Expert Explainer: Dr. Nitin Mohan on circuit breaker lockdowns

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Some experts in Canada are considering a ‘circuit breaker lockdown’ to help control the surging case counts of COVID-19.

Dr. Nitin Mohan, Assistant Professor at Western University’s Schulich School of Medicine & Dentistry, is a physician epidemiologist who teaches in the Master of Management and Applied Sciences and Master of Public Health programs. He explains the pros and cons of circuit breaker lockdowns.

What is a circuit breaker lockdown?

A circuit breaker lockdown is a lockdown with a set start and end date. It is different than the lockdowns we saw during the first wave, where we were looking for case-counts to drop below a certain threshold before restrictions were lifted.

What exactly is involved in that shutdown depends on the government. We’ve seen certain places around the world like Australia that have had a strict lockdown. Generally, when we talk about strict lockdowns we are referring to many parts of our economy and sectors that are shut down, reducing the chance of human to human transmission. Some examples include: school closures (less preferred), closures of bars, nightclubs, gyms and takeout-only options for restaurants and the implementation of curfews. We’ve also seen some places that have had a soft lockdown, where there isn’t a lockdown in all parts of the economy and every sector. So really, it comes down to how aggressive a government wants to be.

Are there examples of it being a successful strategy?

There are examples of circuit breakers that have been successful in Wales, Northern Ireland and Germany. We can also look at what happened in Australia, but there they locked down for 100 days and a typical circuit breaker would shut down for 18 days to a month at the most.

In order for circuit breakers to be successful, there have to be additional measures that need to take place. Part of locking down also has to involve building up testing, contact tracing and capacities in the lab settings, which has to happen simultaneously with the circuit breaker lockdown.

In addition to a circuit breaker where sectors of the economy and the public are shut down, people also have to stay home and not have close contact with others outside of their household. Because we now know the virus spreads through close contact with other people, the challenge is figuring out how to actually prevent people from going to see one another.

We have seen that if people isolate for ten days after symptoms, they are no longer infectious, so you could see a situation where if we isolate long enough — for 18 days — our case counts should drop.
However, the concern is once we lift the circuit breaker lock down, cases will rise again, so we have to make sure we use that time wisely to build capacity where it’s needed.

Do you think circuit breakers are the answer to getting case counts down in Canada?

I’m not sure if circuit breakers are the answer in terms of what it will take to get the numbers under control in Canada. I think we need to break it down by province because there are a lot of nuances by province. Some provinces are hubs for international travel - so we see that in Toronto, Montreal and Vancouver, and it makes things a little more difficult than provinces that don’t have these international hubs.

We have some more data on circuit breakers now, and there is data that looks at what a 14-day lockdown looks like versus an 18-day versus 28-day and there are considerable drops in infection rates. With lockdowns that take into account a ban on public events, school and workplace closures, stay-at-home requirements and limitations on internal movement, it has been noted that R has been reduced by 35 per cent on day seven, 42 per cent on day 14 and 52 per cent on day 28. R is defined as the time varying reproduction number, which is the average number of people one infected person will pass the virus to.

So, we know there is some level of effectiveness there. That being said, that effectiveness is not for the entire population and appears to protect some while leaving others at risk. Our economies are held together by essential workers who are often times our most vulnerable members of society. If our lockdowns require these integral members to continue risking their well-being to support the rest of the system, we leave them exposed to bear the burden of this pandemic. So how do we create a system that is equitable for everyone and protects everyone?
What we do know is that we need to control the virus first and the economy will bounce back after. That’s easier said that done. There are folks that are bearing the brunt of this and they are typically minority individuals and those who are vulnerable in our society. So if we are going to lock down, we need to provide supports for small businesses and provide economic supports for essential workers.

There is also a movement called COVIDzero that looks at eliminating COVID case counts within an area right down to zero. That movement is gaining momentum.

The ultimate goal is to drive case counts down as low as possible and while doing that we need to increase our testing capacity and contact tracing and invest heavily in public health and acute care.

Why hasn’t the death rate surged this time around the way it did in the spring?

We are seeing rises in case counts here in Canada, and our death rates aren’t where they were in the first wave, and when you first hear that, you could mistakenly think we are doing better than we were in the first wave.
The reality is that we do have some therapies available this time, such as dexamethasone, that we didn’t have during the first wave, and we have more data and more time with the virus.

That being said, we are starting to see our ICU capacity being filled up again in Ontario. There is a threshold that we can hit and it becomes very dangerous because once those capacities are filled, there won’t be space for patients who are in motor vehicle collisions or have heart attacks and other injuries that require ICU services.

I think we have to be very cautious in saying the death rate is perceived to be lower than it was in the first wave. We’re seeing deaths in long-term care homes, and we’re seeing marginalized and vulnerable populations bearing the brunt of this virus, and I think it’s important when we talk about circuit breaker lockdowns or any sort of modality, we have to have a heightened lens on this demographic.