The coronavirus variant that forced the Whistler Blackcomb ski resort to close is spreading rapidly in B.C. and sending more young people to hospital, raising concern about health officials’ ability to control the outbreak that is the largest known spread outside Brazil.
Whistler recorded 1,120 COVID-19 cases from the beginning of January to March 28, with 218 of them last week alone, driven by the P.1 variant most commonly associated with Brazil. The majority of cases – 83.2 per cent – are in people aged 20 to 39.
The rapid growth of cases highlights the need for more testing to identify emerging threats as much of the country deals with a third wave, said microbiologist Marc Romney, a clinical associate professor at the University of British Columbia.
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.
Need more answers? Email email@example.com
Whistler-specific data for P.1 variant cases were unavailable on Thursday. However, a laboratory at St. Paul’s Hospital that screens positive samples from most of the Vancouver Coastal region – which includes Whistler – for variants using a new rapid-testing technology, had confirmed 480 cases of the P.1 variant by Wednesday night – already more than what has been reported by any other country except for Brazil.
The province, whose figures lag behind, reported 379 cases of the variant on Thursday, most in the Vancouver Coastal region.
Researchers detected a cluster of 13 P.1 cases in the region on March 9. It was unexpected, as the variant had not yet been reported in Canada outside Ontario.
On Thursday, Provincial Health Officer Bonnie Henry said officials were most concerned about the P.1 variant, which has spread through the resort municipality “to other parts of the province in very small numbers,” and has led to more young people requiring hospitalization.
“Younger people are, thankfully, more likely to survive,” she said. “We know length of [hospital] stay is longer and they more often are needing ICU care.”
Whistler Blackcomb was ordered closed on Tuesday, as British Columbia implemented a three-week circuit breaker in a bid to slow the troubling increase in COVID-19 cases driven by the more transmissible coronavirus variants. The ski resort has since announced it will stay closed for the rest of the season.
While the B.1.1.7 variant first identified in Britain still makes up the largest proportion of variant cases in B.C., officials are keeping a close eye on P.1.
Emerging research has shown the P.1 variant to be up to 2.5 times more transmissible than the common SARS-CoV-2 strain. A separate study found that out of 100 people to contract COVID-19, 25 to 60 could become infected again with the variant.
The initial P.1 cluster in B.C. was detected with the new rapid-testing strategy, which scans the genomic sequence of the virus for a mutation common to all current variants of concern but lacking in the standard SARS-CoV-2. Samples with this mutation are further analyzed to determine the specific variant.
The current practice of sequencing the whole genome can take several days, and sometimes up to a week, while the new method produces results the same day.
Dr. Romney, who developed the testing strategy with his team at St. Paul’s, wants the province to implement it widely as a complement to whole-genome sequencing, emphasizing that the early and rapid detection of variants of concern is of utmost importance.
“It’s flexible, modular and versatile, so if more variants of concern appear over time, we can easily modify our testing strategy to include mutations associated with those,” Dr. Romney said. “Most importantly, it’s rapid. Every positive that we identify in the lab goes for variant testing on the same day. It’s real-time surveillance.”
Public health officials had allowed skiing over the winter, but advised people to stick to local mountains and avoid après-ski gatherings. However, clusters of cases in Whistler and Big White Ski Resort in the Interior were traced to dorm-style staff housing and social gatherings.
Big White fired some staff members after 60 cases in late December, and terminated the lease of a restaurant this week after video surfaced of a crowded indoor gathering on Monday with people drinking and dancing on tables.
Dr. Henry said an immunization program at the staff accommodations in Whistler, and increased efforts to isolate workers, were not enough, and cases were climbing because of the P.1 variant. Contact tracers have also confirmed transmission related to travel between Whistler and other communities across B.C., she said.
WorkSafeBC completed 62 inspections and 38 consultations between Jan. 30 and 31, issuing a total of 34 orders. There have also been a slew of exposure notices in recent months for bars and restaurants in Whistler.
Albert de Villiers, chief medical health officer for Interior Health, said on Thursday that the region had to date confirmed 70 cases of variants, 27 of which are P.1. The Interior had four active confirmed P.1 cases, and they are believed to be contained. However, screening for variants of concern can take up to a week, he said.
Health columnist André Picard answers reader questions about COVID-19 variants, how effective the various vaccines are and the impact of on-again, off-again lockdowns.
The Globe and Mail
Sign up for the Coronavirus Update newsletter to read the day’s essential coronavirus news, features and explainers written by Globe reporters and editors.