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.
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.”
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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