A new ‘worst variant’ Covid strain dubbed XBB.1.5 is rapidly spreading in US

Experts fear that the new Omicron subvariant will cause another avalanche of Covid-19 cases. Here is what you need to know.

Experts have warned that the new Omicron variant spreading rapidly in the US is the “next big one” as concerns are raised about another potential wave of Covid cases following the busy holiday travel season.

The strain, known XBB. 1.5, was first reported in mid-November and has now overtaken the BQ. 1 and BQ. 1.1 variants.

Harvard-trained US epidemiologist Eric Feigl-Ding warned that the so-called “super variant” was “among most immunity-evasive ‘escape variants’ to date” and that it was “one of the best variants for invading human cell”.

He said not only does it “spread much faster” than older strains, but slammed the Centre of Disease and Control for “royally screwing up” by failing to warn people of the danger for weeks on end.

“Hospitalisations [are] already approaching last winter’s crazy Omicron levels. These numbers do not include Veterans Affairs hospitals – and it’s missing several states. So it could be worse,” he posted on Twitter .

📝Recap why #XBB15 (storming 🇺🇸&🇬🇧) is a super variant:

📍among most immunity-evasive ‘escape variants’ to date

📍one of the best variants for invading human cells via ACE2.

📍Spreads much faster than old XBB or BQ

📍Causes ⬆️hospitalizations wherever dominant (NY CT MA NJ)🧵 pic.twitter.com/n655wzvEHw

— Eric Feigl-Ding (@DrEricDing) December 31, 2022

“We aren’t ringing the alarm bells of the new XBB15 wave enough. Wastewater SARS-CoV-2 now at a HIGHER level nationwide than even spring 2020 wave or the Alpha wave of winter 2020-2021. Only second to initial Omicron winter 2021-2022. But it’s still climbing.

“New York has been suffering the largest Covid-19 hospitalisation in almost a year. And it’s not coming down quickly like in recent waves Omicron waves. “That’s because XBB15 is not your typical Omicron – it’s a special recombination mixture variant that is further mutated.”

Dr Feigl-Ding also hit out at the decision by a string of nations – including Australia – to introduce new restrictions for Chinese travellers, claiming the threat posed by XBB15 was far worse, despite China’s current Covid crisis.

“XBB15 first emerged in New York of anywhere in the world. Talks of travel bans against China/testing only (Chinese people) is discriminatory – XBB15 is the worst variant of the world right now. In fact, it’s a US variant,” he said.

It comes after Australia’s Health Minister Mark Butler announced on New Year’s Day that mandatory pre-departure testing for travellers from China will begin from 12.01am on January 5, requiring a negative test within 48 hours.

And while there’s a lot that’s still unknown about the latest subvariant, including whether it’s more contagious than other forms of omicron, this is what we know so far.

WHAT WE KNOW

The XBB. 1.5 is a relative of the omicron XBB variant, which is a recombinant of the omicron BA. 2.10.1 and BA. 2.75 subvariants.

The strain is responsible for nearly 41 per cent of confirmed Covid cases in the US as of December 31, which is up by about 20 per cent from the previous week.

However, it’s not clear yet where this version of omicron came from but it appears to be spreading quickly here.

Picture: AFP.

Director of CDC’s coronavirus and Other Respiratory Viruses Division Dr Barbara Mahon told NBC News that there’s no indication yet it causes more severe illness than any other omicron virus.

“We’re seeing hospitalisation have been notching up overall across the country,” Dr Mahon said.

“They don’t appear to be notching up more in the areas that have more XBB. 1.5.”

WHAT ARE THE SYMPTOMS?

There do not appear to be any additional Covid-19 symptoms tied to XBB. 1.5 that are different from normal symptoms.

However, scientists worry that XB. 1.5 is even better at getting around the antibodies we’ve built up from Covid vaccines and previous infection from the many different types of omicron that have spread.

WHERE HAS IT BEEN FOUND?

The new variant has been found in at least 70 countries, according to the World Health Organisation, and has caused surges of infection in some parts of Asia, including India and Singapore, in October.

Studies performed in the lab have found that XBB is capable of evading antibodies from previous Covid infections or vaccinations.

This means that being exposed to the virus would make someone more likely to get sick or reinfected and show symptoms.

The variant has been detected in at least 70 countries. Picture: AFP.

“It’s clear that there’s immune evasive properties of XBB,” infectious disease physician and epidemiologist at the University of Toronto Dr. Isaach Bogoch told NBC.

“That’s been demonstrated both in laboratory studies and seen clinically in cases and hospitalisation.”

“We might certainly have a wave, but it’s just much less likely to be as deadly or overwhelming to a health care system compared to earlier waves before we had this degree of hybrid immunity.”

DO COVID VACCINES WORK AGAINST XBB. 1.5?

American immunologist and former director of Biomedical Advanced Research and Development Authority, or BARDA, Rick Bright said there are encouraging signs as seen in Singapore’s experience with XBB.

“There was a surge of cases, but we didn’t see the corresponding major surges in hospitalisation and deaths,” he told NBC.

“We think it is because a larger population of people in Singapore have been vaccinated with the latest vaccines and boosters.”

A health worker takes a swab from a passenger of a flight from China at the Covid-19 testing booths. Picture: AFP.

Health experts agree that getting the new booster — called a bivalent because it targets the omicron strains BA. 4 and BA. 5 as well as the original coronavirus — will bolster your immune system against the newer subvariants.

“We aren’t in 2020, but people still do need to take this seriously and protect themselves,” Dr Mahon said.