Scientists racing to understand new COVID-19 variants and whether they will derail vaccination efforts
Researchers warn future sets of mutations could evade current SARS-CoV-2 vaccines
After the virus behind COVID-19 spent 2020 wreaking havoc around the globe, this year started with a bit more hope — vaccination efforts were ramping up, after all — and a tinge of fear.
Multiple new coronavirus variants have been discovered across several continents, from Europe to Africa to South America. Confirmed cases keep popping up in dozens of countries, Canada included.
Scientists are now racing to understand these sets of mutations, all while concerns are growing over their ability to infect people more easily or, in some cases, potentially evade the army of antibodies we create after being infected or vaccinated.
And since widespread transmission means this virus has ample opportunities to mutate again and again and again, these variants won't be the last. They're just the ones we know about.
"The more opportunity we give to the virus to replicate, to make more viruses, the more opportunity there is to see that variant of concern — one that won't be mitigated by our vaccines that we've developed," warned Alyson Kelvin, a virologist at Dalhousie University and the IWK Health Centre in Halifax.
After months of work to develop safe, effective vaccines against SARS-CoV-2, the scientific community now faces a race against time to ward off that scenario.
There's also a looming question: What happens if we don't?
Variants could 'very rapidly' become prevalent
Kelvin, one of the many Canadian researchers involved in vaccine development, said preliminary data shows that the sets of mutations identified so far don't yet seem to be an issue for current coronavirus vaccines.
That's the good news. It's the "yet" she finds troubling.
"We have to stay on top of this problem," Kelvin said.
But while new variants might throw a wrench in efforts to suppress transmission by popping up like a game of global whack-a-mole, those ongoing mutations were actually expected, not surprising.
That's because each virus has a singular goal of replicating itself. With tens of millions of people helping move the coronavirus back and forth between hosts, that means countless replications. Some of those contain random, insignificant mistakes. And when the mistakes prove beneficial to the virus, helping it produce more copies, those errors can become a new normal of sorts — a variant.
It's just evolution at work, said Angela Rasmussen, a virologist at Georgetown University's Center for Global Health Science and Security in Washington, D.C., and incoming research scientist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan in Saskatoon.
"What concerns me the most is that the epidemiological data that goes along with some of these variants suggests they could very rapidly become very prevalent — effectively out-competing the other variants in a given area — in a short period of time," she said.
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Could new variants decrease immune response?
Researchers speculate that may be what happened with B117. The variant was first discovered in the U.K. late last year and is now the country's dominant strain of the coronavirus — with various officials suggesting it's at least 50 per cent more transmissible. (Cases have been confirmed in several provinces in Canada as well, and testing is ongoing.)
In the short term, more transmission means more infections, hospitalizations and deaths, Rasmussen said, which offers an incentive for countries to slow case growth. Doing so would both save lives and cut off channels for the virus to spread and mutate.
"It's also possible that variants may arise that decrease the effectiveness of our immune response to the virus," said Matthew Miller, a member of the Institute for Infectious Disease Research at McMaster University and the McMaster Immunology Research Centre in Hamilton.
"But also, of course — and perhaps more worryingly — the immune responses elicited by the currently approved vaccines."
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For scientists in Brazil, there's already legitimate cause for alarm.
"We have detected a new variant circulating in December in Manaus, Amazonas state, north Brazil, where very high attack rates have been estimated previously," read the preliminary findings posted online by a research team led by Imperial College London virologist Nuno Faria.
The new lineage, dubbed P1, contains a "unique constellation" of mutations in the crucial spike protein, which helps the virus penetrate human cells, the report continues. The variant was detected in 42 per cent of samples collected during a stretch in December, but not in samples collected in the months before.
Those new cases also appeared even though an estimated three-quarters of people living in Manaus, the largest city in the Amazon region, had already been infected.
Faria's report stressed that could mean an increase in transmissibility — the same issue with B117 — or even an ability to reinfect people.
Vaccines 'modifiable' in face of new mutations
According to Rasmussen, antibodies seem to have a reduced capacity to neutralize this kind of virus variant based on the spike protein mutations. Echoing Kelvin and Miller's concerns, she said that's a key problem, "because if you acquire enough of those mutations, you may get to a point where you have a variant capable of evading vaccine-induced immunity completely."
But again, it's not all dire news. Just because antibodies are less effective doesn't necessarily mean someone would have reduced immune protection, Rasmussen explained, since the body's immune response is looking at the entire spike protein, not just certain areas that might have a set of mutations.
Miller also noted that while the spike protein tends to be most prone to changing in the face of immunological pressure, there are other vaccine candidates in development that are designed to elicit broader immune responses against a greater array of viral targets to stay one step ahead.
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"Even in the worst-case scenario, that we see some of these variants spreading and we get a partial response, it's probably going to mean that the health-care complications, the deaths, are still going to be greatly controlled by a mass vaccine campaign," said Dr. Zain Chagla, an infectious disease specialist at McMaster University.
And, thankfully, research teams can also pivot, redeveloping existing coronavirus vaccines to target any variants that may prove capable of evading the ones already rolling out globally.
The novel mRNA vaccines, including the Pfizer-BioNTech and Moderna options currently approved in Canada, are among those that can be more easily tweaked. Those vaccines provide instructions — messenger RNA — to cells, allowing them to make their own spike protein, which someone's immune system can recognize and fight off in the future.
"That is their genius, that they're completely and rapidly modifiable," Chagla said. "The packaging is there, the delivery method is there, all you need to do is change the mRNA sequence."
The sooner people get vaccinated, 'the better'
But while the flexibility of vaccination development is reassuring for the long term, it doesn't tackle the problem at hand: COVID-19 still has its grip on much of the world, the death toll keeps climbing and vaccination efforts remain a race against time as emerging variants keep throwing a wrench in efforts to curb transmission.
"The sooner that we can get a vaccine into people, the better," Kelvin said.
To save lives and keep health-care systems from collapsing while vaccination programs scale up, she stressed that Canadians also need to ramp up the basic public health precautions that should now be routine.
Physical distancing, mask-wearing, hand-washing, staying away from crowds and enclosed spaces — it all matters, perhaps now more than ever, to slow transmission and give the virus fewer opportunities to spread and evolve.
That buys time for Canada to hit its tenuous goal for 2021: getting everyone vaccinated, without any variants getting in the way.
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