How worried should we be about the “delta plus” variant?


The delta sub-variant known as AY.4.2 – worryingly dubbed ‘delta plus’ – is making headlines as cases increase in the UK.

Earlier this month, the UK’s Health Security Agency released a report indicating that “a delta subline newly referred to as AY.4.2 is developing in England.” The descendant of the highly transmissible delta variant has two spike protein mutations, and it appears to be on “an increasing trajectory” as the most recent data suggests it accounted for around 6% of all cases sequenced in the UK

So what does this mean for the United States?

First of all, the variant of the delta subtype has already been detected on our coasts. However, the Centers for Disease Control and Prevention (CDC) recently said delta plus was not a cause for concern. . . yet, but the agency is monitoring the situation closely.

READ MORE: Delta variant twice as likely to hospitalize victims, new study finds

“We are watching it very carefully,” CDC director Rochelle Walensk Walensky told NBC’s Meet the Press last week. “We’ve had a handful of cases here in the US, but it hasn’t taken off like in the UK”

As some may recall, before the Delta variant exploded in the United States, it was the dominant strain in the United Kingdom. In many ways, UK countries have become role models for the US, which is why the news about the increase in the “delta plus” variant overseas can be baffling to Americans. Does this mean that a delta-plus wave is imminent?

Experts who have tracked the pandemic tell Salon it likely won’t be any worse than the original delta surge, but it’s a variant to watch because AY.4.2 may be more transmissible than the current dominant delta variant. .

“Any variation is potentially a cause for concern, and given what has happened with delta, I would be very hesitant to say that anything is absolutely not a problem, especially since we know little about it.” Justin Lessler, professor in the epidemiology department at the Gillings School of Global Public Health at the University of North Carolina, said Salon. “But that being said, what we know about the Delta Plus variant doesn’t tell me it’s a major problem, at least for the United States.

“It appears to be about 10% more transmissible than delta,” he continued, “and in our work on the Scenario Modeling Center, when we looked at a hypothetical variant that was 50% more transmissible than delta, we’ve seen resurgences in this case, but we haven’t seen big ones that get us back to the size of the delta wave or the winter wave of last winter. “

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Indeed, Lessler is part of the COVID-19 Scenario Modeling Hub coordination team that modeled a series of projections based on different scenarios; one being an emerging more transmissible delta variant. But as Lessler noted, the “delta plus” variant in question is estimated to be only 10% more transmissible, which many say is not enough to cause another major wave.

Monica Gandhi, an infectious disease physician and professor of medicine at the University of California, San Francisco, told Salon that the delta variant will mutate. This is to be expected, but the only reason all eyes are on AY.4.2 is that it appears to be slightly more heritable.

“The problem with the delta variant is that we have other variants that come and go, like mu and lambda, and it’s the only one we see just because it couldn’t be more transmissible, none of others was no longer heritable, “Gandhi said.” So I think it is the right thing to do, to watch, but I will tell you that there is simply no evidence that it beats vaccines, which is, of course, the scariest thing that can happen from a variant. “

Gandhi has said that delta plus can still infect people who have the delta variant or have been vaccinated, but there is no evidence that the symptoms it causes will be more severe.

“It can definitely get into your nose, but that doesn’t mean you’re even sicker from it,” Gandhi said. “If it’s more noticeable, like 10%, it can go in your nose, you can detect it, you can have an asymptomatic infection, but if we haven’t seen people get sicker from it.”

Gandhi added that the United States is in a better position to deal with a delta surge today than it was in early July when the delta variant took off here because now more people are being vaccinated. Gandhi pointed to a modeling study published in the Annals of Internal Medicine that estimated population immunity in the United States was estimated at 62% in early July before the delta surge. Today, this percentage is higher.

“With 34 million new injections and probably over 30 million new infections, we could reach over 85% seroprevalence now,” Gandhi said in a follow-up email to Salon. “With over 80% or even 90% to control the delta, we may be approaching that level now. “

Since the delta variant searches for unvaccinated individuals, there will be fewer people to infect for a subtype variant like delta plus.

What scientists know about this variant is that it has two spike protein mutations, which may better help it invade its host’s cells. Still, many uncertainties about Delta Plus remain.

“These are the mutations that have been pointed out by researchers as potentially interesting mutations to look at, but it remains to be seen what role they play in terms of the type of behavior of AY.4.2,” said Sasan Amini, Founder and CEO from Clear Labs, a private genomics company. “It remains to be seen what these mutations actually do.”

Amini added that it is notable that AY.4.2 was first identified in the UK in April 2020, as data from the confirms.

“And it’s not yet a dominant variant, compared to the delta variant, but it’s increased,” Amini said. “Some of this faster growth could be attributed to some of the mutations that AY.4.2 has actually built up over time, and so we should always factor in those specific evolution times in the setup, so definitely the track record. of the UK variant it’s interesting for us to observe, but it is too early to say that this will become a key variant that concerns us. ”

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