vaccinated or are at increased risk of severe illness. People infected with the virus that causes COVID-19 can transmit the virus to others before they begin to feel sick.
Public health recommendations for stopping the spread of COVID-19 will work for all variants. This includes getting vaccinated for COVID-19, wearing a mask correctly, staying at least six feet from others, avoiding crowds and poorly ventilated spaces, and washing your hands often. Also, remember to stay home if you are infected with COVID-19 or if you have had close contact with someone with COVID-19 and you are not fully vaccinated. If you are fully vaccinated you can safely resume many activities that you did before the pandemic. To maximize protection from the Delta variant and prevent possibly spreading it to others, everyone should wear a mask indoors in public if you are in an area of substantial or high transmission. If you have a condition or are taking medications that weaken your immune system, you may not be fully protected even if you are fully vaccinated. You should continue taking all precautions until your healthcare provider says you no longer need to do so. You should also talk with your healthcare provider to see if you need an additional COVID-19 vaccine dose.
You should also consider downloading Virginia’s official exposure notification app, COVIDWISE, on your smartphone. This app lets you know if you’ve likely been exposed to another COVIDWISE user with a positive COVID-19 test result while completely protecting your privacy.
We’ve all been doing this for some time now, but this is not the time to let our guard down. It is more important than ever that all Virginians continue to comply with public health recommendations. The best way to stop variants from developing in the first place is to stop the spread of the virus.
Learn more about stopping the spread of COVID-19 variants in this WHO video:
- View the VDH Variants of Concern Dashboard here
- Read VDH’s FAQs on COVID-19 Variants
- Read VDH’s fact sheet How can you stay safe from COVID-19 variants
- Read VDH’s Prevention Tips to help stop the spread of COVID-19
- Download COVIDWISE, Virginia’s official exposure notification app
- More information on the new variants can be found on these websites:
- CDC: What You Need to Know about Variants
- CDC: Delta Variant: What We Know About the Science
- CDC: Understanding Variants
- CDC: SARS-CoV-2 Variant Classifications and Definitions
- CDC: Emerging SARS-CoV-2 Variants
- CDC: Genomic Surveillance for SARS-CoV-2 Variants
- CDC: Variant Proportions in the U.S.
- WHO: Tracking SARS-CoV-2 Variants
- WHO: The effects of virus variants on COVID-19 vaccines
Page last updated: September 22, 2021