Note: Transcripts may contain errors. If you wish to re-use all, or part of, a transcript, please contact CBC for permission. Please check the corresponding audio before quoting in print. Copyright © CBC 2024

The Dose Transcript for February 29, 2024

Host: Brian Goldman

BRIAN GOLDMAN: Hi, I'm Dr. Brian Goldman. Welcome to The Dose. Measles cases around the world are on the rise, something I'd hoped I'd never see, including countries where vaccines are readily available. Here in Canada, cases have been identified in Quebec, Ontario and Saskatchewan, and I fear we may be coming to a tipping point like we're about to let the measles genie out of the bottle. So this week on The Dose, we're asking, how can I protect myself and my kids from the measles? Hi, Zain. Welcome back to The Dose.

ZAIN CHAGLA: Thanks for having me, Brian. Great to be here.

BRIAN GOLDMAN: You know all about measles, which is why we've come to you. Have you ever seen it?

ZAIN CHAGLA: Not in Canada, but in some of my international work, I've seen a few cases, and it can be pretty devastating for kids.

BRIAN GOLDMAN: Yeah. And you know what, I'm old enough to remember seeing cases of the measles. I had it, so we want to talk to you all about that. Can you give us a hi, my name is? Tell us what you do and where you do it.

ZAIN CHAGLA: Hi, my name is Zain Chagla. I'm an associate professor at McMaster University and an infectious diseases physician and one of the medical directors of infection control at St. Joseph's Health Care in Hamilton. And I spend my days doing clinical infectious diseases as well as health systems planning for infection control.

BRIAN GOLDMAN: So remind me and tell everybody who has never seen the measles or measles before, what exactly is measles?

ZAIN CHAGLA: So measles is a viral infection caused by measles virus. And this is an infection, realistically, that is one of the most infectious in terms of spread pathogens known to man. So the virus transmits sometimes on surfaces, but mainly through respiratory contact in the air. The virus can remain infectious in the environment for up to two hours after someone has left that environment. The virus then takes root in the lungs and then leads about 10 days later to the characteristic symptoms that people get and lead to, unfortunately, complications that come from it.

BRIAN GOLDMAN: Let's talk about how contagious it is. My understanding is that any one person who is infectious, if they get close enough to other people and they're all breathing the same air, could infect as many as nine or 10 other people.

ZAIN CHAGLA: The reproductive rate can be coded up to 20. So that really means that, you know, a single person can lead to 20 secondary infections. And it's because of this infectivity, not only is it infectious, you know, when that person is in the room with someone else, but this virus is infectious even when that person has left the room. And there's lots of really interesting literature. I'll give you an anecdote. There's a case series that got reported in Minneapolis in St. Paul's, associated with a Special Olympics that was held a couple of years ago, and essentially, someone who is in the opening ceremonies of the games infected someone that was sitting in the upper deck of the stadium.

BRIAN GOLDMAN: Wow!

ZAIN CHAGLA: So you can imagine how far apart those two people are. But they were able to see that those two people, despite having no contact with one another other than being in the same stadium at the same time, were able to infect each other.

BRIAN GOLDMAN: To be clear here, you know, we're talking numbers, but that makes measles way more contagious than COVID, right?

ZAIN CHAGLA: Absolutely right. And this is where there has been so much work done with measles, recognizing that and the fact that we suspect much of the population that's older than a certain age has seen it in the past because it is so infectious that it's almost an expectation people would get it, but truly is one of the most infectious organisms known to man.

BRIAN GOLDMAN: What are the symptoms?

ZAIN CHAGLA: Traditionally in medical school, we get taught the four Cs. So cough, cariso, conjunctivitis and Koplik’s spots, which is actually a K. So typical cough, cariso, which is runny nose, conjunctivitis. You know, unfortunately, the problem with this disease is that while people are infectious, they're experiencing these symptoms. All of us have experienced a cough and a runny nose at some point in our lives, probably at some point in the last year. But it really does look, unfortunately very early on, like a number of other respiratory illnesses. After that point, a few days later, the characteristic rash emerges. And so this is a rash we call maculopapular. So spots, red spots that start on the face start becoming much more apparent on the face, to the point where they almost form a single layer of redness going down into the neck, and then goes down the rest of the body at that point. And that's where most individuals make the diagnosis. The problem with this virus, along with all the stuff we talked about earlier, how it's highly infectious, is that people are infectious before the rash starts. And so you can imagine, you know, someone with a mild runny nose and a cough, relatively feeling okay, being out in public, being with others, you know, not necessarily seeking medical care upfront because of the fact that they look like they have the common cold. It's only until the rash shows up, which is actually towards the end of the infectivity of this illness where they finally have characteristic symptoms, that then prompts health care attention, where unfortunately, the exposures have happened and it's too late. So another one of the reasons why this spreads so quickly is that, you know, people are very mildly symptomatic for some time while they're infectious to others.

