Reports from Britain and South Africa of new strains of coronavirus appearing to spread more easily are raising alarm, but virus experts say it is unclear whether this is the case and whether they are of concern for vaccines or cause a more serious disease.
Viruses naturally evolve as they move through the population, some more than others. It’s one reason we need a new flu shot every year.
New variants, or strains, of the virus that causes COVID-19 were first discovered in China nearly a year ago.
On Saturday, Prime Minister Boris Johnson announced new restrictions due to the new species, and several countries of the European Union have banned or restricted some flights from the UK to try and limit any spread.
This is what is known about the situation.
What is so concerning about the recently found species?
Health experts in the UK and US said the species appears to be easier to infect than others, but there is no evidence yet that it is more deadly.
Patrick Vallance, the UK government’s chief scientific adviser, said the species is “moving fast and becoming the dominant variety”, causing more than 60% of infections in London in December.
The strain is also concerning because it has so many mutations – nearly two dozen – and some are on the spiny protein that the virus uses to attach to and infect cells. That peak is what current vaccines target.
“I’m certainly concerned about this,” but it’s too early to know how important it will eventually prove to be, said Dr. Ravi Gupta, who studies viruses at Cambridge University in England. He and other researchers posted a report of it on a website that scientists use to quickly share developments, but the paper has not been formally reviewed or published in a journal.
How do these new species arise?
Viruses often get small changes of a letter or two in their genetic alphabet just through normal evolution. A slightly modified strain may become the most common strain in a country or region just because that was the strain that first emerged there or because “ super spreader ” events helped anchor it.
A bigger concern is when a virus mutates by altering the proteins on its surface to help it escape drugs or the immune system.
“Emerging evidence” suggests this may be starting to happen with the novel coronavirus, Trevor Bedford, a biologist and genetics expert at Fred Hutchinson Cancer Research Center in Seattle, wrote on Twitter. “We have now seen the emergence and spread of several variants” suggesting this, and some showing resistance to antibody treatments, he noted.
What other species have emerged?
In April, researchers in Sweden found a virus with two genetic changes that made it about twice as contagious, Gupta said. About 6,000 cases have been reported worldwide, mainly in Denmark and England, he said.
Several varieties of that species have now surfaced. Some were reported in people who got them from mink farms in Denmark. A new South African species has the two changes seen before, plus some others.
The one in the UK has the two changes and more, including eight for the spike protein, Gupta said. It is called a “variant under investigation” because its meaning is not yet known.
The species was identified in southeast England in September and has been circulating in the area ever since, 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” Sunday.
“Unlikely,” Gupta agreed.
Vivek Murthy, surgeon candidate for President-elect Joe Biden, said on NBC’s “Meet the Press” Sunday that there is “no reason to believe that the vaccines that have been developed will also be ineffective against this virus.”
Vaccines produce wide-ranging immune system responses beyond just those to the spike 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 US government’s chief science adviser for vaccine distribution, in CNN’s “State of the Union” Sunday.
“So far I don’t think there is a single variety that would be resistant,” he said. “This particular variant in the UK, I think, has most likely not escaped vaccine immunity.”
Bedford agreed.
“I’m not worried” because it likely takes many changes in 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 monitored more closely, he wrote.
Murthy said the new strain does not change public health advice to wear masks, wash hands, and maintain social distance.