Scientists Warn Future Coronavirus Mutations Could Evade Vaccines and Treatments
Vaccinating quickly is more important than ever
The relentless surge in Covid-19 cases coupled with an emerging and more contagious strain, if not contained promptly, could allow the coronavirus to mutate and evolve enough to evade existing treatments and vaccines. While infectious-disease experts say such scenarios are not a certainty and could take months or more to play out, there’s widespread agreement on the urgency to take action now to reduce that risk.
Slow vaccine rollout amid already out-of-control virus spread, along with the recent emergence of a mutated strain thought to be about 50% more contagious, have created a “perfect storm” that “could undermine diagnostic testing, antibody treatment, and vaccine efficacy,” says Tom Frieden, MD, former head of the U.S. Centers for Disease Control and Prevention.
It’s a battle Frieden dubs humanity vs. virus. “The virus is winning,” he notes, in the understatement of the year so far.
By all accounts, the two Covid-19 vaccines approved for use in the United States remain highly effective for now — immunity is not 100% but a high level of it appears to last at least eight months for most people, and perhaps longer, research suggests. But to save lives and to reduce the number of further mutations, urgent efforts are needed to staunch the spread, particularly of the worrisome emerging strains, also called variants, of the Covid-causing coronavirus SARS-CoV-2.
Krutika Kuppalli, MD, an assistant professor of infectious diseases at the Medical University of South Carolina, sees the threat of vaccine-evading mutations as possible, though not necessarily imminent, but either way, she agrees urgent action is needed to help prevent such a scenario.
“It is definitely within the realm of possibility that we can develop more mutations and that can have downstream effects on the vaccines,” Kuppalli tells me. “We need to double down on our public health measures now, and we need to quickly roll out the vaccines that we have.”
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Increased transmission can increase mutations
All viruses mutate, taking on or losing traits and characteristics. Most mutations are relatively meaningless until they’re not.
The mutated variant that originated in the U.K., called B.1.1.7 or B-117, allows the familiar spikes on the virus to bind more easily with receptors on human cells. It is thought to be about 50% more contagious than the current dominant strain, a figure supported by a growing number of infectious-disease experts based on ongoing research efforts into how rapidly the strain spread in England.
The emerging strain is in several U.S. states now, presumably at low levels, yet is likely to explode and overtake the other strain within a couple of months, by virtue of its infectiousness.
That puts humanity in a new and more urgent race against time, requiring an even greater commitment to hand-washing, masks, distancing, contact tracing, and other prevention tactics.
“It is definitely within the realm of possibility that we can develop more mutations and that can have downstream effects on the vaccines. We need to double down on our public health measures now.”
B-117 is not inherently deadlier, but because it spreads more easily, it will — if not stopped — ultimately kill more people than the original strain would have. Even if the new strain never evolves to evade the vaccine, its impact could be horrendous between now and the time when vaccinations have reached the vast majority of the population.
“Because B-117 can grow exponentially even in communities that are keeping SARS-CoV-2 under control, the situation is extremely urgent,” writes Harvard epidemiologist Marc Lipsitch, PhD, and a colleague in an analysis on Statnews. “If we want vaccination to win this new race, we have to slow down the new virus while it’s still rare.”
So far, the two most notable mutated strains — B-117 and 501.V2, which originated in South Africa — do not seem to sidestep vaccines or natural immunity.
Pfizer announced last week that a preliminary study finds its vaccine holds up against the B-117 mutations, noting that the nature of the vaccine’s construction should allow adjustments to meet the challenge of coronavirus mutations. But a Pfizer scientific officer told Statnews that vaccines will need to be tested against other mutations, which other scientists see emerging in various countries at an alarming rate.
Evading treatments is possible, too
Meanwhile, some coronavirus mutations detected in Europe last month appear to help the virus to hide from antibodies in drug cocktails produced by Regeneron and Eli Lilly for Covid treatments.
“The South Africa variant is very concerning right now because it does appear that it may obviate some of our medical countermeasures, particularly the antibody drugs,” Scott Gottlieb, MD, former head of the Food and Drug Administration, said last week. Scientists have also said this strain already has mutations with the potential to undermine vaccine effectiveness, but for now, they think it could be years before the ongoing evolution gets that far.
Still, concern is growing among many leading infectious-disease experts: The more infections that occur before the virus is constrained, the greater the risk of additional mutations that could evolve strains that don’t respond to existing treatments or are less affected by current vaccines.
Influenza is an example of a virus that evolves regularly, forcing constant development of new vaccines and fresh vaccinations annually.
“At present, we don’t have any evidence that there will be diminished efficacy of the available vaccines,” Bill Hanage, PhD, an associate professor of epidemiology at Harvard T.H. Chan School of Public Health, says in a statement. “The variant of concern reported in the U.K. does not appear more likely to reinfect those who we know were previously infected, which suggests vaccines will be effective.” The South African variant, he explains, “does have some mutations that have been reported elsewhere to evade elements of the immune response, but it is not clear whether its success is related to this or higher infectiousness.”
Complicating the outlook, immunity via vaccine or infection involves multiple aspects of the immune system and different types of immune cells, so it’s no easy task to sort out effects from the already increasing number of mutations, including in a new strain that just emerged in Japan by way of Brazil.
“It is important to note that vaccines work with multiple parts of the immune system, and so even if one is diminished, the others should still be active,” Hanage says.
Help is on the way, ever so slowly
Think of the two approved U.S. vaccines as a powerful cavalry that can indeed defeat the virus. Problem is, the cavalry is only trickling in. So far, only about 8 million Americans, or 2.4% of the population, have gotten a shot. Even if inoculations ramp up significantly in the coming weeks, as expected, it will be several months before enough people are immunized to halt viral momentum.
“The amounts of infections now are so high, and the comparative vaccination rates so low, that we have to be prepared for a coming surge into health care across the nation,” says Hanage. “It is already going to be bad enough. It might well be worse given the threat of more transmissible variants.”
The battle can still be won, Frieden and other health experts say, but only if policymakers and the citizens step up vigilance quickly and considerably, even as soaring infection numbers already portend higher daily death counts in weeks ahead.