AY.4.2 – The ‘Delta Plus’ variant – found in New York, California

  • AY.4.2, a daughter of the Delta variant, has been detected in New York and California.
  • Some evidence suggests that AY.4.2 may be slightly more transferable than Delta, but experts are not sure yet.
  • Studying Delta mutations could be a step towards variant-specific treatments.

A new version of the coronavirus – AY.4.2, sometimes known as “Delta Plus” – caught the attention of scientists when it began spreading in the UK in July. Now the variant has been discovered in New York and California, state health officials confirmed to Insider.

As of Friday, New York had confirmed five cases of AY.4.2, and California had detected two in the San Diego and San Francisco Counties.

The Centers for Disease Control and Prevention classifies the original Delta variant as a “variant of concern.” Delta causes more infections and spreads faster than previous forms of the virus, according to the CDC, and some data suggest it may cause more serious infection in unvaccinated people, although this has not yet been confirmed. As of October, Delta accounted for more than 99% of the sequenced cases in the United States.

AY.4.2 is a descendant of Delta, but the CDC does not classify sublineages separately.

In the UK, AY.4.2 accounted for 10% of the sequenced samples from Monday. It’s been steadily rising in the UK, “Jeffrey Barrett, Director of the COVID-19 Genomics Initiative at the Wellcome Sanger Institute, wrote on Twitter last week. This pattern is different from other sublineages of the Delta variant, none of which had a “consistent advantage” over other Delta types, he added.

Still, AY.4.2 replaces Delta in the UK at a much slower speed than Delta replaced the Alpha variant, which was previously dominant there, Barrett said.

Some evidence suggests that AY.4.2 may be slightly more transferable than AY.4, the most common Delta variant in the UK, but experts say more research is needed to know for sure. Jeremy Kamil, a virologist at Louisiana State University Health Shreveport, told STAT News that to prove that AY.4.2 is more transmissible, “you need to see the difference in multiple geographies,” and also observe that the trend “persists over a long period.”

Dr. Amesh Adalja, senior researcher at the Johns Hopkins Center for Health Safety, told Insider that the existence of a new variant does not necessarily give cause for concern.

“New varieties are being generated all the time,” he said. “That’s the normal thing this virus is going to do. It will continue to mutate. Although variants can gather headlines and people can write doomsday scenarios about them, most people will not really change the course of the pandemic.”

Given that the original Delta variant became dominant around the world, it is not surprising that we now see Delta mutations and daughter genera springing from it, Adalja added.

A COVID-19 monthly shot: variant-specific vaccines and treatments

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Nursing staff member Jen Madghachian receives her COVID-19 booster vaccination in Borehamwood, England, on October 4, 2021.

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The United States lags behind many nations in coronavirus sequencing. In the last six months, the United States has sequenced and shared results for only 6% of all positive tests, according to data from the Global Initiative on Sharing All Influenza Data. New York and California do more sequencing than most other parts of the United States, Nevan Krogan, a molecular biologist at the University of California, San Francisco, told Insider.

Given all this, it is likely that AY.4.2 is present in several states and cases just have not been discovered yet.

“If you look at where this virus is reported to be most prevalent, it’s in England. Why? It’s because they do better sequencing than anyone else in the world,” Krogan said.

But sequencing the virus is just the first step – researchers will then use this data to find out how the virus mutates and what these mutations mean.

“The jury is out as to what effects these mutations actually have on the virus. And do they give any extra power to the Delta variant?” said Krogan.

Answering this question will take considerable time and research, but doing so would help scientists get ahead of the virus – predicting which combinations will come into play, rather than reacting to variants after they emerge.

“The hope is that there is a limited amount of mutations that can happen with this virus,” Krogan said.

At best, he added, researchers could understand different variants well enough to develop variant-specific treatments or vaccines.

“It’s precision medicine,” he said.

Meanwhile, there is another way to slow the virus’ mutation rate: “The solution to the variants is the vaccine,” Adalja said, adding, “if people want to be less afraid of the variants, the solution is to have people vaccinated, so there are fewer variants in general. “

Dr. Catherine Schuster-Bruce contribute with reporting.

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