BRIAN GOLDMAN: And I can remember my pediatrician mentors at SickKids in Toronto, where I did an internship in pediatrics, we actually saw kids with the measles. And the pediatricians who were teaching me said, look behind the ears for the first appearance of the rash, the spots. And by the way, they're not only raised, they're painful. They're not itchy, they're painful. Now, cases have also appeared in the United States and Canada, which is the major reason why we're talking about this right now. This is a clear and present danger. Where are the outbreaks that you happen to be keeping an eye on right now?

ZAIN CHAGLA: So I mean, this is complicated because of the fact that there has been ongoing measles activity in a number of places in the world that have had a number of different reasons associated with it. So in low income and middle income countries, due to, you know, ineffective vaccine campaigns, so no fault of individuals, but the fact that we can't reach people with vaccinations, particularly in rural and remote settings, there has been ongoing measles transmission and outbreaks of measles that's occurred chronically. And so, you know, for example, I did a lot of my training in Eastern Africa. And, you know, certainly, it was not uncommon to see measles cases amongst children. And not to any fault of their parents, but the fact that they really didn't have access to vaccines. The alarming trend has not only been that, which is something that, you know, globally, there is a need for significant support for, but we are also seeing measles show up in high income settings where routine vaccination is standard, where access to health services is standard. But for a number of reasons, people are not getting vaccinated. So, you know, there have been outbreaks that have been increasing in Western and Eastern Europe. That then has led to essentially transmission that has become endemic. So not only have individual cases occurred, but there has been ongoing spread through regions, which, you know, then presents even further challenges. So as we talk about measles and particularly, you know, the need for vaccines and the need for updates, the other contributing piece here is that this has really become, for Canadians, a travel associated disease. And it's not simply travel to low income and middle income nations. This is travel to places in Western Europe which are fairly common for Canadians to visit and unfortunately, are still areas where measles is transmitting.

BRIAN GOLDMAN: So they acquired measles there and then brought it to Canada where they were diagnosed. Now, more recently, in the last little while, we heard about an outbreak, an actual outbreak in Florida where a bunch of kids were found to be infected, and it was probably some evidence of person to person spread there. We're keeping a close eye on that situation. Has there been any evidence of person to person spread in Canada yet?

ZAIN CHAGLA: Unfortunately, there's not much published about the cases. There's certainly a significant amount of exposure associated with these cases, and this is not uncommon, particularly as we talked about the symptoms being fairly mild. So people that are out in public, often going to commercial settings or as the disease is progressing, they're going into different health care settings until someone recognizes the syndrome. From what I understand, there has not been person to person spread. But absolutely, there is a cluster now in Fort Lauderdale, Florida, which, you know, Canadians know is a pretty common destination during the winter where a number of children are infected. That seems to be centred around a school, but there does seem to even be transmission outside of that school. So, you know, concerning that it's spreading on soil. And we've seen this before. You know, about five, six years ago, there was a large outbreak at Disney World in the United States, again in Florida, where children were infected at Disney and in fact went back around the country back to their homes and led to local transmission. So unfortunately, these events, these one-off events, thankfully, we were able to contain them because of the fact that we have good immunity and fairly aggressive public health intervention for these cases. But it is a matter of time before one shows up in the wrong community, the wrong place where immunization and the immunity rates are not high. And that certainly can lead to local transmission, which creates even more challenges for containing the disease.

BRIAN GOLDMAN: So we're talking about a disease that was very close to being eradicated from the planet maybe 20, 25 years ago. And that ship has unfortunately sailed. You've started to paint the picture, low vaccination rates in some communities. But why are we more at risk that an arriving passenger with measles could start an outbreak in Canada? What are the factors that are going on now compared to, say, a few years ago?

ZAIN CHAGLA: Part of it is an acceleration of what happened a few years ago. As many know, there was a paper that was published with a potential link between regressive autism and the measles vaccine, which has been essentially retracted, and a number of systematic reviews, databases, whole country data suggesting that there is no link whatsoever. Unfortunately, that paper, you know, has left long lasting hesitancy in certain communities. And parents who did not immunize their children, some of those children now are parents themselves and are making the same decisions for their children. And so you now have a cohort of people that's increasing that has not accessed vaccine despite it being available.

