A new strain of coronavirus surging through California is more infectious and at least partially more resistant to vaccines, scientists have warned.
The US state has seen a rise in cases and deaths in recent weeks which is now being attributed in part to the variant.
Researchers at UC San Francisco say that it should be marked as a “variant of concern”, like the UK strain.
The LA Times reports that the California variant will probably account for 90 per cent of the state’s infections by next month.
Previously, much concern has been directed towards the arrival of the B.1.1.7 strain from the UK.
What do you think of this story? Let us know in our comments section
But Charles Chiu, an infectious diseases researcher and physician at the university, has now warned: “The devil is already here.”
Studies found that the variant probably first emerged in May but has now become dominant.
Named B.1.427/B.1.429, experts say it spreads more readily and can, at least partially, evade antibodies generated by vaccines or prior infection.
In lab studies, it was found to be four times less susceptible than the original coronavirus to neutralizing antibodies from the blood of Covid patients.
And it was twice as likely to not be susceptible antibodies in the blood of people vaccinated with either the Pfizer or Moderna jabs.
The UC San Francisco researchers said the diminished potency is “moderate but significant”.
It is also associated with severe illness and death, the city newspaper reports.
Mr Chiu added that both the UK and California variants are each armed with enhanced capabilities.
This presents a likelihood that they could circulate in the same population – possible leading to a spike in infections and deaths.
Dr. Anthony Fauci, the top infectious diseases expert in the US, also raised a further concern in an interview with the LA Times.
He said a contest between the two variants could quicken the spread of the strain that is best able to elude the effects of vaccines.
And he urged people to try and stop the spread of coronavirus, adding: “If viruses don’t replicate, they don’t mutate.”
Coronavirus deaths in the US recently passed the 500,000 mark.
President Joe Biden said in an address that people should “remember those we lost and remember those we left behind”.
He added: “As a nation, we can’t accept such a cruel fate. We have to resist becoming numb to the sorrow.”
Strains originating in Brazil and South Africa are also causing concern for scientists across the world.