The Decibel - A doctor answers your questions about RSV, flu and COVID

Episode Date: November 17, 2022

As RSV, influenza and COVID circulate, health care systems that were already strained are struggling even more. Children’s hospitals in particular are seeing a surge of patients with RSV, and departments are overloaded. As doctors expect this season of respiratory viruses to continue, many are asking provincial health officials to bring back mask mandates – which so far hasn’t happened.You – our listeners – have questions about this respiratory virus season. Dr. Leighanne Parkes, an infectious disease specialist and microbiologist with the Jewish General Hospital in Montreal, is here to answer them.Questions? Comments? Ideas? Email us at [e-mail]

Hi, I'm Mainika Raman-Wilms, and you're listening to The Decibel. With influenza, RSV, and COVID circulating, healthcare systems that were already strained are struggling even more. And you, our listeners, have questions about this season of respiratory viruses. So today, we're talking to Dr. Leanne Parks. She's an infectious disease specialist and microbiologist at the Jewish General Hospital in Montreal. And she's here to answer your questions. This is The Decibel from The Globe and Mail.

Leanne, thank you so much for speaking with me today. Thanks for having me. We're, of course, seeing a lot of cases right now of influenza and COVID and RSV as well. And recently, and this week especially, we've heard a lot about the strain that this is all causing, specifically on pediatric health care.

What are children's hospitals seeing right now? So I don't work in a children's hospital. That's my little disclaimer. But we do work adjacent to children's hospitals. And anyone that opens up their news feeds these days has seen that there is an incredible crush of emergency department visits as well as hospitalizations, including hospitalizations in some of the critical care areas within the hospital, as a consequence of acute respiratory illnesses, febrile respiratory illnesses,

and specifically illnesses related to respiratory viruses like RSV. I think, you know, coming out of a pandemic, we had a lot of strain on our healthcare system. So you had a large number of individuals that took early retirement, that burned out, that have left healthcare sectors because of just, you know, two years of unrelenting stress. So it was a little bit like a healthcare war zone that we were all in. And, you know, we are, quote unquote, shell shocked. And in addition to that, there's been a lot of budget slicing as a consequence of pandemic spending. So a lot of our resources within health care are very, very, very stretched thin. All of that together has resulted in an incredible strain on the system and would,

you know, under normal circumstances. Now we throw in respiratory virus season, which we haven't really had outside of SARS-CoV-2 for the past two years. So let's talk specifically then about this respiratory virus season. We are hearing a lot these days about RSV, which stands for respiratory syncytial virus. Just briefly, kind of on a high level term, what exactly is RSV? Respiratory syncytial virus is a respiratory virus that peaks in temperate zones at specific times per the year. So it usually starts to increase in fall and can remain in circulation or in a peak until the springtime. So what we're seeing with respiratory or what is unique about respiratory syncytial virus is it tends to

cause pretty significant disease in children. There are some individuals that are at high risk of severity, and those are predominantly premature infants, infants that have pre-existing conditions like pulmonary conditions or congenital heart disease. So in some individuals, it does create a severe infection, including bronchiolitis, pneumonia, and can cause death. So this is an infection that does have significant consequences. Yeah, okay. We asked what people want to know about what's going on right now. And lots of people seem to be wondering, how do you know if something is RSV or influenza or COVID? That's a million dollar question. The problem with these viruses is they look very much alike. So it's really difficult to determine or distinguish between the three.

So they tend to present with similar symptoms, which is upper respiratory tract symptoms. This is runny nose, headache. It can be fever. So there's certain infections that are more likely to present with high spiking fever like influenza and SARS-CoV-2. RSV can also present with high fever in children. And then there are some lower respiratory tract symptoms, which are cough and pneumonia or symptoms of those such. So the only way you really know is through testing. And we do have rapid antigen testing for SARS-CoV-2, which can provide a diagnosis. So if you were to test yourself with these symptoms of a respiratory infection and you're negative, you repeat the test at 48 hours, you're still negative. the only way you're going to know is to seek medical attention to have a molecular based test, so such as a PCR test. So knowing that you have one or the other does have implications with respect to the treatment that you might receive. For the vast

