EXPLAINS: What is known about the ‘stealth’ version of omicron? | Health

This version of the coronavirus, which scientists call BA.2, is widely considered to be more insidious than the original version of the omicron because specific genetic traits make it somewhat more difficult to detect. Some researchers are concerned that it may also be more contagious.

But they say there is a lot they still do not know about it, including whether it avoids vaccines better or causes more serious illness.

Since mid-November, more than three dozen countries have uploaded nearly 15,000 genetic sequences of BA.2 to GISAID, a global platform for sharing coronavirus data. As of Tuesday morning, 96 of these sequenced cases came from the United States

“So far, we have not seen it start gaining ground” in the United States, said Dr. Wesley Long, a pathologist at the Houston Methodist in Texas, who has identified three cases of BA.2.

The mutant is much more common in Asia and Europe. In Denmark, it accounted for 45% of all COVID-19 cases in mid-January against 20% two weeks earlier, according to the Statens Serum Institut, which is part of the Ministry of Health.

WHAT IS KNOWN ABOUT THIS VERSION OF THE VIRUS?

BA.2 has lots of mutations. About 20 of those in the tip protein that bounce off the outside of the virus are shared with the original omicron. But it also has additional genetic changes not seen in the original version.

It is unclear how significant these mutations are, especially in a population that has encountered the original omicron, said Dr. Jeremy Luban, a virologist at the University of Massachusetts Medical School.

So far, the original version, known as BA.1, and BA.2 are considered as subsets of omicron. But global health executives could give it its own Greek letter name if it is considered a globally significant “variant of concern.”

The rapid spread of BA.2 in some places raises concerns that it may gain momentum.

“We have some indications that it may just be just as contagious or maybe a little more contagious than (original) omicron, as it is able to compete with it in some areas,” Long said. “But we do not necessarily know why that is.”

An initial analysis carried out by researchers in Denmark shows no differences in admissions for BA.2 compared to the original omicron. Researchers are still investigating the infectivity of this version and how well the current vaccines work against it. It is also unclear how well treatments will work against it.

Doctors do not yet know for sure whether a person who has already had COVID-19 caused by omicron can get sick again from BA.2. But they are hopeful, especially that a previous omicron infection may reduce the severity of the disease if someone later gets BA.2.

The two versions of omicron have enough in common that it is possible that infection with the original mutant “will give you cross-protection against BA.2,” said Dr. Daniel Kuritzkes, an infectious disease expert at Brigham and Women’s Hospital.

Researchers will perform tests to see if antibodies from an infection with the original omicron “are able to neutralize BA.2 in the laboratory and then extrapolate from there,” he said.

HOW CONCERNED ARE HEALTH ORGANS?

The World Health Organization generally classifies omicron as a variant of concern, its most serious term for a coronavirus mutant, but it does not exclude BA.2 by its own term. However, given its increase in some countries, the Agency says that studies on BA.2 “should be a priority.”

The UK Health Safety Agency has meanwhile designated BA.2 as a “variant under investigation”, citing rising figures found in the UK and internationally. Yet the original version of omicron is still dominant in the UK

WHY IS IT HARD TO SET UP?

The original version of the omicron had specific genetic characteristics that allowed the health authorities to quickly differentiate it from the delta using a specific PCR test due to what is known as “S-gene target failure.”

BA.2 does not have the same genetic trait. So on the test, Long said, it looks like BA.2 delta.

“It’s not because the test does not detect it; it’s just that it does not look like omicron, ”he said. “Do not get the impression that ‘stealth omicron’ means we can not detect it. All our PCR tests can still detect it.”

WHAT SHOULD YOU DO TO PROTECT YOURSELF?

Doctors advise the same precautions they always have: Get vaccinated and follow the public health guidelines for wearing masks, avoiding crowds and staying home when you are sick.

“The vaccines still provide a good defense against serious illness, hospitalization and death,” Long said. “Even if you’ve had COVID 19 before – you’ve had a natural infection – the protection against the vaccine is still stronger, longer lasting and actually … does good for people who have been infected in the past.”

The latest version is another reminder that the pandemic is not over.

“We would all wish it was over,” Long said, “but until we get the world vaccinated, we will be at risk of getting new varieties popping up.”

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. AP is solely responsible for all content.