Science

What does the COVID-19 endgame look like? Five simple steps.

Amir Attaran: Social distancing is the only option—there is no alternative. Here’s how we might eventually ease back into normal life, in a way that saves lives.

Amir Attaran is a biomedical scientist, a lawyer, and a professor in the Faculty of Law and the School of Epidemiology and Public Health at the University of Ottawa.

On Jan.  30, the World Health Organization declared COVID-19 a “Public Health Emergency of International Concern.” Since then, it caught Canada badly unprepared, and it has clobbered us. People are wondering when the misery of being cooped up at home and losing paychecks will end.  

 Obviously there is no single answer to this question.  It depends on science, guided by knowable laws, and politics, which is an ocean of human vagaries.  At worst politicians disregard science, which is true of Donald Trump’s death wish to return the United States to business as usual by Easter, come what may.  

Luckily Canadian politicians are not so insane. The path back to normalcy for us is likely to be informed by epidemiology, immunology, medicine and public health practice.  

 I write this article as a scientist to help explain what a reasonable COVID-19 endgame could look like—not to frighten, but to show that there is light at the end of the tunnel. To understand it, it is necessary to know the basics of epidemic control for SARS-CoV-2, the viral agent of COVID-19. You can read this article alone, or use the links to dip deeper into the science if you are curious.

 Every person infected with SARS-CoV-2 is a potential transmitter of infection, whether or not they are showing symptoms, which typically begin around the fifth day. Estimates vary, but each infected person is thought to pass the infection to around two or three others. This is called the basic reproductive number, or Ro, (pronounced “R-naught”) and so long as it remains above one, the epidemic is on an exponential up-slope.  

 The key to beating SARS-CoV-2 is to bring Ro down to below one and keep it there, meaning that each infected person passes the infection to fewer than one other. That puts the epidemic on a down-slope, until it flickers out. Everything—absolutely everything—else is distraction.  

READ MORE: Coronavirus in Canada: These charts show how our fight to ‘flatten the curve’ is going 

So how do you suppress Ro? There are several ways in theory, but currently only one way in practice.

While not recommended, you can pull a Trump and choose to let the virus spread like wildfire. Many would get infected and die of COVID-19—the elderly more than the young, men more than women, the immunocompromised more than the hale and hearty—but it can happen to anyone.  

Most of those who survive would acquire natural immunity to future infection, at least for a time. Once 40 to 70 per cent of the population acquires immunity this way, “herd immunity” sets in and Ro dips under one because there are few susceptibles left. We do not know this for certain, but since monkeys can become immune to SARS-CoV-2, and humans can for other coronaviruses, it is a pretty safe bet.

Another way to raise herd immunity is with a vaccine. You can buy a coronavirus vaccine for your dog, but not for humans, and no miracle can bring that about this year. Not only is that a great shame, but a testament to short-sightedness because governments lost interest in funding human coronavirus vaccinology after beating the 2003 SARS pandemic—or else a SARS-CoV-2 vaccine probably would be within reach. (Canada is guiltier of that than any other country, having pledged an initiative for a human vaccine, but so stingily that the clinical trials never began, which is also what it did for the Ebola vaccine.)

Without herd immunity or a vaccine, the best alternative is a drug that squelches the high “viral load” and risk of death in seriously ill patients, and perhaps the ability of mildly ill patients to infect others. This approach has worked brilliantly for HIV/AIDS. Trouble is, there is no drug for SARS-CoV-2, and it will take months to trial the most promising candidates. A related possibility is to transfuse convalescent plasma, which is a blood product containing the antibodies from people who fought off the infection and lived, and this too is being experimented with, though it is very hard to scale up.  

Which leaves just one option: “social distancing,” or in plain English, putting something between infected and non-infected persons to drive Ro below one.  

The “distance” could be quarantine, self-isolation, or possibly making everyone wear surgical masks in public and around sick family members. Currently we are doing the first two. We definitely cannot do the last because masks are so extremely scarce that health care workers are forced to ration them. Clearly Canada blew this preparation, and Ontario even let its emergency stockpile of 55 million masks expire without replacement. But if someday there are masks enough, some (including me) think masking up Canadians is rational and promising to try.  

And that’s the answer: social distancing is the only endgame we have. There simply is no alternative. Anyone doubting it should watch this excellent animation from the Washington Post. The question then becomes how best to do it, and later, how best to ease back into normal life, in a way that saves lives and does the least harm to society and the economy.  

Fortunately this difficult sounding task breaks down into some simple steps.

Step 1: Lock it down and test

We have to remain distanced long enough—and much harder than we are already, about which more later—to choke off viral transmission in the community. People must stay at home. Non-essential workplaces must shutter. We absolutely must lock down almost everyone in Canada until community transmission of SARS-CoV-2 plateaus and declines to virtually nil. We can lock down half-heartedly and wait months for that, or we can do it ferociously and punch through in a couple weeks—our choice. Only then will we have regained control of this epidemic, and bought ourselves a second chance to coexist with the virus in a careful way.  

