Call me a optimist!
@captainmorgan the great killer strain. We'll all be emergency boosted as the stops come out, the unvaxxed and unboosted will be dead or worse.
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Delta has shown how destructive new strains of COVID can get. Scientists fear future mutations of the virus could be even worse: "Delta on steroids."
www.newsweek.com
A Doomsday COVID Variant Worse Than Delta and Lambda May Be Coming, Scientists Say
Scientists keep underestimating the coronavirus. In the beginning of the pandemic, they said mutated versions of the virus wouldn't be much of a problem—until the more-infectious Alpha caused a spike in cases last fall. Then Beta made young people sicker and Gamma reinfected those who'd already recovered from COVID-19. Still, by March, as the winter surge in the U.S. receded, some epidemiologists were cautiously optimistic that the rapid vaccine rollout would soon tame the variants and cause the pandemic to wind down.
Delta has now shattered that optimism. This variant, first identified in India in December, spreads faster than any previous strain of SARS-CoV-2, as the COVID-19 virus is officially named. It is driving up infection rates in every state of the U.S., prompting the Centers for Disease Control and Prevention (
CDC) to once again recommend universal mask-wearing.
The Delta outbreak is going to get much worse, warns Michael Osterholm, an epidemiologist who leads the Center for Infectious Disease Research and Policy at the University of Minnesota. "The number of intensive-care beds needed could be higher than any time we've seen," he says. He adds that his team's analysis shows that almost every single one of the 100 million unvaccinated Americans who hasn't had COVID-19 yet will likely get it in the coming months, short of taking the sort of strong isolation and masking precautions that seem unlikely in the vaccine-hesitant population.
The variant is so contagious that it's set to smash through every previous prediction of how soon the U.S. might reach herd immunity. "We've failed to shut this down as we have other pandemics," says Jonathan Eisen, a biologist at the
University of California, Davis, who studies how pathogens evolve. "It may be around forevermore, leaving us continually trying to figure out what to do next."
Delta, like most of the other variants, blindsided us, worsening and extending the pandemic. When the damage from Delta starts to subside, what other variants will be lurking just behind it to pull us back down again? The World Health Organization is already keeping an eye on several: Eta, which is now in several countries; Kappa, which arose in India; Iota, which first popped up in New York City—and especially Lambda, which has torn through Peru and shows signs of having unusual success in infecting fully vaccinated people, according to one early study. It has already spread to Argentina, Chile, Ecuador as well as Texas and South Carolina.
It's too soon to say whether Lambda will turn out to be the next big, bad thing that COVID-19 unleashes on us. But it's a good time to wonder: Just how destructive can these variants get? Will future variants expand their attack from the lungs to the brain, the heart and other organs? Will they take a page from HIV and trick people into thinking they've recovered, only to make them sick later? Is there a Doomsday variant out there that shrugs off vaccines, spreads like wildfire and leaves more of its victims much sicker than anything we've yet seen?
The odds are not high that we will see such a triple threat, but experts can't rule it out. Delta has already shown how much worse things can get. Its extreme contagiousness, with room to run freely through the tens of millions of Americans who haven't been vaccinated and millions more who have no access to vaccines in developing countries, has good odds of turning into something even more troublesome. "The next variant," says Osterholm, "could be Delta on steroids."
Caught Off-Guard
It wasn't supposed to happen this way. Early in the pandemic, most experts closely studying COVID-19 mutations downplayed the notion that variants would cause such serious problems. "They don't seem to make much of a difference," said Richard Neher, an evolutionary biologist at Switzerland's University of Basel, in August last year. "We probably only need to worry about it on a timescale of about five years." Today he calls Delta and other COVID-19 variants "the pandemic within the pandemic."
Delta, more than any other variant, has reset scientists' understanding of how quickly a virus can evolve into devastating new forms. "All coronaviruses mutate, and we knew this one was mutating, too," says Sharone Green, a physician and infectious disease researcher at the University of Massachusetts Medical School. "But we didn't think the mutations would so strikingly affect transmissibility and possible evasion of immunity."
