COVID-19: Predictions From Canada’s Top Expert on Aging and Immunity


Dawn Bowdish, the Canada Research Chair in Aging and Immunity says we may see a return to some semblance of normal life in June-July, but that another wave of the coronavirus is expected in the Fall. Photo: Courtesy of Dawn Bowdish

Feel like you’re becoming an armchair expert about COVID-19?

From flattening the curve to serology, we’ve had a crash course in virology as SARS-CoV-2, the virus that causes the respiratory illness, spread to all corners of the world in a matter of months.

We know the basics: wash your hands frequently, stay two metres away from others and cough or sneeze into your elbow, or wear a non-medical mask to contain your respiratory droplets, which is how the virus spreads from infected people — whether they are feeling sick or not. And now we know just how hard social distancing is on both the economy and, more importantly, on us psychologically.

But what about the more complex aspects of the pandemic? Why are people over 60 at higher risk for severe illness? How do we protect people in nursing homes? And how long will COVID-19 affect our lives?

For insight, advice and the science we talked to Dawn Bowdish, the Canada Research Chair in Aging and Immunity at Hamilton’s McMaster University. But she admits that, even for the experts, in some cases, the answers are still a best guess.

Experts warn of possible outbreak waves after the first one ends. Why?

“If all goes well, there will be a winding-down, and our lives will return to some semblance of normal in June-July. But we are expecting a fall outbreak as we lift measures of social distancing and travel sort of starts up again. It’ll be a new normal but it won’t be normal. And unless there are major changes, then we expect that there might be periodic outbreaks in 2021 as well.”

So, will COVID-19 circulate like the flu or die out like SARS did?

“It does not look like the flu in that it doesn’t mutate enough so that every year we need a new flu [shot]. It doesn’t mutate at that rate.

“It’s unlikely to die out like SARS did. If you think about the enormous measures we have to take to get this under control and about all the countries in the world that don’t have those kinds of resources and have infections that probably will be higher than what we currently have in Canada, there will be pockets all over the world until we can really globally come together to stamp this out. And so travel will continue to be a major source of outbreaks.”

When a vaccine is available, will everyone get it from now on, like childhood inoculations?

“It depends on what we learn. It’s important to remember that most vaccine trials fail. So I’m heartened by the fact that there are so many different trials trying so many different approaches all over the world. And the hope is that we’ll get a vaccine, like a measles vaccine, that actually protects almost everybody almost all the time.

“However, it’s more common to make vaccines that give partial protection, like our influenza vaccine. The hope is certainly that we develop a gold-standard vaccine that will protect everybody all the time, but we should prepare for other challenges, such as vaccines that only provide partial protection or maybe just make the disease less serious in vulnerable populations.

“But I don’t think we can expect it to be completely eliminated in a year’s time. That would be an unrealistic expectation.”

Why, generally speaking, can’t older people fight COVID-19 as well?

“We are really good as we get older of bringing back what we call memory responses. A great example of this was the 2009 H1N1 pandemic. Intriguingly, people in nursing homes weren’t dying off of this virus, but younger people were, and it was because many of those [older] people had been exposed to a similar virus 67 years prior.

“However, in cases like COVID or some seasonal influenza outbreaks, those require a totally new immune response to be made. And as we get older, we’re not very good at doing that. The reasons for this are complicated but they come down to the fact that our hematopoietic stem cells, the ones that make our white blood cells, are less productive. As well, there’s a lot of inflammation in our body as we get older, and our immune cells respond to that inflammation, and sometimes this makes them less functional.

“One of the work-arounds for vaccine development for influenza, for example, has been using what we call a high-dose vaccine, and that seems to protect older adults a little bit more. It’s unclear whether we will need a similar strategy with COVID-19. [But] even if older adults don’t respond very well to a vaccine or aren’t totally protected, if everybody else in the community becomes vaccinated, then there are fewer people the virus can infect and, indirectly, this will protect older adults. ”

Older adults with underlying health conditions are at higher risk of severe outcomes. What can they do?

“Let’s use diabetes as an example. People who have really huge swings in their blood glucose tend to be the ones who are most likely to get pneumonia or to be hospitalized for other infectious diseases. For viruses, it’s really not clear why, but we know that immune health sort of increases with blood sugar control.