BRIAN GOLDMAN: Then came COVID.

ZAIN CHAGLA: Then came COVID. Exactly. And so we see two things that happened during COVID-19. One is, as we all experienced here, health systems were challenged, and many people had to pivot into a COVID-19 response. Access to routine immunizations came off for people that were very willing to get it. But for the access to primary care and the issues that came from it, people lost their vaccines and are now starting to catch up from it. So certainly, rates have gone down from that piece. And again, you know, vaccine hesitancy, particularly with the vaccines that came out with COVID-19, also increased. And so we have a number of people that may have been on the fence about childhood vaccines, where COVID-19 vaccines then increased their hesitancy, that are again choosing to reduce their vaccines for their children. And then globally and, you know, again, the reduction in health systems, you know, one can't discount how important the vaccinations are in low and middle income countries. And unfortunately, due to a significant issue with health care utilization during this time, as well as, you know, escalating conflicts in many areas of the world, this unfortunately has led to generations of children not having access to vaccines. And knowing how infectious this illness is, the natural result is the measles virus will find individuals that are not vaccinated one way or another in these settings.

BRIAN GOLDMAN: Hospitals, public health units are trying to help parents catch up their kids on their routine childhood immunizations. Wise public health officials have told me that we want the population to be 95% immunized against measles. That would all but shut the door on a traveler arriving with measles and starting a local outbreak. Where are we? How far down from 95% are we right now, do you reckon?

ZAIN CHAGLA: First, it's important to mention that this is a two dose vaccine series. And that's another issue with public health that is concerning in that many individuals have gotten their first dose of vaccine. About 91 plus percent. There is a drop off, though, in people that have gotten two vaccines. Some of that is not intentional. So when measles vaccines were introduced into Canada in the early 80s, it was recognized it was a single dose vaccine series. And then we did see some breakthrough cases occurring and two doses were kind of brought to the front. By 1996, two doses were standard. But you can understand there is a cohort of people from 1983 to 1996 where their initial advice was to get a single dose of vaccine. No one has really reached out to them to get a second. Some of those folks are adults now, and so they're not necessary going to the pediatric system. And so those folks are some of the target for some of this public messaging to really make sure that they understand they should be getting their second dose. So that is part of the concern. But part of the concern is people that have not got their first dose or parents who have chosen not to get their first dose as part of their child's immunization series. And, you know, 91% is reassuring. And thankfully, you know, with these cases that have shown up to Canada, we haven't seen spread, which is a testament to our wall of immunity. But as that wall chips down a little bit more and a little bit more, we are going to see local spread. You just have to look to Western and Eastern Europe, places that had high immunity, high vaccine rates that are seeing resurgences in measles that is actually transmitting locally even throughout the year. We're not different than many of those settings in that context. And the principle is there that it could transmit if our immunity wall comes down.

BRIAN GOLDMAN: Can you talk about your date of birth and how that has a bearing on whether one dose or two doses of the vaccine provide adequate protection for you?

ZAIN CHAGLA: We recognize, I think, that people prior to a certain age probably did have measles.

BRIAN GOLDMAN: That is me. Yeah.

ZAIN CHAGLA: Yeah, exactly. And so, you know, it's not a perfect number, but the 1970s. So people that are now 53 years of age and older would be considered in an era where measles was circulating globally, and they likely would have had it, you know, in their childhood diseases or at some point in their life. It's not perfect. And so we recognize that. And even in those individuals, we still recommend a dose of vaccine to bridge the gap, unless they've had laboratory confirmed measles in the past, where that immunity probably carries through their lifetime in terms of getting another measles infection. So that one dose is really just an extra insurance plan for those folks to make sure that, you know, they're protected one way or another. In people after 1970, measles stopped circulating, and that's because of the global vaccine campaign and improvements in hygiene and housing. And so those folks who are born after 1970, so under 53 years of age, we don't expect to have seen measles at some point in their life. They may have, but this is where the two dose vaccine series came from. So folks in that age group typically would get a vaccine at year one and at year four to six. Again, some of those changes even happened after that. So in 1983, routinely at age one, and then 1996, routinely a two dose series. So there's people that between 1970 and 1983 that may not have been offered a vaccine that should be considering getting it, people between 1983 and 1996, where they may have gotten one dose of vaccine, but not a second, and then, you know, thankfully, people after 1996, where they should be up to date, have got the full vaccine series, according to the province. But you can see where it's a bit complicated and recognizing that people now in some of those age groups are adults, they may not have their vaccine records. And so it's imperative for them, particularly if they're travelling or going into high contact settings, to really make sure they're up to date. And if they're not, just getting another dose of vaccine for the context of being absolutely certain that they're protected from measles with their two doses of vaccine series.

