Over the past few months, new variants of the virus known as SARS-CoV-2 have started to emerge from the U.S. to the U.K. to South Africa and Brazil. Scientists have since learned that the virus has changed in ways that increase its ability to spread and may cause more severe disease.
While current evidence shows the two COVID-19 vaccines authorized in the U.S. offer good protection against the new variants, the U.S. Food and Drug Administration issued guidance earlier this week that will help vaccine makers respond more quickly to emerging variants, if needed. On Wednesday, Moderna announced it would test a booster shot that targets the South Africa variant. Pfizer also said last month it was working in a booster shot against variants.
Track the spread of the COVID-19 variants: the U.K. variant, the South African variant and the Brazilian variant. This map will be updated regularly.
At this stage, though, one thing remains clear: Existing methods to prevent transmission of COVID-19 are the still the most effective strategies, experts told TODAY. These include masking, or even double masking, maintaining social distance, not socializing unmasked and indoors with people outside your household, regular hand hygiene and getting vaccinated when you're eligible.
Here's what else you need to know about the new COVID-19 strains, from symptoms, to how lethal they are and whether vaccines will work against them.
What is a variant? How does it happen?
While the existence of new variants may be worrisome to the general public, the phenomenon is "not entirely unexpected," Ben Lopman, Ph.D., professor of epidemiology at Emory University's school of public health in Atlanta, told TODAY.
"Viruses spread by replicating themselves ... and that replication process is imperfect," he explained. "The virus makes mistakes sometimes. Most of those mistakes are useless or will kill the virus. Rarely but sometimes, one of those mistakes will be beneficial. It could, for example, make the virus more easy to transmit from person to person by changing its genetics in some way."
The U.K. variant in particular, which the CDC has said spreads "more quickly and easily than other variants," seems to replicate more efficiently, Lopman said. This could mean that infected people are "actually producing more of the virus or shedding the virus at somewhat higher levels, and that might be what makes it more transmissible," he added.
But viruses acquiring mutations isn't "necessarily a bad thing," Jasmine Plummer, Ph.D., associate director of applied genomics at Cedars-Sinai medical center in Los Angeles told TODAY.
"(Viruses) want to survive," she explained. "It's not in (their) best benefit to keep killing the host, meaning the person. Near the end, (the virus might) figure out a way ... to survive by infecting more people, but the outcome of that infection is hopefully not as severe."
How many strains of COVID-19 are there?
A new strain occurs when a virus goes through one or more mutations that change its behavior in some way, but a variant develops when a virus goes through a mutation of any kind, explained Dr. Patricia Couto, an infectious disease physician at Orlando Health in Florida.
According to Lopman, "there are many variants out there," but a few are concerning because they "appear to be spreading more quickly" and could "possibly (replace) the variants that were previously dominant," he said.
Here's a breakdown of the concerning COVID-19 variants, including the U.K. variant, South African variant and Brazilian variant, and what to know about each:
The U.K. strain, called B.1.1.7, was first reported in the U.S. in late December, and it spreads more quickly and easily than other variants, according to the Centers for Disease Control and Prevention. Dr. Anthony Fauci, the nation's leading infectious disease physician said on TODAY Thursday that it could become the dominant strain in the U.S. by the end of March. As of Feb. 23, there were 1,881 reported cases of this variant in 45 U.S. states. It's also spreading at high levels in Denmark and Scandinavia, Lopman said.
South African variant
This variant, known as B.1.351, emerged independently from the U.K. strain but shares some of its mutations, according to the CDC. Data indicates that it first emerged in South Africa in October and has since spread to other countries, including the U.S. In late January, the CDC confirmed two cases in South Carolina, and CDC director Rochelle Walensky told TODAY at the time that it had already reached the point of community spread. This variant could also make reinfection more likely; a vaccine study in South Africa found 2% of people who'd already had a version of the coronavirus had been reinfected with a variant. So far, it's been detected in 14 states, and according to Lopman, it does seem to spread more easily.
The Brazilian variant, P.1, was first detected in mid-January in travelers to Japan from the Amazonas state of Brazil. It appears to contain mutations that raise concerns about its transmissibility and potential for reinfection, according to the CDC. Manaus, the largest city in the Amazon region, saw a surge in cases in December, despite 75% of the population already having been infected by October. Five cases of this variant have been reported by the CDC in the U.S. in Minnesota, Oklahoma, Maryland and Florida.
U.S. variants in California, Ohio
A new strain known as CAL.20C now accounts for half of COVID-19 cases in Southern California, according to research from Cedars-Sinai Medical Center in L.A. To detect the strain, researchers initially looked at 10,000 COVID-19 samples from the state as far back as March and found the earliest sample of the strain in July, Plummer, co-author of the research, said. By mid-to-late January, the new strain represented more than 30% of cases in the entire state and more than 40% in Southern California.
As of mid-February, researchers had found CAL.20C in 19 states, Washington, D.C., and six foreign countries. The data at this stage suggests that it could be more easily spread than other strains.