“We know that people with cardiovascular disease can be at higher risk, and some of it is because heart disease increases inflammation. So people who are really proactive in managing their heart disease, especially if they’re combining [that with] exercise and a healthy diet, the lower that inflammation is. And when inflammation goes down, immune function goes up.

“People who manage their chronic conditions are really managing their inflammation, and that then helps the immune system do what it needs to do when it comes in contact with a new threat.

“One of the things that we’re finding out as the epidemic hits North America is obesity also seems to be a bit of a risk factor. Obesity causes a lot of inflammation and immune changes. It’s very similar, from an immunologist perspective, to premature aging. So we think that that might be why heavier people seem to be more at risk.”

I’m seeing lots of “Take these vitamins and minerals to boost your immune system.” Do supplements help?

“Once upon a time, we were all very excited about vitamin C, but it’s failed in many clinical trials. It’s been shown that vulnerable patients — people with COPD and other chronic health conditions — who take a lot of A and E are actually at higher risk of respiratory infection than people who don’t.

“There is sufficient evidence that says if you’re in the Northern hemisphere — we are almost certainly a little bit vitamin D deficient — supplementing with vitamin D does seem to prevent serious respiratory infections. We have no idea if that’s the case for COVID-19, and it will take us a long time to figure that out. But if you felt compelled to take a supplement, that’s the only one that the science really supports.”

Is there anything else older adults can do?

“Physical distancing is extremely important because they are vulnerable. However, exercise is also really important. And if it is safe for them to go out and take a walk and get some of that vitamin D naturally, that’s really important because being sedentary is particularly problematic for older health.

“I really do worry about all these older adults being stuck in front of the TV all day because they can’t really go out. So I would encourage them, even if it’s just doing weights or trying to do some squats, try to work some exercise into your routine.”

We’re hearing a lot of heath experts talk about antibody, or serological, tests. Why?

“These sorts of [blood] tests are considered the most reliable measures to figure out how many people have been infected by a virus because they will detect people who’ve been asymptomatic as well as symptomatic. They’re extremely valuable in understanding the spread of the virus within the community. They’re also extremely valuable because the hope is that people who have generated these antibody responses will have some protection from the virus. So maybe those people are safe to go back to work or maybe to be in higher risk situations.

“Canada is being extremely proactive in developing these, and I expect that certainly within the next few months, we’ll see them starting to be broadly implemented.”

What’s the difference between serological and PCR tests to confirm COVID-19?

“Our current tests measure the virus directly by swabbing the back of the sinuses and measuring the amount of viral nucleic acids by PCR [polymerase chain reaction]. It has a low false positive rate when there is little virus, like at the beginning or ending of an infection. Essentially, these can only be used to detect if you are currently sick.

“An antibody test generally uses blood, but some people are looking into saliva and measures antibodies specific to the virus. This can measure if you have ever had the virus, we think — antibodies might disappear after a year or two. But generally there are not antibodies in the first five days of an infection. They are about as easy, although some people hate giving blood, others having the back of their sinuses swabbed, but answer slightly different questions.”

You’ve said before that we will learn from outbreaks in nursing homes. What good will come from what we now know?

“One of the silver linings, I hope, is limiting part-time work in multiple long-term care/nursing homes. Many workers have to work more than one job and potentially bring infections with them. This has led to deaths from influenza and other illnesses but not quite as dramatically or visibly to the public.

“Once we’ve had some sober second thought and looked at processes in place, we’ll probably realize that there were ways that could have prevented this. So maybe one care worker only works with rooms A, B, C and a second worker only works D, E, F, and there’s no transfer between those rooms. It’s expensive to do that but it’s absolutely essential in these kind of vulnerable populations to make sure that workers aren’t the vectors for transmission.

“If I could change anything, it would be offering more long-term care workers stable full-time jobs that include infectious disease awareness and decent sick leave so people don’t go to work sick.”

You and your team are perhaps busier than ever. How are researchers staying safe?

“I’m working primarily from home as much as I’m able. And my lab members, we’re really limiting the amount of work we’re doing in the lab and trying to be really, really, really safe. So only people who are working directly on COVID projects are currently allowed to be working in the lab. Even then, we’re trying to make sure we do our best social distancing and have people wear protective equipment if they need to be close to someone.

“It’s been challenging to manage but it’s so important that we’re part of the solution, not part of the problem.”