majority of individuals that are otherwise healthy, no comorbidities, not at risk of severity. The management is largely supportive and the prevention methods that you should put into or take into consideration are the same. These are all respiratory viruses. You can prevent transmission or onward transmission of your friends or to your friends of these viruses by staying at home, masking when you can't stay at home or you have to go, you know, seek attention, medical attention at a space and remaining there while you are unwell until you fully recover. Can you just help me understand why are we seeing so many cases of RSV right now? It's really interesting. So at the very beginning of the pandemic, and I'm going to blather on a little bit, so bear with me, it will come to a conclusion. When we had this novel virus, we have really no idea how to treat it, how we're learning

about it. So we implemented very rapidly and appropriately non-pharmaceutical interventions. And these include things like masks or universal mask wearing, respiratory etiquette, hand hygiene, stay at home orders, closures of schools, child care facilities. Well, the consequence of this is that it actually can prevent the spread of other viruses. And it does it very, very well because, you know, you're in a population where you might have some baseline immunity at other viruses for other viruses like influenza and like RSV. And what we saw was that it essentially halted the flu season when we implemented these. So we had this very rapid decline in influenza. And this seemed to persist for influenza and RSV for the next two years or at least the next season.

So all these measures that we put in place to stop the transmission of COVID, they also stop the transition of influenza and other viruses that we would spread around in the same way. That's what it appears to have been. So we had a drastic decline in cases. There's also a decrease in the sort of genetic diversity of the virus as a consequence of less transmission. So viruses are, you know, respiratory viruses are very unique. We see them all the time, but we don't really have this lasting immunity to them. So we get reinfected. And, you know, anyone that's lived in the pre-COVID era knows that every year you're like, oh yeah, it's another cold I got right now. And this is because of several features of the respiratory viruses. So as they transmit from

person to person, they develop small little mutations that evade our immune system. Our immunity wanes when we're re-challenged. We might get a subclinical infection or we might actually get sick again if the virus is different enough. So they're pretty, pretty smart. If you don't have a lot of those opportunities for the virus to replicate in people because it's not really around in the community, it can't make these small changes. So you just created this bottleneck in evolution. So it's pared down the virus diversity. And because of that, you might have also had subsequent less transmission. Okay, so we're getting a lot of less transmission over time here. This is very interesting. And so it sounds like this is actually building to why we're seeing a surge at this point in time.

Then how is that connected? Exactly. And then the hypothesis is that there might be a waning in your immune system. So you're not being challenged by viruses. So the sort of humoral immunity, the stuff that's made out of antibodies that can neutralize viruses at sort of your point of contact with them, that also might be declining over time. Now, if you throw in RSV, infants really rely on maternal antibodies in that first period of time to protect them. And then they're generally exposed sort of in that time, which blunts the severity of the illness. Now, during the last

two years, you had babies continue to be born, but not a lot of this virus transmitting. Plus, these infants are staying at home. They're not in child care right away. Adults in their life are maybe not having outside of household social interactions as a consequence. So we're now seeing a large population of children that have been born in the last few years that may be having their first exposure to respiratory syncytial virus. Okay, so more kids are being exposed right now to the virus. So it's almost like this cold cohort of the last two years of kids all getting it at once, essentially, instead of being staggered over time. Yes, that's the hypothesis.

Okay. I want to ask you about this idea of immunity debt. We've been hearing a lot about this idea. And the idea is that not exposing kids to viruses because of pandemic lockdowns has actually weakened their immune system. And I understand that this definition of immunity debt, when we're talking about weakening an immune system, has been pretty widely debunked. But can you help me understand why? I don't think we can say that one's immune system is now dysfunctional as a consequence of not being exposed to infections. But if you're not exposed to a given infection, you don't have the immune memory for that infection. It doesn't mean that your immune system doesn't work.