While Step 1 is underway, Canada and the provinces must solve their appalling, inexcusable failure of performing too few SARS-CoV-2 tests too slowly. The waiting time for results must come down from many days to just hours, because without speedy testing it is impossible to detect and isolate infected people early, so as to spare sickness and death to their families and the community.  

All the open societies that have battled COVID-19 well, such as Singapore, South Korea and Taiwan, mastered rapid testing and reaction, because they prepared months or years ahead of Canada.  

Without a rapid testing capacity, the next steps I describe will not work, so fixing this must be among government’s highest priorities.

Step 2: Release the least vulnerable

Once Step 1 brings community transmission of the virus to virtually nil, then we can start releasing some—not all—people back into the community, one cohort at a time.  Logically we should start with the least vulnerable to severe illness, likely meaning the young, generally healthy, and not immunosuppressed, though scientists need to gather more evidence between now and then to prove these assumptions correct.  

Step 3: Keep calm and do contact tracing

Some of this cohort will become infected and sick, but that is not a disaster. Because it is a fraction of the Canadian population, our intensive care units can manage without overflowing or running out of ventilators. Meanwhile our public health workers can use their improved testing capacity on anyone showing symptoms, and move rapidly to quarantine the positives, trace their social contacts, monitor and test those contacts, and quarantine them too if necessary. That epidemiological game of whack-a-mole (or “contact tracing” in the jargon) keeps up until the last positive contacts are found, and community transmission again drops to virtually nil—meaning that it is time to move to the next step.  

Step 4: The second wave of integration

After the first cohort has reintegrated, likely taking several weeks, the economy has restarted somewhat, our health professionals have the kinks worked out, and more people have been infected bringing us a little bit closer to herd immunity—all of which means that the hardship and risk to the second cohort is less.  

Probably that second cohort consists of people somewhat vulnerable to severe illness, such as the middle aged, though I repeat science can refine the criteria between now and then. Repeat Step 3 for the second cohort, stick with the rapid contact tracing, and once again, wait for community transmission to drop to virtually nil before moving on. This round should pass faster than the first.

Step 5: The third and final wave

By now you have guessed the next step. Life is starting to resemble normal in the outside world, and it is time to release the third cohort of people most vulnerable to severe illness, likely the elderly, pregnant and anyone with an immunosuppressive medical condition.  

They are at less risk for having waited, because by now medical science probably will have learned something about saving the lives of the extremely sick. Perhaps clinical trials have even found a drug to help them through the danger. Repeat Step 3 again.

Throughout: While Steps 1-5 are playing out, no doubt scientists and hospitals will acquire an accurate, easy serological test, which determines whether a person has been infected in the past and mounted antibodies that can protect against future infection. That knowledge can be useful, for example by placing likely immune people in the riskiest jobs.

We also will need to perform routine serosurveys to determine how many people in Canada are likely immune. If our population-level immunity remains low, then extra vigilance is needed because any reintroduction of the virus, possibly by travellers, would spread like wildfire.  

But if in a year or so, the number of seropositive people reaches around 40 to 70 per cent, then we will have reached the threshold of herd immunity and the virus no longer presents a major threat. There will be sporadic outbreaks, but none that contact tracing cannot extinguish. Gradually life will become more or less exactly as before.  

At this point, we have won.

But before Canada can pull this off, Ottawa needs to beat up on the provinces that are not being helpful. The least predictable part of this scenario is where we are right now: Step 1. The longer it takes for social distancing to hit its peak, throttle Ro, and bring community transmission to virtually nil, the longer most of us have to remain cooped up or unsafe, and the longer before normal life resumes in Canada. I repeat: there is a choice of how aggressively Canada acts on social distancing now, and whether Step 1 takes weeks or months is up to us.

The holdup now is that some provinces are sabotaging social distancing for their pet industries. Ontario has declared all manufacturing and construction is essential, as if all goods are in equal demand and quarantined Ontarians cannot live without home renovations. Alberta considers the oil sands essential, although bitumen is being sold at a loss, and tens of thousands of employees from across Canada are stuffed into work camps that are superb incubators for acquiring and then dispersing infection and death to every corner of this country.  

These lagging provinces and industries, and others like them, need to be given 24 hours to change their minds, or Ottawa must use coercion including the Emergencies Act or even new emergency legislation to rein in their operations because they are putting all Canadians in danger.  

So far Ottawa has proceeded too meekly—indeed unscientifically, I would add. Unless it steps up, and puts this country on a science-based course to the COVID-19 endgame, Canada is in for a very hard ride. Ottawa bungled the preparation game. It remains to be seen if its closing game is any better.

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