BRIAN GOLDMAN: So when we talk about whether or not you need one dose or two doses or whether you're effectively covered, you're immune, we're talking about a concept in public health known as presumed immunity. And it's predicated on the notion that measles doesn't keep changing like influenza or like COVID has. Is that still true? Can you or can you get measles more than once?

ZAIN CHAGLA: It's incredibly rare, probably case reports, but yes, we presume that someone with laboratory confirmed measles infection can’t get measles again. In reality, nothing's 100%, but close enough to it. Similarly, if someone with a two dose of a vaccine series is nearly 100% protected against exposure to measles, again, nothing is 100%. There are breakthrough cases very, very rarely, but usually, again, in people that just don't make great vaccine responses, not necessarily in people that are otherwise relatively healthy. The complication in all of this is that history of measles. So for yourself, it sounds like you had a good history. But we all understand that children born 1970 or older may have had some viral illness as a child associated with a rash, whether or not that was chickenpox, measles, some other viral exanthem like roseola. And so establishing that history isn't always easy. And this is where the single dose of vaccine has really come from to say, okay, if we don't really have a good history, even though we think based on epidemiology, you are exposed, that we optimize your immunity and kind of move on from there, recognizing, again, the more immunity in the population, that wall of immunity really is what keeps endemic spread of measles going forward.

BRIAN GOLDMAN: And if you've inadvertently gotten a third dose, it's not going to harm you.

ZAIN CHAGLA: Not at all. And this is the measles, mumps and rubella vaccine. So for example, women of childbearing age, they get screened for rubella because we want to prevent rubella in children. And if their titres are low or undetectable in pregnancy, they will get an MMR vaccine at the end of their pregnancy after they deliver because we want to make sure their next pregnancy, they're protected. So there are many different populations where they may get an additional dose of an MMR vaccine in adulthood. And again, as long as people have a good immune system that's allowed to take live vaccines, they can absolutely get that booster dose down the line.

BRIAN GOLDMAN: I want to move into the subject of somebody who's got the early symptoms, or they have a pretty good idea they've been exposed to somebody who was diagnosed with the measles and they want to seek attention from their health care provider. What should they do?

ZAIN CHAGLA: First and foremost, absolutely. It's important to seek help, especially if people do not have adequate immunity to measles. So they haven't had their vaccine series. The reason being is that we can actually immunize people after exposure to prevent them from getting measles. It's such an effective vaccine that if you give it to people very early after their exposure, you can actually abort measles with getting a vaccine right then and there. And for other patients who are immunocompromised, we also have antibody products to replace that because they can't get the vaccine as part of post-exposure prophylaxis. So, you know, number one, keep tabs on what's happening in your community. Because these settings that have measles exposures are pretty broad, public health will put out notices. So just keep in touch with it. Number one. Number two, if you think you've had an exposure, worth it to reach out to kind of say, you know, especially if your measles immunity is not up to date, to say, is there anything I should do if you're immunocompromised? And then if you start developing the characteristic symptoms, again, we have testing appropriately, whether it's done by a nasal pharyngeal swab, by urine, by bloodwork. But you really want to in advance tell your provider, whether it's your primary care provider, an emergency room, an urgent care, to let them know that you are worried about measles.

BRIAN GOLDMAN: Yeah.

ZAIN CHAGLA: Because we want people to be seen safely, but we need to institute infection control precautions in order to prevent any spread in those settings. So people get isolated, they're wearing a mask, the providers have the ability to then also wear their mask and appropriate personal protective equipment, and so that if we diagnose the measles, that there is no secondary exposure in those settings, recognizing how infectious it is and how, unfortunately, emergency rooms see such broad populations, some of which may be immunodeficient and may not have, you know, a good antibody response to their prior vaccines.

BRIAN GOLDMAN: March break, it's coming up. What steps should travelers take to protect themselves against measles infections related to travel?

