If you’ve been worried by recent news stories about a strain of covid called “delta plus,” it may freak you out to hear that scientists just expanded the delta family from four variants to 13.
Please take a deep breathe. Scientists want you to realize that there is no evidence that delta has learned new tricks. These new names are used to track covid’s evolution and not nine reasons to panic. Many researchers hope you will stop calling “delta plus”
” The name ‘delta’ is incorrect because it creates the impression that more damage will be done,” says Anderson Brito of the Pango Lineage Designation Committee. This committee assigns scientific names such as B.1.1.7 to new viruses. “So far, there is no evidence that any mutations have affected behavior in comparison to the original Delta variant
. It might help to think of covid like a tree. Delta is like a large branch of a tree. It’s a family of viruses that shares a common ancestor, some of the same mutations and allows them to spread more quickly between people. Scientists use numbers and letters to keep track of the new branches that grow, which is something that happens every day. However, a new scientific name does not mean that the viruses will behave differently than the branch from which they were born. If one of these new branches starts to change its behavior, it is given a new Greek letter.
Now is a good moment to remind everyone that although some of delta’s mutations make them more transmissible vaccines can still prevent severe illness from any known strain of covid. )
What’s in a name, you ask?
This confusion in naming results mainly from the way that journalists (and their scientists sources) have combined two widely used systems for tracking the evolution of covids, despite the fact they have different strategies and goals.
The alphanumeric system which gave the first variant of the delta its scientific name,–B.1. 617.2–is called Pango. This is for researchers to track small genetic variations in the virus. It does not determine if new lineages behave differently in humans, but it does indicate whether they are different at a molecular level. There are currently over 1,300 Pango lineages, 13 of which are considered part of the delta family.
The name delta, meanwhile, comes from the WHO system, which is meant to simplify genomics for the general public. If it thinks they might be of particular value, it names related covid samples. The WHO currently considers all eight families that have Greek letters to be the delta. However, until evidence is presented that a new sublineage or subgroup of the first strain is acting differently than its parents, there are only eight families with Greek letters.
Delta Plus” takes Pango’s lineage information and mixes it with the WHO designation. This doesn’t necessarily mean that the virus is more serious or more dangerous.
People get anxious when they see a new Pango number. We shouldn’t be worried about the discovery of new Pango variants. Brito says that we are seeing new variants with the same behavior all the time. “If we have evidence a new lineage is more threatening, WHO will give it a new name.”
“For a genomic scientist like me, I want to know what variations we’re seeing,” says Kelsey Florek, senior genomics and data scientist for the Wisconsin state public health lab. It doesn’t make any difference to the public. It is enough to classify them all as “delta” for communication with policy makers, public
Fundamentally viral evolution works the same way as any other type. The virus spreads throughout the body and makes copies, often with small errors or changes. While most of these copies are not useful, it can sometimes replicate enough within a person to spread the virus to others.
As the virus spreads from person to person, it accumulates those small changes, allowing scientists to follow patterns of transmission–the same way we can look at human genomes and identify which people are related. Most of these genetic changes do not have an impact on how the virus affects people and communities.
Genomic researchers still need to be able to track the viral evolution for both basic science and to detect any behavioral changes as soon as possible. They are monitoring the rapid spread of viral evolution in delta and keeping an eye on its patterns. Pango continues to divide descendants of the original delta lineage, B.1. 617.2, into subcategories of related cases.
Until recently, it had registered 617.2 itself plus three “children,” called AY.1, AY.2, and AY.3. This week, the team decided to split those children into 12 families in order to better track small-scale local changes–hence the total of 13 delta variants. This does not mean that the virus has suddenly changed.
” Particularly at the margins with these emerging variants of the virus, you are splitting hairs,” Duncan MacCannell (CDC’s Office of Advanced Molecular Detection) says. “How those definitions have been crafted and refined can affect the way hairs split .”
What matters to the public?”
It’s important to note that not all variants of WHO nicknames are equally harmful. The label that tells us how concerned we should be is added to the name of a new family when it gives it a name.
The lowest level is a variant ,, which is something to watch out for. In the middle is a variant of concern like Delta, which clearly has evolved to be more hazardous. Variants of interest often share a mutation with variants that are of concern, so they’re under surveillance.
The CDC has an additional, more severe category, a variant of high consequence, which has never been given to a family of covid. It is reserved for future strains that could cause serious illness in people who have been vaccinated.
The two Pango lineages most commonly called “delta plus”, AY.1 or AY.2, have a mutation previously found in another variant of concern, known as beta, that first appeared in South Africa. However, in the many months since AY.1 was discovered, there have been no signs that they have changed from their parents in terms of how they behave.
We identify mutations we believe have significance and there’s evidence to support that,” MacCannell says. “Sometimes they pan out, but sometimes they don’t.”
So if they behave no differently, then why do many public health agencies, including the CDC, split out the sublineage for delta cases when reporting their figures?
A lot of it is to avoid questions. We can put up a ticker saying “Delta has these many cases,” and we get questions such as “Do we have any AY.3?” Florek, the creator of Wisconsin’s covid sequence dashboard, said, “I’ve heard that AY.3 can be concerning.” It’s not only the media. It’s all the customers we serve as state public health laboratories.
” What is the best way to approach this problem? I don’t know. I think we’re all kind of learning the best way to communicate the necessary information, in a way that’s actionable and interpretable by a large audience.”
Scientists will always have educated guesses about which genes are linked to changes in behavior. However, this speculation is often based upon lab experiments that examine the effects of individual genetic mutations.
In reality, mutations occur randomly in the viruses’ genomes in millions of people infected. Some mutations are eliminated, while others spread to other people. As the mutations accumulate, they interact with each other and with human actions in complex ways that can lead to real-world behavior.
It takes scientists a long time to research and understand the situation. This is much longer than what it takes to write a news article or publish a paper online with no peer review.
Genomics is only the beginning of the story. Brito says that it tells us this variant exists. “We can be anxious when there’s a reason, but not for minor changes.”
This story is part of the Pandemic Technology Project, supported by the Rockefeller Foundation.
https://www.technologyreview.com/2021/08/13/1031844/delta-plus-covid-variant-naming/, Technology Review