What are the different COVID-19 variants and why do they matter?
TORONTO -- More than a year after the first cases of COVID-19 were detected in Canada, several new variants of the SARS-CoV-2 virus have developed that are causing concern within the scientific and medical community.
A variant is identified when enough mutations have occurred to change a minor portion of a virus’s genetic code. There have been other variants prior to the recent ones, but they were generally no more concerning than the existing virus.
The World Health Organization and the U.S. Centers for Disease Control and Prevention (CDC), among others, are tracking these variants closely, however, due to the worrisome nature of some of the mutations.
Some changes are concerning due to the ease with which the variants attach themselves to human cells, making them much more transmissible, while others, like the Brazil variant, have also raised doubt over the effectiveness of herd immunity.
Some health experts say these variants demonstrate the urgent need to get the pandemic under control to prevent a worsening situation, with the vaccine playing a crucial role.
“Viruses cannot mutate if they don’t replicate. And if you stop their replication by vaccinating widely and not giving the virus an open playing field to continue to respond to the pressures that you put on it, you will not get mutations,” Dr. Anthony Fauci said Monday at a White House news briefing.
Here is a summary of some of the recent and earlier key variants that have attracted attention.
To further explore the evolution of SARS-CoV-2, Nextstrain.org tracks and graphs the virus’s genomic epidemiology in real-time using scientific data submitted to GISAID, a global data-sharing platform for scientists.
B.1.1.7 OR 20I/501Y.V1 VARIANT (U.K.)
This variant, which first emerged sometime in September 2020, was the first variant to draw wider public attention, after U.K.researchers found that it was up to 70 per cent more transmissible due to 22 coding changes in the virus genome.
By late December, officials said more than 60 per cent of new cases in London were of this variant.
The changes to the virus appear to make it bind more easily to human cells, which is what makes it more “efficient” and transmit more rapidly, scientists say.
U.K. researchers also reported that new analyses were indicating an increase in disease severity in those infected with this particular variant, making it a “realistic possibility that infection with (Variant of Concern) B.1.1.7 is associated with an increased risk of death.”
This variant has already spread to numerous countries around the world, including Canada. A number of cases at Roberta Place, the Barrie, Ont. long-term care facility shattered by a brutal outbreak, have been identified as the highly infectious U.K. variant. So far, 63 people have died at the home, where all but one of the residents have tested positive in addition to 104 staff members.
The variant has also been reported in B.C.
B.1.351 OR 20H/501Y.V2 VARIANT (SOUTH AFRICA)
South African authorities reported this variant in mid-December after health authorities discovered it was spreading rapidly in three provinces, quickly taking over as the main variant.
Initial studies indicate this variant has a higher viral load, making it potentially more infectious than earlier variants.
One concern some scientists have with this variant is that it is more efficient at targeting healthy cells. There is no solid evidence as yet, however, that it causes more severe illness.
P.1 LINEAGE OR 20J/501Y.V3 VARIANT (BRAZIL)
What is alarming scientists about this variant, first identified in early December in Manaus, Brazil, is that it has triggered an outbreak even more deadly than the city’s first devastating one last spring, and is spreading at a far faster pace than the worrisome U.K. variant.
Last spring’s uncontrolled outbreak in the city of 2.2 million eventually infected some 76 per cent of the population, leading many experts to believe the population was getting close to or even above the threshold for herd immunity, according to an article in The Lancet.
A recent study, however, found that this variant was found in 42 per cent of the samples sequenced from late December.
Evidence suggests the mutations in this variant could affect the ability for antibodies from either a previous infection or from vaccination to recognize the virus, according to the U.S. CDC.
Another possibility suggested in The Lancet is that immunity against infection may have begun waning by the time this variant emerged.
This variant was first detected in the United States in Minnesota in late January, but has yet to be identified in Canada.
‘CLUSTER 5’ VARIANT (DENMARK)
There are several mutated mink strains that have infected at least several hundred people in Denmark according to the European Centre for Disease Prevention and Control, and mink infections have been reported in several European countries, the United States and Canada.
But some Danish scientists had expressed concern over the ‘Cluster 5’ variant that was identified in minks in Denmark last fall, worries that eventually lead to the mass culling of the country’s entire population of up to 17 million minks.
Early studies in Denmark found this variant could potentially decrease the duration of an individual’s immune protection after infection or vaccination, making future vaccines less effective against it.
Only a dozen human cases of this variant were identified in the country, according to the WHO, with Denmark reporting this particular mutation was “most likely” eradicated.
This variant emerged in late January to early February of 2020, first in Australia and Europe as a mutation of the original SARS-CoV-2 strain that was identified in China.
According to Nextstrain and the WHO, this strain became the main form of the virus circulating around the world by June 2020, with studies indicating that it was more infectious and more easily transmissible than the original, even though it did not make individuals more sick.