What you need to know about the coronavirus variants

Updated March 1 at 2:08 p.m.

Viruses are always mutating and taking on new forms. The coronavirus has thousands of variants that have been identified. But several, including variants first found in the United Kingdom, South Africa and Brazil, are highly transmissible and have sparked concerns that vaccines may be less effective against them.

The same protective measures that have warded off the virus throughout the pandemic — maintaining social distance, wearing masks and washing our hands — are even more critical in the face of more transmissible variants.

The South Africa variant (B.1.351)

Where and when was it discovered?

This mutation, also referred to as 501Y.V2, was found in South Africa in early October and announced in December, when the country’s health minister said the strain seemed to affect young people more than previous strains. This variant may have contributed to a surge of infections and hospitalizations across South Africa.

Where is it?

This mutation has been identified in more than two dozen countries, including Canada, Australia and Israel. On Jan. 28, South Carolina officials announced that this variant had affected two people there with no travel history — the first instances of this strain identified in the United States. It has since been found in at least nine other states.

What makes it different?

This mutation shares some similarities to the variant first identified in the U.K. and, like that strain, appears to be more transmissible. There is no evidence that it is more lethal. Scott Gottlieb, former director of the Food and Drug Administration, has suggested that this variant might be more resistant to antibody therapies.

There is some evidence that this variant could allow for reinfection: A man in France was in critical condition in mid-February after being infected with this strain four months after he was previously infected with the virus.

Will vaccines work?

The vaccines may have a diminished impact against this variant, but they probably will still be effective, top infectious-diseases expert Anthony S. Fauci said in January. Moderna has said its vaccine protects against the variant first identified in South Africa, with an important caveat: The vaccine-elicited antibodies were also less effective at neutralizing this mutation in a laboratory dish.

Pfizer and BioNTech released their own study, not yet peer-reviewed, that suggests their vaccine effectively neutralizes this variant, though was slightly less effective.

On Jan. 29, Johnson & Johnson said its single-shot vaccine was robustly effective in a massive global trial, but that its protection against sickness was weaker in South Africa. Biotechnology company Novavax has also indicated that its vaccine was significantly less effective during a trial in South Africa.

In South Africa, the distribution of the Oxford-AstraZeneca vaccine has been halted. The vaccine did not provide sufficient protection against mild and moderate cases caused by a new variant, health officials said.


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U.K. variant (B.1.1.7)

Where and when was it discovered?

This variant was first found in the United Kingdom, specifically in London and the nearby county of Kent, in September. It is sometimes referred to as the “Kent” variant. It has been spreading rapidly in Britain, Denmark and Ireland since December.

Where is it?

Dozens of countries, including the United States, have seen infections from this variant of the virus. The Centers for Disease Control and Prevention released a model forecast in early January that indicated the variant could become the dominant strain in the United States by some point in March. A recent study showed this variant was spreading rapidly in the United States by early February.

What makes it different?

The variant first identified in the U.K. appears more transmissible than the more common strain. Preliminary data also suggests that this strain may be 30 to 70 percent more lethal than previous mutations.

Will vaccines work?

The scientific consensus is that the vaccines will remain effective against this mutation because those inoculations provoke an array of neutralizing antibodies and other immune-system responses. Biotechnology companies Pfizer, Moderna and Novavax have said their vaccines appear to work against this variant.

Ravindra Gupta, a professor of clinical microbiology at the University of Cambridge, found in a study of older adults that the immune response triggered by the Pfizer vaccine was modestly less effective against the variant first identified in the U.K.


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The ‘Eeek’ mutation (E484K)

Where and when was it discovered?

This might best be described as a mutation within a mutation. It’s called E484K — or “Eeek,” as epidemiologists refer to it — and it’s appearing on some of the variants we describe below. It’s not brand new; it has appeared many times since the start of the pandemic, but experts have been concerned about it. It gained mainstream attention when it started to coincide with other variants that are more contagious.

Where is it?

Eeek has been seen in the variants first discovered in the U.K., South Africa and Brazil. It has also been detected in more than 200 samples of the virus sequenced in the United States since May.

What makes it different?

The Eeek mutation changes the virus’s spike protein, which is what vaccines target. By itself, this mutation does not change the virus significantly. The concern with this mutation is when it’s paired with the other variants, which could help the virus evade detection and make neutralization by the human immune system less efficient.

Will vaccines work?

Scientists are actively trying to answer this question. Clinical trial data have indicated that vaccines were less effective in preventing infections with variants in South Africa featuring the mutation. But the vaccines still dramatically lowered the chance of severe illness or death.

Semi-related to the vaccine question: One study found preliminary evidence that patients in South Africa who had survived an earlier bout with the more common coronavirus were becoming infected a second time — though not severely ill — after exposure to the variant with this mutation.


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Brazil variant (P. 1)

Where and when was it discovered?

