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.
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.
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