It just means that when you're first exposed, you have to develop that immune memory. That's why vaccines are really important. They give you a foot up or a head start at developing that immune memory. That's why vaccines are really important. They give you a foot up or a head start at developing that immune memory. So when you are exposed to a specific infection or a virus, then you have the ability via memory cells to create antibody much faster to neutralize that threat. We'll be right back. Another listener asked,

are things actually worse than before COVID or are we just more aware of it now? That's an interesting question. I think certainly some of our cases with respect to the rapid increase and the absolute mitigation and the processes to mitigate that. And that's been sort of the silver lining when it comes to COVID is we've learned a lot about how these viruses transmit, how we can prevent them, how our immune system interacts with them. So I think it's a combination. Let's turn to some questions around flu now, specifically. On Monday, the Public Health Agency of Canada said that we are in an influenza epidemic. What exactly does that mean? Yeah, so epidemic just means that the rates of influenza have bypassed a predefined test positivity threshold.

So our case numbers have increased beyond that threshold and they are rapidly increasing. How significant is that, Leanne? Like, is this something that happened in pre-pandemic years? Yeah, we get seasonal peaks in influenza and those are sort of our epidemics that occur on an annual basis. There are some that are much, much higher and some that are more blunted. So this is public health saying, hey, you know, we do have this virus that we haven't really thought about in two years. And now it is running wild. So this should be a time that you sit up and say, okay, now I got to suit up with my mask. I have to protect others if I'm sick. So I think in announcing this, it's not only to keep the public informed, but also to

put up that call for help that says, hey, now the role's in your hands to help decrease the spread of this respiratory virus. So this is a question from someone on our Instagram. We've seen doctors and health experts pushing provincial health officials to bring mask mandates back. So far, that hasn't happened, though they have been encouraging people to wear masks. One of our listeners specifically asked, why aren't mask mandates being brought back given all the respiratory disease? You would have to ask people within public health and politics for the reasons behind that. I am but a humble practitioner of medicine, I would echo that, yes, mask mandates or the return of masking voluntary or mandatory will be very helpful in blunting the transmission of respiratory viruses.

We know this. There's mathematical models. There's models where they use actual virus that show that masking works. And there's also epidemiology that supports it. So masks are incredibly effective at decreasing transmission for both the source as well as the exposed individual. So if everyone wears masks, you really do reduce that. Where is the most important place these days for people to wear masks? Yeah, I think this goes back to the Japanese Ministry of Health's three C's, and they were brought up by Public Health Agency of Canada as well. So these are the places that you should mask in, or you should try to avoid. So those are

closed spaces, so indoor spaces, places that are crowded, many individuals, so lack of social distancing, and places where you're in close contact with other individuals. So you're more likely to share the secretions of that individual by virtue of their respiratory droplets. So those are really places that you should mask. So anytime you're out with lots of people indoors in tight quarters, wear a mask. Okay, that's good to hear. Finally here, Leanne, you're a practicing doctor. What do you find that you have to explain most to people right now? I think there's two things. One is about vaccines and the utility of vaccines with respect to reducing onward transmission or reducing risk of severe infection for a number of different viruses and different bacterial infections. So vaccines really

do play an important role in protecting us from severe consequences of infectious disease. And they also play a really important role in diminishing the overall burden of certain infectious diseases within our community. The other aspect is really how to protect oneself when you're navigating this world, this peripandemic world where you have increased respiratory viruses. And if you have any type of comorbidity, you might be at risk for bad complications from those viruses. And even if you're healthy, you might be at risk for things like long COVID. So in those instances, my recommendations are

really vaccinate, stay home when you're sick, wear masks when you're in places that, you know, parallel with the three C's, particularly when you have sick, wear masks when you're in places that, you know, parallel with the three C's, particularly when you have high community circulation. And to really think about your community members, because each of us plays a really important role in protecting those around us. Leanne, thank you so much for taking the time to speak with me today and for answering our questions here. It's no problem. Thanks for having me. That's it for today. I'm Mainika Raman-Wilms.

Our producers are Madeline White, Cheryl Sutherland, and Rachel Levy-McLaughlin. David Crosby edits the show. Kasia Mihailovic is our senior producer and Angela Pichenza is our executive editor. Thanks so much for listening and I'll talk to you tomorrow.