Sequencing studies found the variant in Brazil, mainly in Rio de Janeiro, as early as July. Researchers in Japan discovered it in travelers from Brazil in January.

Where is it now?

It has been confirmed in Brazil, Peru, Germany, South Korea and Japan, among other places. On Jan. 25, Minnesota health officials confirmed the first U.S. case of this variant in a resident with recent travel history to Brazil.

What makes it different?

The variant has more than a dozen alterations, several of which are found on the virus’s spike protein, which binds the virus to a cell. Because of that, researchers think the strain is probably more transmissible. There is also some early evidence that antibodies might not recognize the P. 1 variant, which could lead to reinfection.

Will vaccines work?

There’s no strong evidence right now suggesting that vaccines won’t work against the variant first identified in Brazil. However, scientists have raised the possibility that this variant can evade antibodies, which would impact the current vaccines’ effectiveness.

Moderna announced that it would develop a new vaccine tailored to a similar variant in case an updated shot becomes necessary.


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The Denmark/California mutation (L452R)

Where and when was it discovered?

This mutation was detected in Denmark in March.

Where is it now?

A variant with this mutation was found in California this winter and became dominant there over five months. It now makes up more than half of infections in 44 of the state’s 58 counties. This mutation has also been confirmed in several other states.

What makes it different?

There is evidence that this mutation enhances the virus’s ability to bind to human receptor cells, making it more transmissible. Some scientists are urging public-health officials to declare the variant with this mutation circulating in California a “variant of concern,” which would make it the first homegrown variant with this label.

Will vaccines work?

Some scientists think this mutation might make the virus more resistant to vaccines because the mutation is in the spike protein, which enables the virus to attach to cells. But scientists also say that more study is needed before they can draw conclusions.


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The original variant (D614G)

Where and when was it discovered?

This mutation, known to scientists simply as “G,” was discovered in China in January 2020. It soon spread through New York City and Europe.

Where is it?

The “G” mutation has become ubiquitous. By July, about 70 percent of the 50,000 genomes of the coronavirus uploaded by researchers worldwide to a shared database carried the variant.

What makes it different?

Some scientists think this mutation is significantly more transmissible than the original strain of the virus. That’s because this variant has four to five times more spikes on its surface. Those spikes enable the virus to latch onto and infect cells. But other scientists still contest the greater transmissibility.

Will vaccines work?

The G variant was the dominant strain when 2020 vaccine trials took place. The Pfizer and Moderna vaccines showed a 95 percent efficacy in trials.


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How can we protect ourselves from the variants?

The same protective measures that have warded off the virus throughout the pandemic — maintaining social distance, wearing masks and washing our hands — are even more critical in the face of more transmissible variants. Those guidelines will simultaneously keep you from becoming ill from one of those variants, while making it harder for the virus to mutate in the first place.

“Viruses don’t mutate unless they replicate,” Fauci said in January.

But it’s also important for scientists to learn as much as they can about these variants, in case there are specific ways we can slow their spread. Until the research exists, we can’t make assumptions about what new variants will do.

What do the variants mean for vaccines?

“We need to get as many people vaccinated with the current vaccine that we have as we possibly can … and prepare for the potential eventuality that we might have to update this vaccine sometime in the future.” — Fauci in January

As more significant variants are reported, the obvious (and arguably most important) question is whether the vaccines will work on them. Some of the mutations have sparked particular concern because they affect the spikes on the virus, which is what the vaccines target.

In short, the pharmaceutical companies are testing new variants against their vaccines and spinning up new trials. Moderna and Pfizer-BioNTech can update their vaccines quickly because of their mRNA technology, which can be reprogrammed to target new variants.

Pfizer and Moderna have run tests on the variants and while the vaccines still triggered a response, they appeared to be less effective.

A growing number of scientists anticipate that we will eventually need something similar to the annual flu shot — companies will periodically update their vaccines to match the prevalent coronavirus variants, and we will need to get boosters to stay protected.

“With flu, we need to adapt the vaccines. We can see that already,” said Ravindra Gupta, a professor of clinical microbiology at the University of Cambridge. “The companies do realize there is a problem in the longer term, and they will deal with it just as we have done with flu every year.”


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Joel Achenbach, William Booth, Carolyn Y. Johnson, Sarah Kaplan, Laurie McGinley and Fenit Nirappil contributed to this report.

Updated February 27, 2021

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Marisa Iati is a reporter for the General Assignment News Desk at The Washington Post. She previously worked at the Star-Ledger and NJ.com in New Jersey, where she covered municipal mayhem, community issues, education and crime.
Angela Fritz is the Deputy Editor on the General Assignment News Desk. She is also an atmospheric scientist and was formerly Deputy Weather Editor on the Capital Weather Gang. Before joining The Post, Fritz worked at CNN in Atlanta and Weather Underground in San Francisco. She has a B.S. in meteorology and an M.S. in earth and atmospheric science.