COVID-19 is a highly contagious disease resulting from an infection with SARS-CoV-2, a type of coronavirus. As it spreads, the virus can mutate, forming new variants. Some of these viral variants may spread more easily or lead to more severe illness.

Viruses continually mutate, and some of these mutations lead to new variants of viruses over time.

Many of these changes do not affect a virus’s capacity to spread or cause illness. Other mutations may make a virus less infectious — while still others can cause a virus to become more dangerous.

Vaccines may be less effective against a variant than against the virus that they were initially developed to combat.

However, researchers can identify which variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are more prevalent and prepare vaccines to counter them. This process also takes place with annual flu vaccines.

Vaccinations are one way that people can protect themselves and others from coronavirus disease 19 (COVID-19). Getting vaccinated is crucial, as SARS-CoV-2 can cause severe illness.

When a person also takes other precautions, such as wearing a mask and physical distancing, getting vaccinated can significantly reduce the risk of infection with SARS-CoV-2, also known as the novel coronavirus, or one of its variants.

In this article, we look into some of the more notable variants of SARS-CoV-2 and whether available vaccines can counter them. We also explore how viral mutations occur.

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Multiple variants of the virus that causes COVID-19 may be circulating globally. Many variants have mutations in their spike protein, a part of the virus responsible for binding to and infecting human cells.

Notably, mutations in the N501Y and E484K parts of the spike protein may allow the virus to spread more easily. These mutations may also affect the immune system’s antibody response.

At present, the most notable SARS-CoV-2 variants, sometimes called variants of concern (VOC), include:

  • B.1.1.7 lineage: This is also called 20I/501Y.V1 or VOC 202012/01. Experts believe that it first emerged in the United Kingdom in September 2020. It has a mutation in the receptor binding domain of the spike protein at position N501Y.
  • B.1.351 lineage: Also known as 20H/501Y.V2, this variant has multiple mutations in its spike protein, including at positions K417N, E484K, and N501Y. Scientists first identified it in South Africa around October 2020.
  • P.1 lineage: Also known as VOC 202101/02, this variant is a descendant of the B.1.1.28 lineage. Experts first identified it in four travelers from Brazil in Japan in January 2021. It contains mutations in the K417T, E484K, and N501Y positions of the spike protein’s receptor binding domain.

Viruses constantly mutate. Each time a virus replicates, or makes copies of itself in the host’s body, there may be small genetic changes that result in mutations.

Scientists may refer to a virus with a mutation as a “variant” of the original virus.

Different variants have different characteristics. Many mutations may not have significant effects because they do not alter important proteins. A mutation in an important protein, such as SARS-CoV-2’s spike protein, may allow the virus to spread more easily or cause more severe disease.

If a mutation proves beneficial for the virus, the variant may begin to outpopulate other variants.

Significant mutations are less common than insignificant ones. However, it is crucial that scientists keep track of mutations because some can result in changes to the transmissibility of the virus and the clinical presentation and severity of resulting illness.

Other changes may make the virus harder to detect or better able to evade the immune system.

The Global Initiative for Sharing Avian Influenza Data, better known as GISAID, now provides tracking information about multiple variants of SARS-CoV-2. For example, it reports that most cases involving the B.1.1.7 variant have occurred in the U.K., Denmark, Belgium, the United States, and France.

The Centers for Disease Control and Prevention (CDC) note that in the U.S., COVID-19 cases have resulted from infections with all three of the more notable variants:

  • B.1.1.7: 2,400 cases in 46 jurisdictions
  • B.1.351: 53 cases in 16 jurisdictions
  • P.1: 10 cases in five jurisdictions

It is worth noting, however, that these figures are estimates based on sampling from SARS-CoV-2-positive specimens and do not represent the total number of cases or variants in the U.S.

Research is ongoing, but currently, no evidence indicates that any new variant causes more serious illness. However, some may spread more easily and quickly.

For example, the B.1.1.7 variant may be 30–50% more transmissible than the original virus.

Some evidence suggests that this variant may also be associated with a slightly higher risk of death, but the researchers acknowledge that the absolute risk of death remains low.

Meanwhile, a preprint study has found that the B.1.1.7 variant is more transmissible — but does not lead to significantly more severe or persistent COVID-19. Overall, drawing a conclusion on this point will require more research.

It is important for scientists to continue monitoring new variants and their characteristics. Emerging variants may be able to:

  • spread more quickly
  • cause more severe disease
  • avoid detection in routine testing
  • resist treatment to a greater extent
  • evade natural or vaccine-induced immunity

Genomic surveillance of SARS-CoV-2 variants allows researchers to identify new specimens and sequences of the virus. This enables them to investigate the effects on viral transmission, disease severity, and the usefulness of vaccines and medicines.

Genomic sequencing is a laboratory technique that involves reading genetic code, and it allows scientists to identify variants of SARS-CoV-2 and their characteristics. Many scientists throughout the world are collaborating to monitor the virus and understand how it is changing.

Researchers designed current vaccines to prevent COVID-19 caused by earlier variants of SARS-CoV-2.

Evidence suggests that available vaccines can protect against new variants, too, but possibly not quite as well.

For example, results from a preprint study suggest that the Pfizer-BioNTech vaccine still provides protection against the new variants but is slightly less effective.

A preprint study from the Oxford-AstraZeneca vaccine team indicates that this vaccine offers just as effective protection against the B.1.1.7 variant but slightly less protection against the B.1.351 variant.

However, the researchers conclude, the vaccine still protects against severe illness resulting from this variant. The World Health Organization (WHO) still recommend getting this vaccine.

Meanwhile, initial laboratory tests of the Moderna vaccine suggest that it is effective against the B.1.351 variant. But, the resulting immune response may not be as strong or long-lasting when faced with this variant, the preprint study indicates.

Every approved COVID-19 vaccine can provide some level of protection from the disease. And emerging evidence suggests that protection against severe disease is still high, even when a new variant is involved.

It is also worth noting that scientists can redesign vaccines to make them more effective against new variants.

Vaccines prompt the body to develop immunity to a virus without developing an infection.

A vaccine might achieve this using an inactive form of the whole virus, parts of the virus, or just the genetic material of the virus.

There are three main approaches to developing a vaccine:

  • Vector vaccines: This type contains a weakened or inactive virus. Because the virus is not fully functional, it is unlikely to cause illness. Exposure to it prompts the immune system to develop a successful way to combat the infection. The immune system “remembers” this method and uses it if it encounters the virus in the future. The Oxford-AstraZeneca vaccine is a vector vaccine.
  • Protein subunit vaccines: This type uses parts, or subunits, of the virus. They are harmless but they teach the immune system to recognize the virus’s proteins and ward off future infections. The Novavax vaccine candidate is a subunit vaccine.
  • mRNA vaccines: Using the virus’s genetic material, this type instructs our cells to make a harmless protein that is present on the surface of the virus. The immune system then recognizes the protein and develops a response that protects against future infections. Both the Pfizer-BioNTech and Moderna vaccines are mRNA vaccines.

Click here to learn more about how COVID-19 vaccines work.

When viruses replicate within the body, there can be errors in their genetic code that result in mutations. These mutations lead to variants of the original virus.

Many mutations cause no noteworthy difference, but some can cause a virus to spread more easily or lead to more serious illness.

Multiple variants of SARS-CoV-2 may be circulating, and experts are vigilantly monitoring them for significant changes.

Currently, the evidence suggests that available vaccines protect against the new variants, as well as the original form of the virus.

Coronavirus data

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub for the most recent information on COVID-19.

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