It may seem surprising that scientists were caught off-guard by the rapid emergence of a more dangerous variant. But unlike most other pathogens, Eisen notes SARS-CoV-2 was largely unknown when it emerged. In the absence of data, scientists assumed it would follow other viruses in being relatively slow to spin off much more contagious mutations. Even more important, he adds, scientists underestimated the sheer scale the pandemic would eventually achieve—a critical factor, because the more people a virus infects, the more opportunities it has to develop significant mutations. "Having billions of people infected presents a breeding ground for variants unlike anything we've ever seen with these sorts of viruses," he says.
SARS-CoV-2 doesn't mutate particularly quickly, compared to many pathogens. Just as with most human and other cells, a mutation occurs in a virus when it replicates but fails to make a perfect copy of its genetic material. That imperfect copy is a mutant. The COVID-19 virus doesn't have a lot of genetic material to scramble compared to most organisms—about 15 genes, versus about 3,000 genes in an E. coli bacterium, a run-of-the-mill stomach bug, and about 20,000 in a human cell. What's more, COVID-19 has genetic checking mechanisms that make it reasonably adept at avoiding replication mistakes compared to most viruses.
But while COVID-19's mutation rate is on the low side—about one mutation for every 10 replications, or around a fifth of the flu's mutation rate and a tenth of HIV's—COVID-19 takes advantage of a grim numbers game. A single person infected with COVID-19 might carry 10 billion copies of the virus, enough to produce billions of mutated viruses every day. What happens to all those mutations? Almost always the answer is: nothing. The genetic scrambling is random, with the result that virtually all mutations either have no effect whatsoever on the virus, or else do something that makes the virus less effective or even renders it entirely non-functional.
But once in a while—perhaps every million trillion times—a random mutation confers some potentially dangerous new characteristic. What's more, much of what makes the virus dangerous has to do with a relatively small portion—the so-called spike proteins that protrude from its surface and enable the virus to latch onto and penetrate human cells. Most of the mutations we've seen so far represent tweaks to these spikes, which means it only takes a minimal change within any of the few viral genes that control the spikes to create a newly threatening mutation.
But even when a virus hits the jackpot with a mutation that sharpens its ability to wreak havoc, that doesn't mean a dangerous new variant has emerged. To become a significant variant, a mutated virus has to out-replicate the far more numerous copies of the virus that already predominate in the population, and to do that it needs features that give it big advantages.
What specific features will help the mutation become a better replicator and spreader in the population is determined by the environment. For example, in the case of a respiratory virus like COVID-19, the ability to travel longer distances in the air, and to latch more firmly onto cells in the nasal passage, would likely make a new strain a better contender to become a widely spreading variant.
"A virus' job is just to keep propagating," says Green. "Any mutation that helps the virus survive and spread will make it more successful as a variant."
All told, the chances that a virus in the population will produce a much more dangerous variant in the course of a year would normally be extremely low. But when billions of people are infected with billions of copies of a virus, all bets are off. Thanks to Delta's infectiousness, and the huge number of people whose refusal or inability to get vaccinated leaves them primed to become living COVID-19 mutation labs, the conditions are ripe to produce yet more, potentially more dangerous, variants in the coming months.
"It's going to be very difficult to stop it from happening with masks and social distancing at this point," says Preeti Malani, a physician and infectious disease researcher and chief health officer at the University of Michigan. "Vaccines are the key, and vaccine hesitancy is the obstacle."
The growing number of people with natural immunity, from having recovered from COVID-19, won't save the day either, says Eric Vail, director of molecular pathology at Cedars-Sinai Medical Center. "At best it's now a third of the U.S. population with natural immunity, and that may be an overestimation," he says. "It won't be enough to guarantee that Delta will be the last big variant."
thehill.com
