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Reports from Britain and South Africa of new coronavirus strains that appear to spread more easily are causing alarm, but virus experts say it is unclear if that is the case or if they raise any concerns for vaccines or cause more serious illness. .
Viruses evolve naturally as they move through populations, some more than others. It is one of the reasons we need a new flu vaccine every year.
New variants, or strains, of the virus that causes COVID-19 have been observed almost since it was first detected in China almost a year ago.
On Saturday, Prime Minister Boris Johnson announced new restrictions due to the new strain, and several European Union countries have banned or limited some flights from the UK to try to limit any spread.
This is what is known about the situation.
What is worrisome about the recent strain found?
Health experts in the UK and US said the strain appears to infect more easily than others, but there is no evidence yet that it is more deadly.
Patrick Vallance, the UK government’s chief scientific adviser, said the strain “is fast moving and is becoming the dominant variant”, causing more than 60% of infections in London in December.
The strain is also concerning because it has many mutations – nearly two dozen – and some are in the spikey protein that the virus uses to bind and infect cells. That increase is the goal of current vaccines.
“I’m worried about this, sure,” but it’s too early to know how important it will ultimately turn out to be, said Dr Ravi Gupta, who studies viruses at the University of Cambridge in England. He and other researchers published a report on it on a website scientists use to quickly share developments, but the article has not been formally reviewed or published in a journal.
How do these new strains occur?
Viruses often acquire small changes of a letter or two in their genetic alphabet simply through normal evolution. A slightly modified strain may become the most common in a country or region simply because that is the strain that first took hold there or because “super spreader” events helped it take hold.
A bigger concern is when a virus mutates by changing the proteins on its surface to help it escape drugs or the immune system.
“Emerging evidence” suggests that the new coronavirus may be starting to happen, wrote Trevor Bedford, a biologist and genetic expert at the Fred Hutchinson Cancer Research Center in Seattle, on Twitter. “We have now seen the emergence and spread of several variants” that suggest this, and some show resistance to antibody treatments, he noted.
What other strains have emerged?
In April, researchers in Sweden found a virus with two genetic changes that appeared to make it about twice as infectious, Gupta said. About 6,000 cases have been reported worldwide, mainly in Denmark and England, he said.
Now several variations of that strain have appeared. Some were reported in people who obtained them from mink farms in Denmark. A new South African strain has the two changes seen above, plus a few others.
The UK one has two and more changes, including eight in the spike protein, Gupta said. It is called the “investigational variant” because its significance is not yet known.
The strain was identified in southeastern England in September and has been circulating in the area since then, a World Health Organization official told the BBC on Sunday.
Will it undermine vaccines?
Probably not, former US Food and Drug Commissioner Scott Gottlieb said on CBS’s “Face the Nation” on Sunday.
“It’s unlikely,” Gupta agreed.
President-elect Joe Biden’s surgeon general candidate Vivek Murthy said 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.”
The vaccines elicit wide-ranging responses by the immune system beyond those of the spike protein, several experts noted.
The chance that the new strains will be resistant to existing vaccines is low, but not “non-existent,” said Dr. Moncef Slaoui, the chief scientific advisor to the US government’s vaccine distribution effort, on Sunday. CNN’s “State of the Union” program.
“So far, I don’t think there has been a single variant that is resistant,” he said. “I think it is highly unlikely that this particular variant in the UK has escaped the immunity of the vaccine.”
Bedford agreed.
“I’m not concerned” because it would probably take a lot of changes to the genetic code to undermine a vaccine, not just one or two mutations, Bedford wrote on Twitter. But vaccines may need to be adjusted over time as changes accumulate, and changes need to be more closely monitored, he wrote.
Murthy said the new strain does not change public health advice to wear masks, wash hands and maintain social distance.
