How accurate is Canada’s data?
ATTEMPTS TO ‘FLATTEN THE
CURVE’ HAMPERED BY INFORMATION LAG, SHIFTS IN TEST POLICIES
Canada’s political and public health leaders are all in agreement: we’re entering a critical phase of the COVID-19 pandemic as we discover whether the lockdowns implemented two weeks ago are working and we’re starting to flatten the curve.
But as we watch to see whether the case numbers slow down in growth, experts say it is also important to remember just how imperfect the data is.
“The numbers, in terms of the reported cases across the country, regardless of what country in the world one is talking about, will always represent an underestimate of what’s really out there,” said Peter Phillips, a clinical professor specializing in infectious diseases at the University of British Columbia.
For starters, case numbers are always at least two weeks behind the true situation due to the lag time in infected people developing symptoms and then getting test results.
But Phillips is particularly concerned about Canada claiming it’s flattening the curve, while testing criteria remains limited in many jurisdictions, often because of lingering concerns around lab capacity and supplies.
“It’s all a function of testing, right?” he said. “Your numbers might get lower and lower. But if it’s because you’re putting in more restrictive testing policies, that’s not surprising. It might not be good news, it might just be a function of the fact that you’re not testing as much as you used to be.”
Different provinces have different policies, which means comparisons across Canada always come with large caveats.
British Columbia is one to watch because it was where COVID-19 first took off in Canada (at least identifiably), and is also now the first province expressing cautious optimism that physical-distancing measures are working.
“I’m trying not to over-call it, but I do believe we’ve seen a flattening, a falling-off of that curve,” said B.C.’s provincial health officer Bonnie Henry on March 27.
However, B.C. also tightened its testing criteria earlier in March, in part because of a backlog at its labs. It now focuses its testing on health-care workers, residents of long-term care facilities, people requiring hospitalization, and people possibly connected to a “cluster or outbreak.”
On March 28, Henry said it may still be a while until the province is testing more broadly in the community.
“At this point in our epidemic, the important thing is identifying those chains of transmission and where people are getting sick,” Henry said.
Some critical care doctors and public health authorities in the three most virus-ridden provinces say they believe there are enough ICU beds and respirators, especially if the epidemic curve is kept flatter than some of the world’s hardest-hit jurisdictions. All are urging the public to help by keeping up social distancing.
One definite concern is the availability of masks and visors, among the most important pieces of personal protective equipment for health workers.
Staff in some hospitals are already being limited to using just two disposable masks a day, and Buchman.
“I have access to narcotics more easily than N95 masks,” says Dr. Yoanna Skrobik, a critical-care medicine professor at the University of Montreal.
When she last checked, her hospital had no Plexiglas visors, used for working close up to infected patients who might who might expel aerosolized particles.
Dr. Alan Drummond said the Perth, Ont., hospital where he works part-time in the emergency department has a two-mask limit per shift, even though Ontario Health Minister Christine Elliott insisted recently the gear was not, in fact, being rationed.
“I wouldn’t say they have lied to us, but they haven’t been truthful,” said Drummond, a spokesman for the Canadian Association of Emergency Physicians. “Government response has been desultory, incremental, reactive. We’ve been getting cross messaging right from the get go, and government has been slow to respond.”
He acknowledges that for now there is something of a lull, at least in emergency. Many of the departments across Canada are actually unusually quiet, he said.
Two factors seem to have temporarily lessened pressure on hospitals: social distancing that some data suggest has curbed the number of new infections, and the cancellation of elective surgeries and other measures that reduced the patient population in hospitals.
But, said Drummond, “there is a very definite, palpable sense of calm before the storm.”
If Canada, or parts of it, do experience a surge of very ill COVID-19 patients like southern Europe or New York, evidence from those places indicates the crunch will come in intensive care units, where the sickest two to three per cent of patients end up.
As a whole, this country has more ICU beds per 100,000 people — about 14 — than some Western European countries, including hard-hit Italy and Spain and the UK, but less than Belgium, Germany — 25 — and the U.S. — 20, according to the Canadian Institute for Health Information.
Meanwhile, FoxRobichaud says ordinary Canadians can play a role by thinking about whether they would actually want to receive intensive treatment, like being put on a ventilator with a tube stuck down their throat.
“This virus is knocking down not just the elderly, but young people, and everybody has to have an understanding … would they want all the things we do in critical care?” she said.