There are three limbs to the epidemiologic triangle — not one.
It is unwise to be too sure of one’s own wisdom. It is healthy to be reminded that the strongest might weaken, and the wisest might err.
Pride goes before destruction, a haughty spirit before a fall.
David Staples could scarcely contain himself last Friday.
“Albertans have triumphantly answered one huge question about our response to COVID-19 with a grand slam home run,” the Edmonton Journal columnist proclaimed. “We have proven that we’re wise, diligent and responsible enough to drive down infection rates.”
“Albertans haven’t just flattened the curve,” he enthused. “We have steamrolled it and chucked it down a big hill.”
Fair enough, I suppose. The impact of the lethal coronavirus has been far less than feared in my province. Unlike the traumatized citizens of New York City, Montreal, London, and elsewhere, we haven’t been forced to climb the front side of a steep, arduous bell curve of infections.
By all means, take a bow, my fellow Albertans. We’ve played our hand well.
But it must be said that the hand we were dealt was a very good hand indeed.
The virus that is hunting for victims in my city of Calgary is the same virus that is ravaging Montreal and New York City.
Yet the death rate per capita in Montreal is more than ten times higher than it is in Calgary; in New York, more than thirty times higher.
We deserve some credit for that outcome. We worked furiously in Alberta to prepare for a massive surge of COVID patients — a surge that never materialized at least in part because of that effort.
We led the country in testing; we aggressively chased down contacts of the COVID-affected; we throttled non-essential business activity to slow spread of the virus; and our citizens, for the most part, bought into the social distancing recommendations provided by Chief Medical Officer of Health Dr. Deena Hinshaw.
Thus far, in Alberta the pandemic has delivered more menace than massacre. But we don’t deserve as much credit for that outcome as we think.
There are three limbs to the epidemiologic triangle — three key elements that contribute to the spread of disease: an external agent; a susceptible host; and an environment that brings the agent and host together.
The “external agent” in our current situation, of course, is the novel coronavirus: n-Cov-19. But the other two legs of the pandemic beast are just as critical to its mobility.
With respect to “host” and “environment”, Calgary, for example, is different from cities like New York City and Montreal, in ways that made it very unlikely for COVID-19 to cause the same carnage here as it did there.
The risk factors for becoming seriously unwell with COVID-19 are now generally accepted: if you are black, elderly, male, obese, and have medical issues like diabetes, high blood pressure, or heart problems, then you don’t want to tangle with this virus.
By the metrics of age and obesity Calgarians aren’t all that different from New Yorkers. In both cities, the median age is about 37; in both places, more than half of us are overweight — more than 20% are frankly obese (denizens of New York City are slimmer, on average, than their countrymen).
But only three percent of Calgarians are black, whereas in New York that number is twenty-five percent; in Montreal, it’s ten percent.
Blacks die from COVID-19 in America at 2.4 times the rate of whites. In some states it’s worse: the ratio jumps to between five and seven in Michigan, Kansas, Wisconsin, and Washington D.C.
The reason black people are so susceptible as a group isn’t yet fully understood. Some have pointed their finger at the greater tendency for African-Americans to be overweight (which in turn increases the likelihood of having high blood pressure or diabetes).
But nationwide, according to the Centers for Disease Control, 42% of white Americans and 49% of African-Americans are obese. (Don’t get superior, Canada: we’re almost as fat). As Dr. Sabrina Strings pointed out in The New York Times on Sunday, that seven percentage-point disparity in obesity prevalence doesn’t begin to explain a 240 percent to 700 percent disparity in fatality rates.
The explanation more likely lies in distressing inequality, rooted in systemic racism: marginalization, grinding poverty, crowded and substandard housing, mediocre nutrition, and poor access to health care. These grim realities lead inevitably to higher rates of multiple chronic illnesses and lower life expectancy — and probably are the main drivers of increased susceptibility to COVID-19.
Increased susceptibility to COVID doesn’t cause trouble on its own; exposure is needed as well — and in New York City the poor black working class has been literally showered with virus. Many are front-line essential workers: care aides, orderlies and janitors in long term care homes and hospitals, servers and waiters in restaurants, shelf-stockers and clerks in grocery stores — settings in which the virus is easily transmitted.