ZAIN CHAGLA: Travel is a great opportunity to talk about all of your vaccines, not only measles vaccines, what you need for travel, staying up to date on your other vaccines. So, you know, it's worth it if you're travelling, to just have that discussion, or look through your vaccine records and see if you're not up to date with something and go for it. But particularly for measles, especially as, again, it's transmitting in many settings that Canadians visit during March break, it's important to look through that piece of whether or not you've had two doses of the vaccine if you're younger than 1970, one dose of the vaccine if you're older than 1970, and really prioritizing that a couple of weeks prior to your travel, as it does take time for that vaccine to work. And again, if you return from travel with the appropriate symptoms, give people a heads up that this might be measles so that the appropriate testing is there. And you work in an emergency room. I think our emergency room, we've done a ton of education just to make sure that we're capturing people appropriately early, right at triage, so they're not exposing others. But again, keep tabs on your symptoms. Call a health care provider if you do develop symptoms, particularly the rash. And again, you can be seen and tested, but we just need to do this in a careful and controlled manner.

BRIAN GOLDMAN: Finally, timewise, measles, you know, a lot of people considered getting the measles as a child a rite of passage. This is not a benign disease, is it?

ZAIN CHAGLA: When it was a childhood disease, I think, you know, a lot of people got it. We may know that one person that, you know, had complications, but the majority did fine. The more we learn about measles, it is a dangerous virus. So number one, measles itself can cause its own problems. It can infect the brain. It can cause brain injury. And there are children that have sequelae of hearing loss and developmental delays because of their measles infection. Number two, measles is very peculiar because it actually causes an immunodeficiency afterwards. So people's immune systems may make a great response to measles, but may make poor responses to some infections they've seen in the past. So they then are at risk of bacterial pneumonia, ear infections, herpes infections, which can lead to blindness. Those children have significant complications afterwards. And not only children. Adults who develop measles as well, despite them having good immune systems, they can lose them as part of their measles infection temporarily. And the third thing, and this is what I saw while abroad, is especially in certain populations that were at risk, measles causes malnutrition. And it is devastating for children sometimes, the amount of protein they lose and the consequences of malnutrition in them. And so again, this is not a disease you want to give a very young infant who is already trying to deal with gaining weight. And leading to milestones early, malnutrition may set them back, may lead to developmental delays, and not something a parent wants to deal with in the context of healthy childhood for their children.

BRIAN GOLDMAN: Dr. Zain Chagla, thank you so much for bringing us up to speed on measles. Thanks once again for coming on The Dose.

ZAIN CHAGLA: Always happy to be here. Thanks for having me.

BRIAN GOLDMAN: Dr. Zain Chagla is an infectious diseases specialist with St. Joseph's Health Care in Hamilton and an associate professor at McMaster University. Here's your dose of smart advice. Measles is a highly contagious disease caused by the measles virus. The symptoms include fever, cough, runny nose, red eyes, spots inside the mouth and a red, blotchy rash that starts on the face and spreads to the trunk and limbs. Typically, the rash begins on the third to seventh day of illness and lasts for up to seven days. You are contagious before the typical rash appears. The virus spreads through the air and can survive in the air for several hours. Each infected person can in turn infect nine, 10, or up to 20 people who are susceptible. See your health care provider if you think you or your child may have measles. Because it's very contagious, call the clinic in advance so they can take special precautions to protect other patients. To prevent measles, you need to get vaccinated. Children receive their first dose of measles, mumps and rubella vaccine, or MMR, at 12 months and the second dose at age four to six years. Children and teens who have not been vaccinated at all should receive two doses of MMR vaccine a minimum of at least four weeks apart. Adults born on or after January 1st, 1970, should have two doses of MMR. If they've only had one dose, they should receive a second dose. Adults born before January 1st, 1970, are generally assumed to have gotten measles and are therefore considered immune. If you aren't sure you got measles, your health care provider can do antibody testing, or you can get one dose of MMR vaccine. Measles has serious complications such as pneumonia. One out of every 1000 get encephalitis or inflammation of the brain, which can result in permanent brain damage, and one out of every 3000 die from respiratory or neurologic complications. This is one virus you don't want to risk. If you have topics you'd like discussed or questions answered, our email address is thedose@cbc.ca. If you like this episode, please give us a rating and review wherever you listen. This edition of The Dose was produced by Sameer Chhabra. Our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm Dr. Brian Goldman. Until your next dose.

Back To Top »

Provide Transcript Feedback

CBC would like to acknowledge the support of the Broadcasting Accessibility Fund.

How can I protect myself and my kids from measles? - Transcript

More Stories Like This