- Delta is being dwarfed by Omicron right now, in the United States and in many places abroad.
- Delta-induced immunity doesn’t do a great job of protecting people from Omicron.
- the Delta lineage remaining in contention represents the most likely future.
While covid is still an ongoing pandemic around the globe coming along with different variants the delta and the omicron variant have a perplexed tussle going as to which variant is more dangerous to the human immune system, reports The Atlantic.
The tussle between omicron and the delta variant
In late November, Delta made up essentially all the SARS-CoV-2 infections that researchers were sequencing in the United States. Now it’s a measly 0.1 per cent.
The global portrait’s a bit patchier, but by and large, “Delta won’t be able to compete,” Karthik Gangavarapu, a computational biologist at UCLA, told me. “My suspicion is that Omicron will take over.”
As unlikely as it’s looking, a persistent, low-level Delta simmer—perhaps even a resurgence—is not off the table yet. Delta is still the Top Variant in some parts of the world.
Should it hold its own at any level, it will continue to pose a threat to us. After Omicron caught the world so off guard, “I would certainly not bet on Delta disappearing,” Lisa Gralinski, a coronavirologist at the University of North Carolina at Chapel Hill, told me.
To be clear, Delta is being dwarfed by Omicron right now, in the United States and in many places abroad. Although the older variant is clinging on for dear life in a few pockets, its grasp will likely continue to slacken and slip under the weight of its craftier cousin.
The main difference, Gangavarapu said, seems to be about how well each variant skirts some of the immune defenses laid down by vaccines and prior encounters with the virus; on this count, Delta’s an amateur, and the highly mutated Omicron is an A-list pro.
Our repertoire of shots is still staving off severe disease and death caused by any version of SARS-CoV-2. But the antibodies that reliably keep Delta from colonizing vaccinated hosts struggle to get a grip on Omicron, which means more people are vulnerable to infection with the newcomer.
Affecting the ones with the immunity
Omicron may also be reinforcing its own success. Delta-induced immunity doesn’t do a great job of protecting people from Omicron. But when Omicron infects people who have been vaccinated, it seems to shore up anti-Delta defenses too.
That might mean that the more immunized people Omicron infects, the fewer hospitable hosts Delta will have. The new variants we get from here on out could continue to follow this pattern, displacing the morphs that came before them year after year after year.
Then again, maybe not. That this competition is blatantly favouring Omicron so far does not necessarily tell us where Delta will end up. All infections are interactions between pathogen and host, which means Delta could hold its own, or make a comeback, for a bunch of reasons that aren’t just about the virus itself.
The longer Delta is able to bide its time, the more easily it might be able to engineer its own revival. As the world builds immunity to Omicron, the variant will have a harder time infecting new hosts; at the same time, the protective effects of vaccination and past infection that might have blocked Delta will wear off in people whom Omicron has not touched.
Transforming variants of covid
Even now, Delta has more than its fair share of opportunities to infect new people, replicate, and rejigger its genome. That is very much not what we want: Delta is thought to be the deadliest SARS-CoV-2 variant identified to date, and its descendants could very well preserve or even build upon its very lethal bite while picking up new tricks that bamboozle our immune systems.
Those modifications wouldn’t have to happen in humans, either. Delta could seek temporary asylum in another amenable animal species and tweak its appearance before jumping back into us. That’s actually one origin hypothesis for Omicron, which traces its roots back to a 2020 branch of the SARS-CoV-2 family tree.
In a “worst-case scenario,” Gostic said, Delta could transform into something capable of catching up with Omicron, and the two would tag-team.
Remaining constant or bidding adieu
The landscape for Delta is shifting by the day. Already, researchers are investigating an Omicron offshoot, BA.2, that’s surging in countries such as Denmark at surprising speed; too little is known to say anything for sure about how it changes Delta’s chances.
But they all remain possible, especially with a large fraction of the world’s population still unvaccinated, which means it’s worth preparing for them. We can’t guarantee what hijinks the virus will pull next.
Even if Delta does vanish in short order, its legacy won’t go poof quite as quickly. During its tenure, Delta has infected countless people around the world, leaving behind debilitating illnesses and death.
It is still tripping coronavirus tests. It is still filling hospital beds. It is still straining society’s capacity to care for the sick. A declining threat is not a nonexistent one. And until Delta is gone, truly gone, we’d be premature to bid it a full-throated adieu.
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Source: The Atlantic