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COVID-19 lessons from a Ryerson epidemiologist

Professor Tim Sly has been sharing information through BSE, SARS, H1N1, and now, COVID-19
By: Jessica Leach
March 27, 2020
An illustration of two people drawing a circle around themselves, with images of a virus floating around

Professor Tim Sly wants to remind the Ryerson community that social distancing will help the healthcare system manage cases. Photo credit: iStock.

Now, more than ever, we are relying on experts to help us understand diseases like COVID-19 and the risks they pose. The more we know and understand, the easier it will be for us as a community to practice self-isolation and social distancing in order to flatten the curve.

We asked Tim Sly, an expert in epidemiology, and a professor emeritus in the School of Occupational and Public Health, to help us understand his expertise and how it applies to COVID-19 and social distancing.

What is an epidemiologist?

The modern epidemiologist is a specialist in the methods and factors that contribute to ill-health, injury, illness and mortality. They also study how to avoid, reduce, or eliminate those risks. The range of applications is very wide.

What is the easiest way to describe what they do in circumstances like this?

We are encountering a novel coronavirus (COVID-19), in the early stages of a global pandemic. There is much to study about this disease and this agent. Epidemiologists are studying how it is transmitted, the risk factors, susceptibility, communicability, and the calculations used to describe and model the spread, and predict the future course that the pandemic will take, so that communities and society as a whole can be better prepared.

You were involved in research during the SARS crisis. How does COVID-19 differ?

Both are coronaviruses, and share about 85 per cent of the genome. SARS was more likely to cause death for an infected person (about 10-11 per cent), compared to COVID-19, which will probably be found closer to 1 per cent. COVID-19 spreads at a faster rate. SARS was never a true pandemic, because it affected only certain locations outside of China, such as Taiwan, Hong Kong, Singapore, Toronto. Worldwide SARS caused 8,000 cases, and as we’re seeing, COVID-19 has grown well beyond that in number of cases and locations.

Where does the idea of social distancing come from?

Canada and most countries are in the exponential phase of the epidemic curve. Cases are doubling, sometimes every 3, 4 or 5 days. A pandemic of an acute viral respiratory illness can be expected to infect between 20 and 40 per cent of the population. Social distancing is the only way that the hospitals might be allowed to operate, by slowing the rate of infection, flattening the epidemic curve, and spreading the cases over a longer period.  There is the social disruption but it allows medical treatment to continue. It may also reduce the incidence slightly.

What do you want the Ryerson community to know?

Do NOT under-estimate the potential of this illness. We are in the pandemic of the century, closer in potential to the 1918 A/H1N1 pandemic influenza, which, until now, is on record as having brought about more deaths in one year than any other plague or illness in the human experience. The “stealth” aspects of this virus are becoming especially more concerning; As many as 30-40 per cent of positive-tested people may be asymptomatic.

Politicians still appear reluctant to inform the public just how many cases are likely, how many hospitalizations can be expected, and how many deaths we should be preparing for. What we have seen in Italy (who were late instigating social distancing), could happen here. It is already happening in Spain, Iraq, and in many other regions. Think months, not weeks. We may still be in some form of pandemic response by the end of the year unless severe restraints are made now. 

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