Modelling experts urge B.C. to urgently speed up vaccinations as threat of mutations grows
Province will not reach herd immunity by fall at current vaccination rates, mathematical modellers say
Health officials in B.C. are being urged to accelerate the province's vaccine rollout over fears a constantly mutating virus could outrun currently available vaccines if left to spread without control for months.
Modelling experts at Simon Fraser University say the threat of a variant mutation that will render vaccines useless is a looming fear and opportunities to stem the spread of current variants in B.C. were lost.
Their call comes as B.C. moves to put stricter travel restrictions in place, and as the federal government is set to ban passenger flights from India and Pakistan for 30 days.
But two COVID modellers say they wish B.C. had been less sluggish with such measures, before COVID-19 variants of concern got a foothold. Now, the number of variant cases are so high that B.C. is no longer sequencing every case and is, instead, assuming most are a variant of concern.
"I don't think [measures] are too late but it would have been great to have them earlier," said Paul Tupper, a professor of mathematics at Simon Fraser University.
"The only way out of this mess that we are in is through vaccination — so the more of the population we are able to vaccinate safely, the better."
Tupper and his colleague Caroline Colijn say targeted and fast inoculations will make the best dent in the rising number of cases. But longer-term, the evolution of variants is "worrying" — and both believe it's only a matter of time before a mutation spawns that escapes the reach of current vaccines.
Vaccinations must be ramped up to reach herd immunity
Colijn and Tupper say simulations show that at the current rate of vaccinations, B.C. will not achieve herd immunity by this fall, as hoped.
At best, they say, B.C. will be able to protect about 51 per cent of the population, even if they are able to jab every eligible adult with a vaccine by September. That would leave the province short about nine percentage points, as it's estimated 60 per cent of the population would have to be protected to achieve herd immunity.
For Colijn, that makes more inoculations an urgent need. She said each death is a failure to protect people.
"We've gone for this mitigation approach and this is the consequence of it — and it's a known consequence," she said.
"A two-year-old. A nurse. Whether they have diabetes or other complications or not — it's still tragic that we let people be exposed."
On Thursday, Provincial Health Officer Dr. Bonnie Henry said although modelling is helpful, it doesn't always reflect real world experience.
"What I took away from that model is that one of the most important things we need to address is getting high rates of immunization across all age groups," she said.
"I know they used 80 per cent as one their parameters. Models are very dependent on what you put in them. We have very high rates, higher than 80 per cent in some age groups."
CBC's vaccine tracker shows that, as of Wednesday, B.C. had distributed 1,731,470 doses of vaccine — around 84 per cent of the doses the federal government has sent the province. To ramp up inoculations, B.C. would require more doses than currently available, though more vaccine is expected in the coming weeks.
There are currently 163 active cases related to three variants now circulating in B.C., according to the BCCDC.
On Wednesday, the province confirmed B.C. has recorded 39 cases of the B1617 strain now driving a record surge in India. The variant has two mutations and is associated with a poorer antibody response, according to an immunologist with the Institut national de la recherche scientifique in Quebec.
A variant becomes a variant of concern when its changes have a clinical or public health significance: for example, if it affects the transmission, severity, vaccine effectiveness and/or diagnostic testing of the disease.
B.C.'s Provincial Health Officer Dr. Bonnie Henry said on Thursday some B1617 cases are associated with direct travel from India, but others are not travel linked.
"It's a tragedy globally that we are seeing, and India is bearing the brunt of it right now," Henry said.
"We are very supportive of the federal government stopping flights coming into Canada right now."
Variants are also of greater concern to younger people, who are also last in line for the vaccine in accordance with B.C.'s age-based vaccination distribution.
Dr. Hussein Kanji, a medical director at Vancouver General Hospital, said hospitals in the province are under unprecedented pressure, with doctors assuming most cases are associated with the variants. He said patients under the age of 20 in B.C. have been intubated.
"There are patients that are in their 20s, 30s, 50s in much, much larger concentrations than we had the first time around," he said, adding doctors and nurses do not know which of the patients they are treating have variant cases.
"That adds a level of angst."
Early warnings ignored
Colijn said Canadian health officials were warned early in 2021 about the potential of a variant with a higher transmission rate — and that the variant first detected in the U.K. gave a clear and rare picture of how a more transmissible variant can quickly threaten the stability of health-care systems.
But Colijn said despite warnings from modellers, provinces failed to act — a failure she hopes won't be repeated.
"It was disregarded because total case numbers were low, so how could there be something growing?" she said. "Public health and policymakers did not get the message that high-transmission is a serious, serious thing."