What is Covid’s new variant XBB.1.5, responsible for over 40% of US cases?

Data from the US Centers for Disease Control and Prevention has confirmed that over 40% of Covid-19 cases in the United States are now caused by Omicron XBB.1.5 — a variant which has concerned experts.

“Ironically, probably the worst variant that the world is facing right now is actually XBB,” Dr Michael Osterholm, an infectious disease expert at the University of Minnesota, told Reuters.

Here is all you need to know about XBB.1.5

1. Virologist Eric Feigl Ding called XBB.1.5 a ‘super variant’, the ‘next big one’, which is causing a surge in hospitalisation in New York.

2. XBB.1.5 is a new recombinant strain and is both more immune-evasive and better at infecting than BQ.1 and XBB, the virologist said adding that it is not ‘typical Omircon’, but a special recombination mixture variant that is further mutated.

3. The R-value of XBB.1.5 is much worse than the previous variants. “Multiple models show XBB.1.5 is much worse in transmission R-value and infection rate than previous variants — faster by LEAPS and BOUNDS,” Eric Fiegl Ding tweeted.

4. According to data, XBB.1.5 is 120% faster than BQ.1

5. “XBB.1.5 is likely an American-originated recombination variant that is 96% faster (worse) than old XBB. The XBB.1.5 popped up in the New York area in October and has been causing trouble,” the virologist tweeted.

6. All US states where XBB.1.5 is dominant are witnessing a surge in hospitalisation leading to the explanation that this variant is behind the increased rate of hospitalisation.

7. In the UK too, XBB.1.5 is spreading fast.