A new Omicron sub-variant is gaining traction in the US, according to the Centers for Disease Control and Prevention.
BA.2.12.1, an offshoot of the BA.2 Omicron “stealth” variant, now accounts for around one in five new Covid cases across the country.
Together, BA.2 and BA.2.12.1 are estimated to make up more than 90 per cent of the coronavirus variants nationwide, as of April 16.
“BA.2.12.1 has increased rapidly in proportion in the US compared to other BA.2 sublineages,” especially in the area around New York and New Jersey, a CDC spokesperson told CNN.
Last week, New York state health officials raised the alarm about two new sub-variants, including BA.2.12.1, saying they had an estimated 23 per cent to 27 per cent growth advantage above the original BA.2 variant.
Officials said they were suspected to be behind the drive in rising cases in the area. However, they added there is “no evidence of increased disease severity” as a result of the Omicron off-shoots.
“Another new strain that appears to be even more transmissible than the last and that would explain at least some of the rise in cases we are starting to see, though I think we would have seen one even without this,” Matthew Fox, a Boston University School of Public Health epidemiology professor told the Boston Herald.
“The good news is that it does not appear to be more severe than any of the last omicron variants — at least so far — and so we are really looking at more cases, but hopefully not a sharp increase in hospitalizations and deaths.
“We will have to keep our eye on it.”
According to data from GISAID, which collates Covid data, samples of the sub-variant have been found in seven other countries, including the UK.
As of Wednesday, at least four cases of BA.2.12.1 had been sequenced in the UK.
Cases have also been sequenced in Australia, Austria, Canada, Denmark, Israel and Luxembourg.
The news of the sub-variant comes as the Biden administration moved to appeal a court order which struck down a federal mask mandate which required their use in planes, trains and other public transport.
In a statement early Thursday morning, the CDC said it recommended that people wear masks in all indoor public transport settings amid the appeal.
