The public health laboratory says providing precise figures for variant cases is challenging, in part because of the delay to complete whole-genome sequencing and because not all the samples can be sequenced. (Medicago)

The public health laboratory says providing precise figures for variant cases is challenging, in part because of the delay to complete whole-genome sequencing and because not all the samples can be sequenced. (Medicago)

Variants of concern higher than reported, but giving precise data challenging: BCCDC

Director Mel Krajden attributes it to a delay to complete whole-genome sequencing and not all the samples can be sequenced

A medical director at the British Columbia Centre for Disease Control says the number of active COVID-19 cases that are variants of concern is higher than what has been publicly reported in the province.

But Mel Krajden, director of the centre’s public health laboratory, says providing precise figures for these variant cases is challenging, in part because of the delay to complete whole-genome sequencing and because not all the samples can be sequenced.

Data scientists have been calling for more timely, comprehensive information about the variants of concern in B.C. in order to help residents understand the seriousness of the threat and to persuade those who are ignoring public-health orders to follow them.

Dr. Bonnie Henry said this week that only three per cent of B.C.’s active cases are variants of concern, referring to those that have been confirmed through sequencing. Krajden acknowledged that is “not an accurate representation” of what is happening in the province.

“The numbers are high. Let’s not con ourselves. The numbers are high and they’re not going to get lower. Because this is the same trajectory that we’re following, that Alberta’s following, that Ontario’s following, so we’re not going to get out of this,” he said.

“Either that or you shut down the whole economy, and we’ve been reluctant to be so draconian.”

He said variant of concern cases are doubling about every eight to 10 days and will ultimately replace other COVID-19 strains. But he also said scientists are tracking the variants in a range of ways that go beyond just quantifying them.

“They’re looking at the trends. They’re looking at the people in hospitals. They’re looking at the severity of disease,” he said. “It’s being looked at from many, many different angles, to find: ‘What’s the right solution?’”

Experts say that B.C.’s reliance on time-consuming whole-genome sequencing is not necessary to report cases that are variants of concern. The province already quickly screens about 90 per cent of cases for a mutation that the three major variants have in common.

Ontario reports the number of presumptive variant cases every day based on this quick screening process. It then does whole-genome sequencing on some samples to distinguish between the P.1 variant first identified in Brazil and the B.1.351 variant first found in South Africa.

Health officials in B.C. have been reluctant to provide the numbers of presumptive variants of concern because some samples could end up being so-called “variants of interest” that have not been shown to be more transmissible, such as the strain first detected in Nigeria.

However, experts say that the current numbers being given only after confirmation by whole-genome sequencing are not accurate either, because B.C. does not have the capacity to sequence every case.

New data provided by the BC Centre for Disease Control gives insight, for the first time, on the number of presumptive variant cases being picked up by quick screening as part of the PCR test from January through March.

In the second week of January, there were two presumptive variant of concern cases. By the first week of February, there were 22, and by the first week of March there were 438. In the final week of March, there were 2,514, or 51 per cent of B.C.’s positive cases.

Cases confirmed through sequencing in the week of March 21 show 1,183 cases, or 21 per cent of B.C.’s positive cases. This same week, Henry told reporters that the portion of cases that were variants of concern was in the “high teens” to “early 20s.”

The centre for disease control notes that there is a weeklong delay for whole-genome sequencing. Krajden said the province has the capacity to sequence about 1,900 cases a week, though the data shows more than 2,000 cases were sequenced the week of Mar. 21.

Whole-genome sequencing for the final week of March has not yet been completed, and Krajden said the province stopped trying to sequence all variant of concern cases as of April 1.

“What we wanted to make sure is that we don’t waste our energy on confirming a U.K. variant,” he said, adding that sequencing will still be necessary to distinguish between the variants first identified in Brazil and South Africa.

“What we’re really trying to do is be as clear as possible about what’s circulating, what are the risks, are we able to detect enough variants of interest, can we do the correlations between what happens to someone who has one of these variants.”

Henry said earlier this week that the province was still sequencing all presumptive variant of concern cases. She indicated, though, that it might stop sequencing those presumed to be the B.1.1.7 variant first identified in the U.K.

The Health Ministry did not immediately respond to a request for comment.

