Question: Why are the new variants of the coronavirus so contagious and how can I protect myself from them?
Answer: The first thing you need to know is that the emergence of new variants is a normal and expected development.
It’s a process that happens when the virus commandeers the molecular machinery of an infected human cell to replicate itself. Tiny copying errors, or mutations, occasionally occur as 30,000 letters of RNA are assembled to reproduce the genetic code of the virus.
Many of these random changes have no discernable effect and may even be detrimental to the virus. But a few of them will provide some type of competitive advantage.
“This is evolution at work,” explains Dr. Peter Juni, scientific director of Ontario’s COVID-19 Scientific Advisory Table. The mutations that increase the chances of a new variant spreading tend to keep getting passed along.
COVID-19 is caused by a virus called SARS-CoV-2, and as it spread around the world, it mutated into new forms that are more quickly and easily transmitted through small water droplets in the air. Canadian health officials are most worried about variants that can slip past human immune systems because of a different shape in the spiky protein that latches onto our cells. The bigger fear is that future mutations could be vaccine-resistant, which would make it necessary to tweak existing drugs or develop a new “multivalent” vaccine that works against many types, which could take months or years.
Not all variants are considered equal threats: Only those proven to be more contagious or resistant to physical-distancing measures are considered by the World Health Organization to be “variants of concern.” Five of these been found in Canada so far. The WHO refers to them by a sequence of letters and numbers known as Pango nomenclature, but in May of 2021, it also assigned them Greek letters that experts felt would be easier to remember.
- Country of origin: Britain
- Traits: Pfizer-BioNTech and Moderna vaccines are still mostly effective against it, studies suggest, but for full protection, the booster is essential: With only a first dose, the effectiveness is only about 66 per cent.
- Spread in Canada: First detected in Ontario’s Durham Region in December. It is now Canada’s most common variant type. Every province has had at least one case; Ontario, Quebec and the western provinces have had thousands.
- Country of origin: South Africa
- Traits: Some vaccines (including Pfizer’s and Oxford-AstraZeneca’s) appear to be less effective but researchers are still trying to learn more and make sure future versions of their drugs can be modified to fight it.
- Spread in Canada: First case recorded in Mississauga in February. All but a few provinces have had at least one case, but nowhere near as many as B.1.1.7.
- Country of origin: Brazil
- Traits: Potentially able to reinfect people who’ve recovered from COVID-19.
- Spread in Canada: B.C. has had hundreds of cases, the largest known concentration of P.1 outside Brazil. More outbreaks have been detected in Ontario and the Prairies.
DELTA (B.1.617 AND B.1.617.2)
- Country of origin: India
- Traits: Spreads more easily. Single-dosed people are less protected against it than those with both vaccine doses.
- Spread in Canada: All but a few provinces have recorded cases, but B.C.’s total has been the largest so far.
- Country of origin: Peru
- Traits: Spreads more easily. Health officials had been monitoring it since last August, but the WHO only designated it a variant of concern in June of 2021.
- Spread in Canada: A handful of travel-related cases were first detected in early July.
If I’m sick, how do I know whether I have a variant?
Health officials need to genetically sequence test samples to see whether it’s the regular virus or a variant, and not everyone’s sample will get screened. It’s safe to assume that, whatever the official variant tallies are in your province, the real numbers are higher. But for your purposes, it doesn’t matter whether you contract a variant or not: Act as though you’re highly contagious, and that you have been since before your symptoms appeared (remember, COVID-19 can be spread asymptomatically). Self-isolate for two weeks. If you have the COVID Alert app, use it to report your test result so others who may have been exposed to you will know to take precautions.
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Scientists are still trying to determine how the latest variants differ from the original version of SARS-CoV-2, the official name of the novel coronavirus that causes COVID-19.
Dr. Juni says the worrisome variants that were first detected in the U.K., South Africa and Brazil all have mutations in the genes that produce spike proteins, the knobby protrusions that the virus uses to latch onto receptors on the surfaces of certain human cells.
He thinks these mutations enable the spike proteins “to fit more snugly” and create a “tighter fit” on the receptor, making the virus more likely to enter a human cell. This could mean “a low dose of the virus might be enough to infect the body.”
Each one of the variants may contain additional beneficial mutations that boost their odds of survival and propagation. The South African variant appears to be have some ability to evade the immune system’s antibodies, which makes certain vaccines less effective against it.
Overall, the new variants are roughly 40 per cent more transmissible than the original SARS-CoV-2.
“More mutations are coming – that’s natural. But this is not a reason to panic,” says Dr. Juni.
Pointing to the recently developed messenger-RNA vaccines, he notes that “we have new technology that will make it much easier to alter, or tweak, vaccines as new variants emerge.”
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Even more importantly, people can protect themselves from infection by adhering to well-established precautionary measures such as wearing masks, frequent hand washing and physical distancing – keeping at least two metres apart.
“I know it sounds like a broken record, but we just need to follow the same guidelines that we have been doing,” says Dr. Rob Kozak, a scientist and clinical microbiologist at Sunnybrook Health Sciences Centre in Toronto.
“The virus can’t hibernate or hide somewhere. It only exists if it keeps being transmitted to new hosts,” he adds. “So, we can stop it if we don’t become complacent and let down our guard.”
In the case of masks, they don’t necessarily need to be medical-grade. A three-layered fabric mask – which might include a disposable or washable filter – can block the transmission of the virus.
However, to be truly effective, a mask must be worn correctly – covering the nose and mouth with no gaps around the edges.
Dr. Anthony Fauci, the leading infectious-diseases physician in the United States, has publicly speculated that two masks might be better than one.
But many Canadian experts are still reluctant to embrace double-masking.
Dr. Janine McCready, an infectious-diseases physician at Michael Garron Hospital in Toronto, says some people might find that wearing two masks is hot and uncomfortable. “You may be touching your face more often to adjust the masks,” she adds.
If people really can’t find a good mask that fits, then they might consider doubling up, says Dr. McCready. But she suggests they should first explore some creative solutions. That could mean knotting the ear loops to make them shorter or using a clip to pull the loops together at the back of the head in order to tighten the seal around the face.
Although experts generally agree that basic safety procedures can block transmission of the virus, certain public-health measures may need to be revised to deal with the new and highly contagious variants.
Dr. McCready points out that some public-health units have been using 15 minutes of exposure as a key measurement in their contact-tracing efforts.
“If you need less exposure to actually get sick from the virus, then maybe we should change the 15-minute threshold,” she says. “It is probably better to test and isolate more people to make sure we are controlling the spread.”
To prevent the health care system from being overwhelmed with COVID-19 patients, additional government interventions may be necessary to limit the number of new cases, says Dr. Andrew Morris, an infectious-diseases specialist at Sinai Health and the University Health Network in Toronto.
“Providing paid sick leave is one way to reduce the rate of transmission,” says Dr. Morris. Simply put, infected essential workers can then afford to stay home so they don’t pass the illness on to others.
“These variants are concerning,” says Dr. Morris. “But we now know enough to be able to control them quite well. We just have to be smart about what we do.”
Paul Taylor is a former Patient Navigation Adviser at Sunnybrook Health Sciences Centre and Health Editor of The Globe and Mail. Find him on Twitter @epaultaylor and online at Sunnybrook’s Your Health Matters.
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