The three variants noted by Butler—which first emerged in the U.K., South Africa, and Brazil—are all either more transmissible, more likely to cause severe disease, or better at evading the antibodies generated by vaccination or a previous infection. Some have a combination of these traits.
With these new variants on the rise, Americans should prepare for another potential COVID-19 resurgence in the U.S. in the coming months, according to a Johns Hopkins Bloomberg School of Public Health report released Feb. 16, which analyzed current variants of concern as well as those that may be problematic in the future.
Here are answers to questions you may have about these coronavirus variants.
Why Do Viruses Mutate?
Infectious disease experts note that viruses always mutate. This virus is no different, acquiring and losing genetic traits as it spreads.
Viruses such as SARS-CoV-2, which causes COVID-19, make imperfect copies of themselves as they move from person to person or from an animal to a person. This leads to constant mutations and new variants, says Peter Katona, MD, an infectious disease specialist and clinical professor of medicine at the David Geffen School of Medicine at UCLA. The term “variant” describes a strain of the virus with a specific set of mutations.
These mutations often don’t provide any advantage to the virus. But sometimes a mutation can make a virus more transmissible or change the severity of the disease the virus causes. When the same mutation emerges in multiple places, as has been seen with aspects of variants first detected in South Africa and Brazil, it could indicate that these mutations provide some advantage for the virus—making it easier to spread or to evade antibodies, for example.
What Concerning Variants Are on the Rise?
The SARS-CoV-2 virus first emerged in China and continued to mutate as it spread around the globe. A variant of that virus that was probably more contagious emerged in Europe, Katona says. That variant’s infectiousness helped it spread rapidly throughout Europe and the U.S., where it became one of the most dominant variants.
This variant has a large number of mutations, according to a report from the European Centre for Disease Prevention and Control (ECDC), including changes to the spike protein that the coronavirus uses when infecting cells. The CDC estimates this variant is approximately 50 percent more contagious.
And while initial reports from Public Health England indicated that B.1.1.7 wasn’t causing more severe disease, a growing body suggests that cases of this variant are significantly more likely to lead to hospitalization or death. The latest data indicates this variant is more than 30 percent more likely to cause severe illness (PDF).
Even if this variant wasn’t more likely to cause severe disease, a more infectious variant would still lead to more deaths and severe cases in the long run because cases could grow exponentially, putting already strained hospital systems under further pressure, says Gregory Poland, MD, a professor of medicine and infectious diseases, and director of the Vaccine Research Group at the Mayo Clinic.
The major concern with the variants that first emerged in South Africa and Brazil, which were both detected in the U.S. in January, is the possibility that mutations have made them better at avoiding the antibodies that can fight off the coronavirus. This could make vaccines less effective and increase the likelihood of reinfection.
And as with the variant that was first identified in the U.K., these variants also appear to be more transmissible than those currently most common in the U.S.
Where Are These Variants Spreading?
Cases of the B.1.1.7 variant first emerged in the U.K. in September, primarily in southeast England, according to the ECDC and the CDC. By December, cases were also identified in Wales, Denmark, Belgium, the Netherlands, Australia, Canada, and dozens of other countries.
The first known case in the U.S. was identified on Dec. 29 in Colorado, in someone with no travel history. Within days, additional cases began popping up in other states.
As of Feb. 14, there have been more than 1,100 cases of B.1.1.7 identified in about 40 U.S. states, though many more are likely undetected. In a preliminary study released Feb. 7, researchers confirmed that B.1.1.7 cases were doubling in the U.S. every 10 days, confirming CDC projections from January that this variant is on track to become the dominant U.S. strain sometime in March.
The U.S. does less routine virus sequencing than some other countries, including the U.K., which makes it more difficult to know how widespread the variant may be here. (Sequencing is the kind of analysis scientists do to determine the variant of a virus causing a particular case or a particular outbreak.) By late December, viruses had been sequenced in just 51,000 of the 17 million COVID-19 cases in the U.S., according to the CDC.
“I would not be surprised of the existence of additional novel strains within the populace, ones that have yet to be identified,” says James Dickerson, PhD, chief scientific officer for Consumer Reports.
Public health officials are ramping up their sequencing efforts, Butler says. On Feb. 17, the White House announced that the CDC would invest $200 million to increase sequencing from about 7,000 samples per week to approximately 25,000. That should help provide a clearer picture of how widespread the variant is in the U.S.
