Canada

'Am I at risk if I pass someone on a crowded sidewalk?' (and 11 other coronavirus questions)

Infectious diseases specialist Dr. Isaac Bogoch on immunity, recovery time, which countries are beating the virus — and what's up with France's war on Ibuprofen

The number of confirmed coronavirus cases worldwide has now reached more than 750,000, with Canada making up about 7,700 of that total. Measures have become even more stringent in the past week to address the rapid spread of the disease, including banning people who show symptoms from travelling domestically by air or rail, and the indefinite closure of ‘non-essential’ stores, businesses, and public recreational spaces across the country.

But as infection numbers multiply, so do questions about the nature of a COVID-19 infection, recovery time, and the efficacy of some protective measures. Maclean’s asked Dr. Isaac Bogoch, an infectious diseases specialist at the University of Toronto, to debunk some coronavirus-related myths and provide guidance on how to navigate necessarily stringent rules on social isolation. This transcript has been edited for length and clarity.

Q: If you’ve contracted the virus and have recovered, are you immune?

A: We’re not entirely clear, and we don’t have all the answers, but it’s very likely that people will be immune to this virus if they have recovered from an infection.

The issue is that we know viruses change with time, and that’s called mutation. One of the concerns is; Will this virus over a period of time gradually mutate to a point where people who have recovered from their infection may no longer be immune? We see this with influenza, as the virus changes consistently.

Q: What about people who are said to be ‘asymptomatic’ carriers of the virus? What do we know about them?

A: We don’t know a ton about this scenario. The more appropriate word to use is, ‘subclinical.’ When we say someone has a subclinical infection, their symptoms are mild enough that they’re below the detection of the health-care system, meaning that whatever they feel, they’re not sick enough to seek health care.

We know there’s likely a significant proportion of people that are infected that are subclinical. There’s a growing database of young children having a greater proportion of subclinical infection.

The concern is that these individuals can contribute to transmission of infection in community settings … even if they’re less likely to transmit infection (because usually people with fewer symptoms shed and transmit less virus), and they’re not being identified, they’re not isolated.

Q: Do we have a sense of how many are subclinical?

A: We don’t.

There’s shreds of evidence pointing towards big numbers, anywhere from 20 or 30 per cent, but I’m not confident in that data, and I’m looking forward to seeing data from multiple sources to shed light on that.

Q: What is the range for recovery? For some people it seems to be a few days, for others, weeks.

A: The rate of recovery will be completely dependent on how ill one gets in the first place, and this is going to be a massive spectrum.

From the mild end of the spectrum, we know that some people may recover in a day or two. Of course, we know there’s the complete opposite of the spectrum. Some people have critical illness or are cared for in an intensive-care unit (ICU) and are gradually released from hospital when they recover. The recovery from those cases can be protracted.

The issue, sadly, is if someone has a severe enough illness to require to be put in an ICU, there’s data from other cohorts looking at people who recovered from Acute Respiratory Distress Syndrome that suggests a significant proportion of people are not at their baseline level of function even five years after discharge.

In general, those who aren’t that ill and are out of hospital, I think it’s reasonable to expect they will make a complete recovery over a period of days, or sometimes weeks. For those in the ICU, it can be a much longer ordeal.

Q: How do you know when someone who has recovered can return to being around other people?

A: There’s different criteria in different parts of the country, and globally there’s different mechanisms for determining this.

Some people will say we want two negative swabs separated by 24 hours to tell us you are clear of this infection. Other people are saying, when your symptoms disappear, you’re going to wait x number of days before you’re allowed to take yourself out of home isolation. And that number of days differs by jurisdiction. So there’s no true consensus on what that actually means on a global level.

Q: Some claims on cures and remedies have come out since we last spoke. Namely, France’s health minister said people with coronavirus should stay away from Ibuprofen (Advil) as it worsens symptoms. Where did that claim originate? And is it credible?

A: There’s theoretical data that may suggest that part of the metabolic process for Ibuprofen and part of the metabolic process for COVID-19 infection may interact with one another. But there has been no data to suggest this has any real world implications to date.

It’s interesting, because in medicine we don’t use a lot of Ibuprofen. Many of us, if we’re treating a fever, would gravitate towards Acetaminophen. Many of the patients we see have other health reasons (not coronavirus related) to why we avoid Ibuprofen. But of course, this has to be individualized to the patient.

