- The virus that causes COVID-19 has mutated, as expected.
- Multiple mutations of the virus called variants are worrying health experts.
- There’s currently no evidence the variants will affect the effectiveness of the vaccines or cause a more severe illness.
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Since the start of the pandemic, SARS-CoV-2 has been mutating.
Most mutations are useless and go undetected, but every so often, a series of mutations will produce a variant that’s better at infecting people and making them sick.
That’s what we’re seeing now. Given the swift spread of the new variants, experts say the new strains contain mutations that could make it easier for the virus to bind to our cells.
First came the D614G variant, which showed up in Australia and India in May. In December, scientists detected the B.1.1.7 variant in the United Kingdom, followed by the B.1.351 variant in South Africa, along with new variants in Los Angeles and Ohio.
All seemed to be much more transmissible than the previous variants. Now, some research scientists suspect the B.1.1.7 variant may not only be more contagious, but also deadlier.
The research on B.1.1.7 is limited and includes a small number of patients. Experts agree that much more evidence is needed to know if the variant is linked to a higher rate of mortality.
Experts don’t expect the variants to completely evade the vaccines.
The vaccines produce a broad immune response, so even if a variant were to slightly diminish the efficacy of a vaccine, the shot would still confer some degree of protection.
The messenger RNA (mRNA) vaccines can also be easily modified to target new variants.
Moderna announced Monday, Jan. 25, that recent testing shows the vaccines are expected to work on the variants, but they’re already working on a booster shot to guard against B.1.351 lineage.
Many of these new variants are thought to be more transmissible due to mutations on the spike protein, the part of the virus that binds to human cells.
The B.1.1.7 variant, originally found in the United Kingdom, is thought to be 50 percent more contagious than previous variants. The Centers for Disease Control and Prevention (CDC) expects it to be the dominant strain in the United States by March.
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Though experts originally stated there was no proof the variants could be more virulent, new evidence from the United Kingdom suggests cases caused by the B.1.1.7 variant may be deadlier (up to 30 percent) and cause more severe disease.
However, experts say the data is limited and there’s too much uncertainty to know exactly how transmissible and virulent any of the new variants are.
The CDC is currently reviewing evidence to determine if the variant first detected in the United Kingdom is more virulent.
The B.1.351 variant found in South Africa has mutations in its spike protein, where it binds with human cells.
All viruses mutate often, but the mutations typically aren’t functional and have no significant impact on the behavior of the virus.
But as viruses mutate, their chance of survival increases. The more diverse a species is, the more chances it has to survive, said Benjamin Neuman, PhD, a virologist at Texas A&M University Texarkana.
“Mostly the changes are bad for each individual virus, but together, a population of weaker but more diverse viruses has a better chance of survival than the same sized population of identical viruses,” Neuman said.
Sometimes, those mutations can improve the performance of the virus, as we may be seeing with the new variants detected in the United Kingdom and South Africa.
“Just like a good engineer can usually find a way to optimize a machine, mutations can change the speed with which parts of a virus work,” Neuman said.
There’s also concern the mutations in the new variants could diminish the effectiveness of our vaccines.
Moderna said in a statement Jan. 25 that while its vaccine will likely work against the variant detected in South Africa, it may not be as successful against other variants of the virus.
Moderna is working on a COVID-19 booster shot that would target the variant found in South Africa.
Pfizer said on Jan. 28 that their vaccine will be slightly less effective on this variant.
The vaccines target the spike protein. If the structure of the spike protein mutates drastically, some experts fear the vaccine may not work as efficiently.
But the vaccine induces a broad immune response that’ll likely be able to recognize and respond to most variants.
“The studies of immunity of the vaccines to date are showing that even the mutations of the virus are affected by the vaccine-induced immunity, so we will not face the phenomena we see with the influenza vaccines requiring new vaccine formulations for different viral strains which emerge more popular each year,” said Dr. David Mulligan, the section chief of transplantation surgery and immunology at Yale Medicine and professor of surgery at Yale School of Medicine.
The mRNA vaccines also activate B cells that have the ability to produce antibodies over 8 months after being vaccinated, Mulligan said.
This would suggest that, once vaccinated, people will have long-term immunity and not need a booster, Mulligan added.
Even if a vaccine isn’t a 100 percent match to the circulating variants, it can still help prevent infection and disease, said Ilhem Messaoudi Powers, PhD, the director of the University of California, Irvine’s Center for Virus Research.
Look at the flu shot, for example. Even in the years where the flu shot isn’t a strong match to the circulating strains, the vaccine still confers partial protection, according to Messaoudi Powers.
“The immunity generated to the spike protein encoded by the vaccine will provide some immunity and allow our immune systems to tweak the response generated by the vaccine to be a better match for the virus we actually encounter in the event of an infection,” Messaoudi Powers said.
“I think it’s highly unlikely that there’s going to be a variant that the vaccine completely doesn’t touch,” said Dr. Ellen F. Foxman, an immunologist and Yale Medicine physician.
Neuman said the variants seem to be spreading more rapidly, and that’s the one thing we can be certain of.
“When you read about scientists suggesting things the new strain might do, you are really just seeing how an early step in the scientific process works — we think, worry, spitball, imagine, hypothesize, and just wander through a series of ‘what if’s’ until we hit on a question that might be answered with an experiment,” Neuman said.
More research is needed to conclude if and how the strains may be more transmissible or virulent.
Foxman suspects there may be other mechanisms at play, such as the population’s habits and behavior.
Additionally, the virus is already transmitting faster because it’s more widespread than it was in March. When a greater percentage of the population is infected, viruses have an easier time spreading.
“The evidence is all based on epidemiology,” Foxman said. “It’s based on looking at the fact that this strain has spread more and been a higher proportion of cases than other genetic strains of the virus.”
We don’t yet have proof that the virus is biologically better at infecting our cells, Foxman added.
If the messenger RNA vaccines end up being less effective against variants, they can be quickly reworked to target new sequences.
“That’s a big advantage of that type of vaccine,” Foxman said, noting this scenario could introduce delays in the vaccine manufacturing and distribution processes.
“SARS-CoV-2 remains about as preventable as a speeding ticket, no matter which variant we are talking about,” Neuman said.
Wearing a mask that’s tightly sealed around your face, washing your hands, and keeping a physical distance from others, especially in a crowded setting, can decrease your risk of developing COVID-19.
“Those same things work no matter what the virus is,” Foxman said.
There’s a lot to learn about the mutations. In the meantime, it’s best to stay vigilant as new variants arise.
“I expect the virus to remain in our world and for more mutations to develop,” Mulligan said. “However, with immunity, from both surviving the infection and more importantly through vaccination, we can reduce the deaths it has caused and should not need to wear masks and socially isolate for years to come.”
A number of new variants have been detected across the world, many of which are thought to be more transmissible due to a mutation on the part of the virus that binds to our cells.
Early evidence suggests one of the variants, the B.1.1.7 lineage first detected in the United Kingdom, could be deadlier. Another that originated in South Africa may be less susceptible to current vaccines
More research is needed to understand the transmissibility and virulence of these variants. The vaccines produce a broad immune response and are expected to guard against the variants.