According to Eric Feigl-Ding, the new variant is more immune evasive and better at infecting than BQ and XBB. He said multiple models shows that XXB15 variant is much worse in transmission R value and infection rate than previous variants.
"Ironically, probably the worst variant that the world is facing right now is actually XBB," said Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, in an interview with Reuters.
Covid-19: What is XXB.1.5 variant?
XXB.1.5 is a sub-variant of coronavirus infection that is responsible for over 40% of cases in the United States. Multiple models show that XXB.1.5 is much worse in transmission R value and infection rate than previous variants, said Eric Feigl-Ding.
In simple words, XBB and XBB.1.5 both are the recombinants of the BA.2 variant. According to Virologist G Kang, XXB is like all Omicron subvariants that has very good at infecting people because they escape the immune response that prevents infection, but are not causing more severe disease than delta.
The data shows that XBB15 was 108% faster than the previously king BQ1 variant. But with more data, XBB15 has further accelerated to now being 120% faster, he added.
The epidemiologist stated that XXB.1.5 is likely an American-originated recombination variant that is 96% faster (worse) than old XBB. The XBB15 popped up in the New York area in October and been causing trouble since.
“New York has been suffering the largest Covid-19 hospitalization 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," he added.
How XXB.1.5 is different from other variants?
The health expert also explained the key factors that differentiate XBB15 from other omicron variants are:
- One of the most immunity-evasive variants to date,
- One of the best variants for entry and invading human cells,
- Appears to spread much faster than old XBB or BQ, and
- Causes hospitalizations wherever it’s dominant.
What are the symptoms of XXB and its sub lineages?
XBB and its sub lineages account for 56% of the Covid cases in the country. Key symptoms related to the variant are runny nose, sore throat, fever, headache, sneezing, cold, cough, and hoarse voice.
Will available Covid vaccines work?
Answering this, Eric said, many people asking if the older Wuhan 1.0 or Bivalent Omicron vaccines will still work.
“I say that the bivalent BA5 (used in the US) & bivalent BA1 (used in the UK) likely have some efficacy. But unclear how much because XBB15 is a special recombination of BA2 strains—don’t know."
On the other hand, G Kang said, “Who needs boosters? Booster doses on any platform are likely to have an incremental benefit in anyone, at least for a while. Among vaccines in India, all vaccines fine, but order based on immune response will be protein, adenovirus vectored, inactivated."
Over 40% of US Covid cases caused by XXB.1.5 variant
The XBB and XBB.1.5, together accounted for 44.1% of the total cases in the country for the week ended December 31. For the week ended December 24, XBB.1.5 had made up 21.7% of the total cases, as per Reuters reports.
John Moore, a professor of microbiology and immunology at Weill Cornell Medical College in New York said, “Every previous two winters, we have seen a surge of infections that peaked in mid January... and I expect the same to happen this year."
He added that the difference between last two years and this year is that there has not been a significant increase in the death rates.
The XBB variant has been driving up cases in parts of Asia, including Singapore. It accounted for 3.6% of the total cases in the U.S. this week compared with 4.2% in the previous week. The agency began reporting data for the two subvariants separately from this week.
Covid: India reports first case of XXB.1.5 variant
India has reported its first case of Omicron variant ‘XXB.1.5’ which is responsible for the surge in coronavirus cases in New York. The first case of XXB.1.5 has been confirmed in Gujarat, as per ET reports. The country already has XBB and BF.7 cases.
G Kang stated that India is doing fine at the moment. “We have few cases, we have had the XBB and BF.7 for a while and they have not driven an upsurge in India. In the absence of an even more highly infectious variant, I do not expect a surge," the health expert said.
(With inputs from agencies)