Most get to work by passing through subterranean tunnels on subway cars stuffed to the gills, or by wedging onto packed commuter trains and buses — again, ideal conditions for the virus to jump from person to person to person and from thence to their families (and to the nursing home residents many of them serve.)
Doug Saunder observed in the Globe and Mail last weekend that “this pandemic is suburban”. From Paris to New York City to Stockholm, city centers have been relatively spared, while poor, lower density inner suburbs have been ravaged.
Manhattan has been left relatively unscathed compared with Queens, the Bronx, Long Island, and bedroom communities such as Rochelle and Rockland County — which is where the bulk of the working black poor live, often crowded together in run-down tenement apartment buildings.
By the time New York City locked down, many of their homes were seeded with virus, their families ripe for COVID’s grim harvest. Worse, since many of these workers are “essential”, those who seemed healthy continued to go to work, transporting virus back and forth and amplifying the outbreak with every commute.
“Social distancing” for this demographic is next to impossible. One might just as well advise a school of fish to stay dry. Social distancing is a privilege — a privilege not enjoyed, as a rule, by the working poor.
The conditions of daily life for much of Montreal’s poor black population mirror those of New York’s African-American communities in many ways, sadly. And as in New York, many black Montrealers work as care aides and support staff in long term care homes.
Also, compared with the rest of Canada, far more elderly people in Quebec over the age of 75 are warehoused in nursing homes and seniors’ residences (18 percent versus 6 percent). That disturbing situation was made even worse when elderly patients were decanted from hospitals to care homes to create space in anticipation of a COVID surge overwhelming hospitals.
It’s no surprise, then, that COVID-19 has been an unprecedented catastrophe for nursing home residents and the poor black citizens of Montreal.
Calgary is not New York or Montreal. We are not home to crowded slums of impoverished black Canadians sending hundreds of workers via subway every day to work in understaffed and overstuffed long-term care homes.
We don’t even have a subway. In a place with one-seventh the population of New York City but the same geographic footprint, the car is king. Our sprawl-and-crawl culture is nothing like that of Los Angeles, but our lack of subways translates directly into far less vectors for virus.
We have our own issues: the Cargill meat-packing plant outbreak, for instance, was the largest workplace outbreak in North America. And in one important way our experience is similar to elsewhere: the vast majority of Calgary’s 101 COVID fatalities (as of this writing) have been nursing home residents.
But on balance, the scale and intensity of viral seeding and spread experienced by New York and Montreal simply cannot happen here.
Nor is Calgary London — or Bergamo, or São Paolo, or Vancouver. The factors contributing to the heavy death toll in São Paolo differ in key ways from those in Bergamo, which are different again from those in London, or New York. The factors protecting Calgary from carnage differ in some respects from those protecting Vancouver. The virus is the virus, but every region is unique, every environment different, every population a distinctive mix. The three-legged beast is extremely complex.
Using the epidemiologic triangle to model the pandemic’s trajectory for each jurisdiction is understandably challenging: it’s a mind bending-calculus that the experts often get wrong. It’s done most confidently and most loudly in hindsight, as always, by legions of armchair quarterbacks — wizards who affirm the truth of the old Dale Carnegie quip: “Any fool can criticize, complain, and condemn — and most fools do.”
We were fortunate in Alberta to have heaps of advance warning that COVID was coming. Thanks to strong public health leadership, we took full advantage of that time.
But much of our success in flattening the curve is down to the dumb luck of of living where we do. In retrospect (emphasis on retrospect), it seems the curve wasn’t destined to be overly steep in the first place.
Instead of crowing about our “wisdom”, we’d do better to remain humble.
Better to be grateful, rather than proud.
And — as we emerge from lockdown — better to be vigilant rather than “triumphant”.
Lest the curve we’ve “steamrolled” and “chucked down the hill” bounces up and hits us squarely where it hurts.
Originally published at https://dredles.com on May 27, 2020.