The variant that was first detected in South Africa has been found in at least 40 countries, with at least 17 cases detected in the U.S. The variant that first emerged in Brazil has been found in at least 19 countries, with at least three cases detected in the U.S.
What Variants Have Emerged in the U.S.?
In addition to the already described variants, which are often called “variants of concern,” researchers are also tracking many other variants of the virus.
In many cases, it’s not yet clear whether the mutations observed in lesser-known variants will help or harm the virus’s ability to spread. But some data does raise concerns about several of the potential variants that have emerged in the U.S.
In California, a variant that first emerged in July in a single case and then re-emerged in October started to spread rapidly in November and December. As of late January, it accounted for almost half of the COVID-19 cases in Southern California, and had spread to at least 19 states, Washington, D.C., and six other countries, according to a study published in JAMA. Though it’s not yet clear whether this variant is more transmissible or causes more severe disease, researchers are investigating that possibility.
And the California variant is not the only one first detected in the U.S. that has raised questions. A new preliminary study published Feb. 14 identified seven virus variants in the U.S. with the same mutation in the spike protein the virus uses to infect human cells. Though more research on these variants is needed, it’s possible that the parallel evolution of the same mutation means this mutation makes it easier for the virus to spread.
Still, it’s also possible that holiday travel or some other factor is responsible for the spread of certain variants, instead of increased transmissibility. Variants will continue to emerge as the virus continues to spread rapidly, the authors of the new variant report from Johns Hopkins wrote.
Have These Variants Spurred Travel Restrictions?
Yes. On Jan. 26 the U.S. began requiring all airline passengers entering the country to test negative for COVID-19 no more than 72 hours before departure.
President Joe Biden has also extended travel bans restricting non-U.S. citizens from traveling to the U.S. from Brazil, South Africa, the U.K., and at least 27 European countries, according to the New York Times.
How Might Mutations Affect the Vaccine?
Vaccines teach our immune system to respond to a virus by recognizing some key sign of it. Mutations that affect the parts of the virus that the immune system recognizes could undermine a vaccine’s effectiveness.
The first vaccines that were authorized in the U.S. for COVID-19, made by Moderna and a partnership of Pfizer and BioNTech, target a particular protein—the spike protein—that the coronavirus uses to infect people. So mutations of that protein could potentially make a vaccine less effective, Poland says. That’s one potential concern with the variant that emerged in Brazil, according to the CDC.
A scientific brief from the CDC says “the virus would likely need to accumulate multiple mutations in the spike protein to evade immunity induced by vaccines.”
Newly released data from trials of vaccines made by Johnson & Johnson and Novavax, however, indicate that these vaccines may not work as well against the new variants.
Initial data indicates that the Johnson & Johnson vaccine is 66 percent effective overall at preventing moderate and severe COVID-19. But breaking down data by region shows that the vaccine may be less effective against certain virus variants. Research showed that the vaccine was 72 percent effective in the U.S., compared with 57 percent in South Africa, where the new variant is the predominant strain.
Novavax representatives said its vaccine appears to be approximately 89 percent effective overall, based on a trial in the U.K., indicating that the vaccine probably works against the U.K. variant. But in a South African trial, the Novavax vaccine was 49.4 percent effective overall and 60 percent effective for HIV-negative people.
Though scientists need more data to fully understand just how much the new variants are able to evade vaccine-induced protection, trial results from South Africa do raise concerns, according to John Brooks, chief medical officer for the CDC’s COVID-19 response. Still, even if vaccine efficacy is reduced to 60 percent overall against these variants, that’s still effective enough to help stop the spread of the virus, Butler says. Plus, these vaccines still appear to be very effective at preventing severe disease.
It’s not yet clear how variants could affect the Moderna and Pfizer vaccines. Even if there’s some reduction in efficacy, as might be expected, they’re still likely to be highly effective, according to Poland. Still, we may eventually need new vaccines that target other parts of the SARS-CoV-2 virus, Poland wrote in a commentary for the journal Vaccine, where he’s the editor. Over time, new variants of the virus could very likely require booster vaccines targeted at those variants.
What Should You Do?
The same advice about stopping the spread of the virus is even more crucial now, with cases peaking and more infectious variants spreading.
“The appropriate action is caution, follow the existing procedures for mask wearing, social distancing, and minimizing the number of potential lines of exposure,” says CR’s Dickerson. Now is a good time to consider upgrading your mask.
The more the coronavirus spreads, the more it mutates, according to Poland and Katona.
“We are needlessly prolonging the duration and the severity of this pandemic by not following a simple hands, face, space paradigm,” Poland says.