Q: There’s new claims surfacing daily. Where do you get your most trusted, up-to-date, medical information on the virus?

A: I typically scour the high-calibre medical journals for quality information.

The ones I read closely include, but are not limited to, the New England Journal of Medicine, The Lancet and its sub specialty journals, the Canadian Medical Association Journal, the British Medical Journal, and the Journal of the American Medical Association. These are great journals that publish terrific research and also interesting opinion pieces as well.

Good resources for people in Canada include the provincial public health websites, which I think are excellent, and the Government of Canada and the Public Health Agency of Canada websites. They have up-to-date data, plus up-to-date information on what to do and what to expect. For more of a global perspective, the World Health Organization has a good website as well.

You’re getting good information, you’re not getting snake oil on those sites.

Q: When it comes to Canada’s response to COVID-19, are there any gaps you can point out?

A: In general, I think as a country and as provinces, the response has been very good.

Obviously, it’s still early in Canada and we cannot get complacent and we don’t yet know the true, full impact of this pandemic, both on a health standpoint, an economic standpoint, and a sociopolitical standpoint. It’s just too soon to tell.

My two areas that I would improve on are: rapidly expanding diagnostic testing in the out-of-hospital setting, and ensuring there is more than an adequate stockpile and supply chain for personal protective equipment for frontline healthcare workers. If there are issues with the supply chain, then there should be rapid enrolment of Canadian industry to make or buy it.

We need to continue this push and we need to continue to have leadership from our senior health and public health officials to essentially keep our foot on the gas pedal to promote physical distancing and also promote access to testing.

Q: Which country’s response do you admire so far, and what can we learn from them?

A: There’s several countries that I think have done a remarkable job on this. The few that come to mind include South Korea, Taiwan and Singapore.

South Korea was starting off on a pretty tough trajectory with a rapid increase in the number of cases, and it looked like it was spreading very quickly, but they were able to pivot and get their epidemic under much better control. Taiwan took this seriously from the get-go. They’re right next door (to mainland China), but they sent a delegation to Wuhan to assess the situation early on and they realized this could get out of hand quickly and started implementing control measures.

One of the interesting things Taiwan did is they harnessed technology, and they were able to track people they were concerned about to make sure they would adhere to isolation protocols. They had excellent public health messaging. They were very good at scaling diagnostic testing, and they were very good at identifying infected individuals but also close contacts of those individuals. They also supported people for those 14 days at home, because not everyone has the same social safety net.

Q: Some public health officials alluded the virus may be cyclical in nature, and we may have several waves of cases through the seasons. What do you make of that?

A: The short answer is we don’t really know yet. These are all theoretical situations and this is all speculation.

We do know that coronaviruses tend to like the colder months, and the thought is perhaps after this pandemic starts to wane, this might not completely go away and we might see this COVID-19 infection emerge in the cooler months, just like influenza does.

Whether or not that pans out, no one really knows. This is why so much effort is being placed on finding a vaccine.

Q: We’ve noticed that grocery stores have put up plexiglass. Does that work as a barrier?

A: Employers are doing their best to protect people that are still having to go to work, and whatever we can do to make people have a safer work environment, especially for people who have essential jobs who work in grocery stores, I think it’s totally reasonable.

If people are coming to public places infected with this virus and perhaps coughing or sneezing, that’s completely unacceptable to do, but it’s still a possibility. And things like (plexiglass) may help mitigate any risk that these employees have. It doesn’t eliminate the risk but it’s one barrier between them and the general public, which might be helpful.

Q: People are trying to get some fresh air by going on walks. But sidewalks can be crowded and it’s difficult to maintain a two-metre distance. Are you putting yourself at risk if you pass someone at a close distance?

A: Any situation where there’s lots of people crowding together is not a situation that people should be in, and we should be avoiding that at all costs.

But we know that if you’re practicing physical distancing measures, you could be walking on a trail or a sidewalk where it’s impossible to have that two-metre distance. I think that for the fraction of a second people are walking by each other, that’s still a very low risk situation.

We’re aiming for perfection, but of course we can’t adhere to these strict guidelines for every nanosecond of the day, and there might be fractions of a second here or there where people come into our close radius. Some situations are unavoidable, and we just have to live with it.

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