Why expanded testing will make it harder to assess the economy’s reopening,
Ontario’s lockdown being eased as testing ramps up, which could skew picture
On this long Victoria Day weekend, millions of Ontarians are enjoying a new level of freedom as the government begins to ease up on some of the coronavirus restrictions in place since early March.
In the first stage of the government’s reopening plans, beginning Tuesday, some health facilities will resume surgeries that had been delayed by the lockdown, retail stores with street entrances can open, some parks, marinas, golf courses and recreational activities will be allowed and construction projects will be resumed.
But the manner in which the government has chosen to roll out its reopening has made it that much more difficult to monitor the effects of the easing of public health restrictions.
At the same time, the provincial government eased up on its coronavirus restrictions, it also announced that it would expand testing for the coronavirus. Moving forward, testing guidelines will be widened so anybody with COVID-19 symptoms can be tested.
But that creates a problem in tracking the spread of the disease.
“We’re basically reopening at the same time we’re expanding testing,” said Ashleigh Tuite, an epidemiologist at University of Toronto’s Dalla Lana School of Public Health. “We’ve created a bit of a challenge for ourselves in terms of looking at the daily numbers.
By changing two variables at the same time, Ontario has made the data picture going forward murkier. Numbers of cases will increase in the next few weeks, but epidemiologists will have a difficult time telling what proportion of that increase is due to expanded testing and what proportion is due to the effects of relaxing restrictions.
Ideally, she said, the government would have introduced expanded testing a few weeks earlier, enabling epidemiologists to establish a baseline on the new testing criteria. If restrictions eased after that new baseline had been established, epidemiologists would have been able to attribute any change in case numbers solely to the easing of restrictions.
“It’s an appropriate move,” Tuite said. “And I’m glad that it’s happening. It just muddies the waters a bit in terms of trying to look at trends.”
To clear those waters somewhat, she suggests that epidemiologists would be more likely to focus on the number of new patients in hospitals and ICU’s and mortality cases, as a measure of the success or failure of the more lenient restrictions.
But that carries a caveat: Much like looking at a star, when epidemiologists track COVID cases, they’re looking at things that happened in the past.
“We’re probably going to want to keep a closer eye on hospitalizations and ICU occupancy, with the challenge that those are delayed,” Tuite said.
“So if we start seeing those increase, that suggests that those are transmission events that happened a week or two ago. So it’s a little bit of a lagging indicator, but I think it’s probably going to be something that’s more appropriate to watch, given that the testing has changed.”
But a further problem is that the provincial government has not been very clear on the criteria for determining the success or failure of this first stage of the reopening.
“There hasn’t been a lot of talk about, ‘How do we know if this isn’t working?’ When do we call it? When do we say that we tried this, and transmission is increasing — we’re seeing more cases in the community? What is the point at which we say, ‘OK, we have to dial this back,’ ” Tuite said.
While the government has said that “key public health indicators will guide when Ontario progresses to the next stage,” it remains non-specific about what that means in terms of numbers for any of the familiar metrics: COVID cases, hospitalizations, mortality, rates of transmission, and so on.
Questions to Ontario’s Health Ministry on this subject were diverted to the Finance Ministry.
“Public health experts will carefully monitor each stage so we can benefit from best practices and lessons learned throughout reopening,” said Finance Ministry spokesperson Scott Blodgett, in an emailed statement.
“If the gradual reopening in Stage 1 is successful, Ontario can move forward to Stages 2 and 3. Otherwise, public health measures will need to be adjusted and/or tightened. The government will continue to plan for what comes next and provide more details on each stage when ready.”
Asked what role the Finance Ministry would play in whether or not the province progressed to the next stage of reopening, and whether there were financial criteria that would affect that decision, Blodgett did not respond.
Ontario chief medical officer Dr. David Williams has previously set a benchmark of fewer than 200 new infections through community spread as a criteria for progressing to the first stage. It is unclear if the same benchmark applies going forward.
Whatever the criteria are for determining success or failure in the current stage of the province’s reopening, it seems certain that there will be an uptick in COVID-19 cases in the next few weeks.
Dionne Aleman is a professor of industrial engineering at the University of Toronto. Her research involves developing pandemic models to simulate infectious disease outbreaks in urban environments, first during the H1N1epidemic, and now with COVID.
She said success or failure in the first stage of the province’s reopening will largely be determined by people’s behaviour.
“Generally, in a pandemic, the second wave is worse than the first wave,” she said. “Once things start to get relaxed, there are actually lots of people that are infected, but maybe very mildly so, or currently asymptomatic, and they just go out and quickly intermingle with lots and lots of people.
“And that’s why you see suddenly a huge spike for the second wave. Whereas the first wave started with only a very small number of people being infected, the second wave starts because lots of people are infected.”
Typically in second waves, she said, epidemiologists will see a greater number of infections, and also a higher rate of infection.
That said, most of scientists’ knowledge about pandemics comes from — most recently — the SARS pandemic and H1N1, both of which were not very widespread. The next closest source of knowledge comes from the Spanish flu in1918. But many things have changed since then.
“Even just in terms of contact, tracing, managing the population and communicating with individuals in the population … we are able to communicate with everybody and explain to them, “This is what’s expected of you,’ ” Aleman said.
“Hopefully, just that information alone will mean that we sort of bucked the trend in expected second waves that we’ve seen in historical pandemics … and that will still put a damper on the usual very large second peak.”