Krajden explained that there are other challenges involved in reporting accurate numbers of variant of concern cases.

Different laboratories use different screens as part of their PCR tests, with St. Paul’s Hospital, for example, developing a screen that can distinguish between the three major variants, while others may only pick up the mutation associated with all three.

Another issue is that some samples can’t be sequenced because the amount of viral load isn’t high enough, he added.

He said he understands the public is being “driven crazy” and wants more precise data, and his centre is trying to present the information in as accurate and clear a way as possible.

But he stressed the ultimate goal was immunizing all eligible adults who want the vaccine.

“The endgame is through vaccination, converting a virus that causes severe … disease and death in predominantly the elderly into a virus that causes basically the typical common cold.”

CoronavirusHealth

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Highway 97A in Armstrong was closed in both directions Monday afternoon, just after 4 p.m., due to a serious accident at Rosedale Avenue. (Bob Dunbar photo)
No merge lanes needed on Armstrong’s Highway 97 access points: ministry

Transportation Ministry reviews accident reports, slope stability with city staff

Donna Kaufmann was named the 2021 Rotary RCMP Volunteer of the Year. (RCMP)
Vernon RCMP volunteer of the year named

Donna Kaufmann dubbed winner for positive impact on community

Lauren Marchand and her daughter at the head of Okanagan Lake in Syilx territory, where they often go to gather, play and be in ceremony. Photo by Kelsie Kilawna
‘I don’t feel safe’: RCMP, social worker searched Syilx mother’s home without her knowledge

RCMP searched the home looking for a meth lab, that was never found inside the residence

Tom Smithwick has written a new book, Knocking On Freedom’s Door, about his experiences advocating for a drug addiction treatment program in Kelowna. (File photo)
‘Knocking On Freedom’s Door’: A retired Kelowna lawyer’s insights to mental illness, addiction

Freedom’s Doors advocate Tom Smithwick shares what he has learned from experiences of treatment program clients in new book

B.C. Health Minister Adrian Dix and Premier John Horgan describe vaccine rollout at the legislature, March 29, 2021. (B.C. government)
1,262 more COVID-19 infections in B.C. Friday, 9,574 active cases

Province’s mass vaccination reaches one million people

Two-year-old Ivy McLeod, seen here on April 9, 2021 with four-year-old sister Elena and mom Vanessa, was born with limb differences. The family, including husband/dad Sean McLeod, is looking for a family puppy that also has a limb difference. (Jenna Hauck/ Chilliwack Progress)
B.C. family looking for puppy with limb difference, just like 2-year-old Ivy

Ivy McLeod born as bilateral amputee, now her family wants to find ‘companion’ puppy for her

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

This illustration provided by the Centers for Disease Control and Prevention in January 2020 shows the 2019 Novel Coronavirus.[CDC]
More COVID-19 exposures reported at schools in Kelowna

Interior Health added additional schools and dates to their list of exposures

Join Black Press Media and Do Some Good
Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

A vehicle that was driven through the wall of a parkade at Uptown Shopping Centre and into the nearby Walmart on April 9 was removed through another hole in the wall later that night. (Photo via Saanich Police Department and Ayush Kakkar)
Vehicle launched into B.C. Walmart removed following rescue of trapped workers

Crews cut new hole in parkade wall to remove vehicle safely

Four members with Divers for Cleaner Lakes and Oceans were out at Cultus Lake on March 28 and 29 hauling trash out of the waters. (Henry Wang)
PHOTOS: Out-of-town divers remove 100s of pounds of trash from Cultus Lake

Members of Divers for Cleaner Lakes and Oceans hauled out 470 pounds of trash over two days

As of Saturday, April 10, people born in 1961 are the latest to be eligible for a COVID-19 vaccine. (Black Press files)
B.C. residents age 60+ can now register to get their COVID-19 vaccine

Vaccine registration is now open to people born in 1961 or earlier

A new saline gargle test, made in B.C., will soon be replacing COVID-19 nasal swab tests for kids. (PHSA screenshot)
Take-home COVID-19 tests available for some B.C. students who fall ill at school

BC Children’s Hospital plans to provide 1,200 kits to Vancouver district schools this April

Most Read