New lineages of the virus responsible for COVID-19 have led to travel bans and concerns over increased transmissibility, but experts say it's unclear whether the latest strains are more potent than previous versions.
One strain has appeared to dominate infections in the U.K. over the last month while another new lineage has been spreading in South Africa. Both countries are experiencing high rates of transmission recently, and an epidemiologist in the U.K. suggested mutations on the new strand could be making the virus 70 per cent more infectious.
Health Canada said on Sunday there's nothing suggesting at this point that the new mutations have any effect on symptom severity, antibody response or vaccine efficacy.
Dr. Gerald Evans, an infectious disease expert with Queen's University in Kingston, Ont., agrees, saying we need more evidence before determining potential impacts.
“If it pans out that yes, it is more transmissible, then that's relevant and gosh, we're going to have to address this,” Evans said.
“What we're getting is a lot of people scared because they're hearing about mutant viruses... I'm just frustrated because I need to see (evidence).”
Evans said it would make sense to see a new strain appearing more frequently in areas where rates of community transmission are already “exploding.”
But that could be more due to peoples' behaviour than a change in the virus itself, he said.
Jason Kindrachuk, a virologist with the University of Manitoba, says the rate at which we're seeing the new strain in the U.K. seems to suggest there's more going on than just relaxed restrictions and behavioural patterns, though.
And while he agrees more research is needed before we can glean the significance of the mutations, that's going to take time.
“We're in this difficult period where something interesting has shown up, but now we have to try and biologically validate what that means,” he said. “And that's not necessarily easy to do in real time as a virus is spreading.
“But we need to actually do these experiments and see: can we demonstrate there's an advantage in those new strains compared to other variants we've seen for SARS-CoV-2? And there will be massive mental focus on this in laboratories across the world over the next few weeks.”
Genomic sequencing of the virus has shown the U.K. strand has already spread to other countries, but Health Canada said Sunday there have been no recorded cases of the new strain here.
The Canadian government began restricting travel from the U.K. for 72 hours beginning Monday in an effort to keep the new strain of the virus out of the country. Several European countries recently announced they too were closing their borders to the U.K.
Dr. David Williams, Ontario's chief medical officer, said it's important to make sure the new strain doesn't start to spread in this country, for instance by a traveller not respecting quarantine.
He also said the province's genomic sequencing of the virus is happening at “light speed.”
“We're keeping an eye on it, we're watching for it, and we're watching to make sure what's happening to the strains that are circulating here,” he said. “So it's that ongoing vigilance and laboratory surveillance that's critical as well, and it certainly would inform the citizens of Ontario if there was a risk.”
A report on the preliminary genomic characterization of the U.K. strain says a “distinct cluster” of the virus has “an unusually large number of genetic changes, particularly in the spike protein.”
That protein is what the newly developed vaccines are targeting, but Art Poon, a virus evolution researcher at Western University, doesn't expect the mutations to impact vaccine effectiveness.
“Many of these (mutations) are pretty familiar to us and we would have anticipated that in the development of the vaccine,” he said. “But we also shouldn't be giving the virus so many chances to change.”
There have been several mutations to SARS-CoV-2 since it first began circulating late last year, and Poon says part of the reason for that was our inability to stifle the virus in the first place.
“When you have more of the virus circulating, there's more chance for the virus to mutate,” he said.
“But in terms of what we can do about it: all the standard recommendations to reduce transmission - reduce your number of contacts, stay at home if you can, wear a mask -those things will help prevent these lineages from arising.”
This report by The Canadian Press was first published Dec. 21, 2020.
