When McGill hosted its first webcast on Covid-19 on February 5, the global situation was very different. That webcast, featuring infectious disease experts, Dr. Timothy Evans, Inaugural Director and Associate Dean of the School of Population and Global Health; and Dr. Chen Liang, McGill Interdisciplinary Initiative in Infection and Immunity, took place in a McGill studio, in a time when the University – and most of the world – was operating at full capacity.
Skip ahead six weeks and the world is fully in the grip of COVID-19, with countries shutting borders and imposing increasingly stringent measures to stem its spread. A sign of the times: in today’s webcast, experts were sequestered, broadcasting from their respective homes.
In the March 19 webcast, Dr. Evans was joined by Dr. Marcel Behr, co-director of the McGill Interdisciplinary Initiative in Infection and Immunity and Interim Director of McGill’s Infectious Diseases Division, to tackle pressing questions about the COVID-19 pandemic. Here are excerpts of what they had to say. You can watch the full discussion here.
Marcel Behr: The lifecycle of this virus is probably similar to that of other respiratory viruses in that it comes into our eyes, our nose and our mouth and then it finds cells in our respiratory mucosa where it enters and replicates. Viruses are not self-replicating like bacteria; they need to borrow our cells to live and replicate.
At a later point, the viruses come out of those cells and go on to infect other people. This new virus seems to be causing more secondary infections when compared to other traditional viruses like influenza. We’re not sure if this is because there is a higher viral load and people are shedding more viruses or whether there is less pre-existing immunity and so everyone is more likely to get infected because this is a new virus.
Tim Evans: There was a very interesting study that emerged from China this week suggesting that about 86 per cent of the transmission at the peak of the epidemic was likely to be due to people who were asymptomatic and not showing active signs of infection. So, this might be one reason why we’re seeing such high rates of infection.
TE: The short answer to that question is yes. I think we underestimate the shared risk that we all have in respects to global pathogens. I can’t emphasize how important it would have been for all countries to move much more quickly in ramping up their response to the virus.
South Korea has done a very good job in managing the outbreak, one of the reasons being that their test rate per million population is about 5000. If you compare that to Canada, we’re probably somewhere around 500 per million. Testing is the best way for authorities to understand where infections are, who was in contact with infected patients and where you need to direct resources to get on top of infections. Canada needs to increase its testing at least tenfold.
MB: If you’ve travelled abroad, you should be in self-isolation for 14 days. But that is very different than our current societal effort at social distancing and we can’t predict how long that will be in effect.
TE: As soon as we have tests that show whether people are developing immunity to the virus, that will help us understand whether we can relax social isolation measures. Once we start seeing that people are developing antibodies to this virus, then we can probably begin to relax some of the social isolation measures, particularly for the lowest-risk populations.
MB: When we see flu and colds, they seem to be a winter phenomenon in Canada, so there’s reason to hope that COVID-19 could be less of a summer problem. However, if that’s the case, then there’s also reason to fear that it’ll become a problem again next November. So, we’ll need to be cautious about using warmth to relax things now, if we’re not ready to ramp things up again in the fall.
That being said, if we look at Canada and Australia, countries with similar populations, the number of cases are about the same. I would submit that most places in Australia now have much more warm or hot weather than we’re experiencing in Montreal. So, I don’t see any evidence from the natural global epidemiology that it’s a cold/hot phenomenon.
MB: The measures to take are largely the same as you would have done one month or one year ago if you got a cold or the flu. If you’re feeling well enough to stay at home, then do so. If you are feeling too sick to manage at home, maybe because you have a pre-existing disease and this is exacerbating your condition, then go to the hospital.
The general indications for hospitalization haven’t changed; hospitals can offer you a level of care you cannot get in your home.
MB: My understanding is that there has been an association between ibuprofen use and poor outcomes for COVID-19. In the absence of clinical trials, it is currently unclear if this is because ibuprofen makes infected people worse or if people who were doing poorly had taken ibuprofen. But the association has been concerning enough that the WHO does not recommend taking ibuprofen because the use of the drug has no proven benefits in treating COVID-19 infections.
Since there is no demonstrable benefit, it is quite prudent to say don’t take it because there’s a potential risk. Whether its cause or consequence remains to be determined.
TE: First and foremost, we need to re-emphasize good personal infection hygiene. And that relates to hand washing, not touching our face, sneezing and coughing appropriately into elbows or tissues and keeping surfaces clean. If the household has multiple bathrooms or bedrooms, then there may be a way for the individual who is self isolating to avoid sharing certain spaces.
MB: Should a healthy and asymptomatic person wear a mask? The answer is no. When I walk to work, I don’t wear a mask. Healthcare workers wear masks if they go into a room with an infected patient or someone who we suspect has contracted the virus. There are clear directives in the health care system about who wears a mask and when, but masks aren’t for the general public.
TE: There are a few vaccine candidates that are now in phase one clinical trials, but the successful ones will also need to go to phase two and phase three, so it’ll be some time.
If all goes well with the current candidates, we’re talking a year, maybe 18 months, but it may well take longer. It’s hard to say because, as we’ve seen in the context of HIV, we’ve been looking for a vaccine for over 20 years.
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