The Current

'Totally irresponsible' to expose yourself to COVID-19 in hopes of immunity, warns immunologist

Immunologist Jeanette Boudreau explains how immunity works, and why it would be irresponsible to try to get COVID-19 in the hopes of developing resistance.

Immunologist Jeanette Boudreau says we can’t be sure exposure will lead to immunity

A man walks past a COVID-19 alert sign in Vancouver's downtown eastside Thursday. (Jonathan Hayward/Canadian Press)
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More than a thousand Canadians have recovered from COVID-19, but there are still questions over whether recovery guarantees immunity, or how long such an immunity would last.

That uncertainty lies in "the fact that it's a brand new virus," said Jeanette Boudreau, an immunologist and an associate professor in the Department of Microbiology and Immunology at Dalhousie University.

She spoke to The Current's Matt Galloway about how immunity works, and why it would be "totally irresponsible" for someone to expose themselves in the hopes of developing resistance.

What do we know about people who have recovered from COVID-19? Are they immune against further infection? 

We don't know for sure. It's a brand new virus. The likelihood is that the answer to the question is yes, because that is what happens with other coronaviruses, and for that matter, all the other viruses that we know of out there.

Jeanette Boudreau said that even if recovering from COVID-19 does bring immunity, it's not clear how long that immunity would last. (CBC)

But we do not want people … to go and hang out with other people, perhaps who have coronavirus, just to develop that immunity?

No, absolutely not. That's a terrible idea. We saw early on in this outbreak that it was the elderly and the immunocompromised that seem to be at greatest risk. 

But as time is moving forward, we're seeing more and more that people who are otherwise in excellent health are ending up in hospitals. Our healthcare systems are already overwhelmed as it is with the outbreak that's happening naturally. So it's totally irresponsible to go out and try to get infected. 

How do researchers go about establishing whether somebody is now immune?

The test we most often do for a virus ... [is to] measure for a protein in the blood called an antibody. Antibodies are made by the immune system after it's been trained to see a particular pathogen.

We can take the coronavirus itself, we can break it down into its proteins and see whether we have reactive antibodies. So it's just a simple blood test, we look to see whether those antibodies are present or not.

What we know scientifically is that those antibodies are important for neutralizing the virus. So they keep the virus from being able to infect new cells.

It starts out looking like a regular flu. But when the virus attacks lung cells, shortness of breath ensues, says family physician Dr. Peter Lin. 0:27

What we don't know yet is the quality of those antibodies. Some people have antibodies that are really fantastic and other ones have antibodies that … don't work as well as they could. Maybe they help to make the infection — that would otherwise be really severe — more mild, but they still might not protect. 

The other piece that we don't know is how long the protection is going to last. Things like the SARS coronavirus, which was pretty severe, that immunity seems to be pretty strong, on the order of a few years. For the more garden-variety coronaviruses that we get and just sort of shrug off as colds, it only lasts for a year or two.

I was reading about researchers in New York who say that they are almost ready to try transferring COVID-19 antibodies into patients who are critically ill with the infection. Is that because they think, to your point, that maybe there is the possibility that those antibodies could help neutralize the virus?

That's exactly it. This is something that worked in the Ebola outbreak, most recently in 2014 [and] 2015. Essentially what they're doing is giving these patients a shortcut. It takes about a week to make your own antibodies. But if you can get the antibodies on site earlier, maybe they can stop the virus from infecting more and more cells, and causing more and more damage, and get people sort of over that hump.

By now, you likely know not to touch your face. But if you do suspect you've already caught it, reach out by phone for assistance, says family physician Dr. Peter Lin. 1:02

If you are trying to get to a point of immunity, how does the mutation of the virus affect that?

It depends on how the virus itself is mutating.

There's parts that are critical. So they have to do with how the virus actually makes copies of itself or how the virus attaches to cells. And there's a lot of pressure on the virus to not change those.

Those are what you want to mount an immune response against, but of course our immune system doesn't know what that is. If the virus mutates in a way that allows it to escape the immune recognition, then the immune system has to go back to the beginning and start over with a new response.

There's been a lot of talk about different approaches to try to develop a vaccine or perhaps use existing things that might work in this different scenario. How hopeful are you when you hear of that research?

In the long run, I think we will end up with a vaccine. I know of at least five different approaches being taken by different groups around the world. All of those approaches in principle work. They've worked for vaccines for other other viral infections, they've worked in animal models, the only kind of catch is that we haven't figured out how to make them work for COVID-19 yet. And that, again, just speaks to the fact that it's a brand new virus.

Canada's Chief Public Health Officer Dr. Theresa Tam says social distancing measures not only help flatten the curve of COVID-19 cases, but also buys time for research and innovation to happen.  1:09

What would you, as an immunologist, say to those people who might be complacent when it comes to that idea of physical distancing?

The virus can't move itself. If you make it so that the virus can't get to its next host by staying far apart from each other, then you really are doing something that's important to buy us the time we need to make the vaccines, and figure out how to treat this.


Written by Padraig Moran. Produced by Alex Zabjeck.

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