Reports from the UK and South Africa about new coronavirus strains appearing to spread more easily are causing concern, but virus experts say they are unlikely to undermine vaccine immunity.
Viruses develop naturally as they move through the population, some more than others. That’s one reason we need a new flu shot every year.
New variants or strains of the virus that causes Covid-19 have been seen almost since it was discovered in China almost a year ago.
On Saturday, Prime Minister Boris Johnson announced new restrictions due to the new strain. Several EU countries and Canada are banning or restricting travel from the UK to try to limit the spread.
Here is what is known about the situation.
Why does a new load raise an alarm?
Health experts in the UK and US said the strain appears to be more easily transmitted than others, but there is no evidence yet that it is more deadly.
Patrick Vallance, the UK Government’s leading scientific adviser, said the strain was “moving fast and becoming the dominant variety”, causing over 60% of infections in London in December.
MK LHL test data showing increasing prevalence of the H69 / V70 variant in positive test data – which is otherwise detected by the standard 3-gene PCR test. pic.twitter.com/1U0pVR9Bhs
– Tony Cox (@The_Soup_Dragon) December 19, 2020
The strain is also worrying because it has so many mutations – almost two dozen – and some are on the prickly protein that the virus uses to attach to and infect cells. That nail is what current vaccines are aimed at.
“I’m sure of this,” but it’s too early to know how important it will ultimately prove to be, says Dr. Ravi Gupta, who studies viruses at the University of Cambridge in England.
Gupta and other researchers published a report on it on a website that researchers use to quickly share developments, but the journal has not been formally reviewed or published in a journal.
How do new strains arise?
Viruses often get small changes of a letter or two in their genetic alphabet just through normal development. A slightly modified strain may become the most common in a country or region simply because it is the strain that first grabbed there or because “super spreader” events helped it to anchor itself.
A major concern is when a virus mutates by altering the proteins on its surface to help it escape from drugs or the immune system.
“Emerging evidence” suggests that it may start to happen with the new coronavirus, wrote Trevor Bedford, a biologist and genetics expert at the Fred Hutchinson Cancer Research Center in Seattle, on Twitter.
“We have now seen the emergence and spread of several variants,” suggesting this, and some show resistance to antibody treatments, he noted.
We have now seen the emergence and spread of several variants that may have a certain antigenic effect. These variants are usually labeled based on the mutation to the SARS-CoV-2 nail protein. For example, N439K has a change from asparagine (N) to lysine (K) at position 439 in nails. 9/18
– Trevor Bedford (@trvrb) December 19, 2020
What other tribes have appeared?
In April, researchers in Sweden found a virus with two genetic changes that seemed to make it about twice as contagious, says Gupta. About 6,000 cases worldwide have been reported, mostly in Denmark and England, he said.
Several variations of that strain have now emerged. Some were reported in people who got them from mink farms in Denmark. A new South African tribe has the two changes we have seen before, plus some others.
The one in the UK has the two changes and more, including eight to the nail protein, Gupta said. It is called a “variant under investigation” because its meaning is not yet known.
The tribe was identified in the south-east of England in September and has been circulating in the area since then, a World Health Organization official told the BBC on Sunday.
Will new strains undermine vaccines?
Elected President Joe Biden’s nominated surgeon, Vivek Murthy, said on Sunday on NBC’s “Meet the Press” that there is “no reason to believe that the vaccines that have been developed will not be effective against this virus as well.”
Vaccines produce widespread reactions from the immune system beyond just those against the nail protein, several experts noted.
The possibility that new strains will be resistant to existing vaccines is low, but not “non-existent”, said Dr. Moncef Slaoui, the scientific adviser to the U.S. government’s vaccination distribution, on Sunday on CNN’s “State of the Union.”
“So far, I do not think there has been a single variant that would be resistant,” he said. “This particular variant in the UK, I think, is very unlikely to have escaped vaccine immunity.”
“I am not worried” because many changes to the genetic code would probably be needed to undermine a vaccine, not just one or two mutations, Bedford wrote on Twitter. But vaccines may need to be fine-tuned over time as changes accumulate, and changes should be monitored more closely, he wrote.
Murthy stressed that the new tribe does not change the public health council to wear masks, wash hands and maintain social distance.
( Jowharwith AP)