In Ohio, researchers at Wexner Medical Center in Columbus have discovered two new strains of SARS-CoV-2. Researchers are still tracking the prevalence of both, but they've found that one of the strains became dominant Columbus, Ohio, over three weeks between December and January and suspect it's likely more infectious.
Is the new strain of COVID-19 more deadly?
Whether any of the new COVID-19 strains are more lethal depends on whether you're thinking about the individual patient or the entire population, Dr. Sten Vermund, dean of Yale School of Public Health in New Haven, Connecticut, told TODAY.
"(From) the entire society's point of view, if it's more infectious, more people get infected, then even if it's equal lethality ... you'll have more dead people," he said. "But if you're a doctor and you're trying to take care of a patient, then it may not matter which strain the patient has. Their risk of severe illness and death may be about the same."
U.K. experts reported in January that the U.K. strain may be associated with an increased risk of death compared to other variants, but more research is needed, according to the CDC. There is alsoemerging evidence that the South African strain may be more virulent, but the CDC has not confirmed that this is the case, and the same goes for the Brazilian one.
CAL.20C researchers have also said it's unclear at this stage whether it leads to more severe illness.
Another factor that can contribute to a new strain or variant being more deadly on a population scale is "how collapsed your health care system is" where it hits, Couto said. "If you have a lot of people that you did not anticipate getting sick at the same time, you will see a bump in mortality, and that doesn't necessarily mean that the virus is more lethal."
Do the new variants have different symptoms?
Currently, none of the new variants have been associated with new or different symptoms, experts told TODAY. Per the CDC, the most common symptoms of COVID-19 include:
- Fever or chills
- Shortness of breath or difficulty breathing
- Muscle or body aches
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
Couto also stressed that the new variants and strains also seem to result in the same wide range of illness that's come to be associated with COVID-19.
Are COVID-19 vaccines effective against these strains?
There's no evidence yet that the virus has mutated in ways that allow it to evade vaccines, but the research into the shots' efficacy against variants and strains is ongoing. Moderna, Pfizer, AstraZeneca and Johnson & Johnson have all released some data on how their vaccines respond to variants.
A study on Pfizer's vaccine published in Nature earlier this month found that it created antibodies that responded to virus samples that had been modified to resemble the U.K. and South Africans variants. The vaccine should protect against both but is less effective on the latter, research suggested. Pfizer has also said it's researching its vaccine's effectiveness against the Brazilian variant.
Moderna announced in late January that a lab study showed "no significant impact on neutralizing titers," which correlate to protection provided by a vaccination, against the U.K. strain. The study did find "a six-fold reduction in neutralizing titers" against the South African variant, but the company said the reduced titer levels are still expected to be protective. Still, the company has already sent booster shots targeting the South African variant to the National Institutes of Health for clinical trials.
In late January, Johnson & Johnson announced that its single-shot vaccine is effective in preventing moderate to severe COVID-19 illness but is less effective against the South African variant. The vaccine, which hasn't yet been authorized for use in the U.S., was deemed safe and effective in FDA documents earlier this week.
A small clinical trial of the Oxford-AstraZeneca vaccine earlier this month suggested it isn't effective at preventing mild to moderate illness from the South African variant, but it appeared effective against the original strain.
Plummer said her Cedars-Sinai team does not anticipate CAL.20C will evade the vaccines, but they're actively investigating to be sure.
Asked about vaccines' effectiveness against variants on TODAY Thursday, Fauci said, "We're always about variants."
"Right now, the predominant variant that's in our country variant is ... what was called the U.K. variant. ... The vaccines that we're distributing now clearly can take care of that particular strain," he continued. "Other strains ... are coming up, but the major spread in the country right now, the vaccine is good against it, and even ones in which (the vaccine) may be somewhat less effective, the vaccine is still good against severe disease."
Fauci said on TODAY in early February that the vaccines "may need to (be upgraded)." He added that it would only take two to three months for these updated doses to become available, if they're needed.
Where are the travel bans due to coronavirus variants?
According to the CDC, there are COVID-19-related travel restrictions for non-U.S. citizens who visited one of the following countries within 14 days of seeking entry to the U.S.:
- U.K. and Ireland
- South Africa
- A large portion of Europe, including Italy, France, Germany, Spain, Scandinavia and more
How might variants effect the timeline for herd immunity?
The fact that these variants exist and are spreading doesn't automatically lengthen the path to herd immunity, Vermund said. But it does make adherence to COVID-19 safety practices that much more influential in the timeline for getting back to normal.
"If we can get broader adherence to prevention messages and drive down (COVID-19) rates, even if we have these new strains circulating, we may be able to control the virus until we can get everybody vaccinated," he said. "If we just flagrantly flaunt the prevention messages, then, sure, the new strains, if they're more infectious, will affect more people and make things bad again."
This article was updated on Feb. 25, 2021.