[00:00:00] Jordan Heath-Rawlings: There are few things that better illustrate how well Canada is coping with COVID right now than our vaccination progress.
News Clip: Prime Minister Justin Trudeau’s one dose summer, as he termed it may turn into a two dose summer for more Canadians. Ottawa says the country is on track now to ramp up second doses.
News Clip 2: Everybody won in Toronto, uh, yesterday. Scotiabank Arena hosted a North America record for single day vaccinations. And some people-
News Clip 3: The June poll from Angus Reed revealed 88% of Canadians are vaccinated or are willing to be.
Jordan Heath-Rawlings: Over the past few months, Canada has caught up to, and then blown past every country that surged to an early lead in first doses of COVID vaccines. And now we’re taking aim at the percentage of fully vaccinated people. We are currently fifth among peer countries in that category, and we’re still gaining, but [00:01:00] we’re not gaining as fast as we were last week. And we can’t afford to slow down now. If we assume that everyone who was desperate to get vaccinated as soon as possible has now gotten their shot, that means the last few miles of this fight will be tough because most of the people who haven’t gotten their shot yet have a reason for it. Even if it’s not one that you or I would agree with. They have questions, and we know this because some of them asked us questions about the vaccines themselves,, questions about those who are not yet eligible for the vaccines, and questions about what variants might do to that number needed for herd immunity. And the answers that those people get to these questions will go a long way to determine how fast we get to that magic number.
Or if we get there at all.
I’m [00:02:00] Jordan Heath-Rawlings. This is The Big Story. Sabina Vohra-Miller is a clinical pharmacologist. She has spent most of the past year answering questions about vaccines from us, from other journalists, from people on social media. She is tireless and she is excellent at it. Hi Sabina.
Sabina Vohra-Miller: Hi Jordan.
Jordan Heath-Rawlings: The first thing that I want to ask you, because I know it’s kind of on everybody’s mind right now, as the vaccines continue to roll out. How are we doing just generally as a country compared to our peers right now?
Sabina Vohra-Miller: Yeah, I’ll be frank. Um, I did not expect to say this, but we are truly knocking it out of the park. Um, Canada wide over 75% partially vaccinated over at age 12 and over 30% fully vaccinated. Numbers are even higher for Toronto and Peel. Um, we’re actually one of the fastest vaccinating countries globally, despite having a really rough and frankly, [00:03:00] quite a late start to the game as well. But of course, momentum is sort of slowing in first doses. Um, it’s going to be much harder to take us from that 75% to the over 90% that we need, you know, so we’ve been successful in getting those who are eager to get vaccinated, as well as the majority of the originally vaccine hesitant, um, people, the ones that didn’t want to be the first, but now with billions of doses being given worldwide, confidence has increased.
Um, but now begins the difficult task basically of trying to reach those who are harder to reach. So, you know, whether it’s homebound seniors or those staunch anti-vaxxers, so we definitely cannot lose focus. Um, even though we’ve done a really incredible job so far, um, we have to continue the momentum and make sure we don’t stall the way the US stalled with second doses.
Jordan Heath-Rawlings: You just threw out the 90% number a minute ago, which is one of the things I really wanted to ask you is I’ve heard a number of different [00:04:00] thresholds for herd immunity and, you know, any number up above 80 seems great to me, but what I really want to know is where’s the threshold that we can relax almost all of our restrictions. And more importantly, that people can feel confident that COVID is not in the community and around them. And I can go to a baseball game and scream really loud, which is what I’ve been using as my threshold for normality.
Sabina Vohra-Miller: Um, okay. So the reason why you keep hearing various numbers for, you know, herd immunity it’s because the fraction that is needed to vaccinate, you know, so your herd immunity is not a static calculation. Um, it depends on the reproduction number of the virus. And it also depends on the efficacy of the vaccines.
So reproduction number, R0, is basically the expected number of cases that are generated by one case in a population. Um, so for the original of wild type SARS-CoV-2, that had an, uh, reproduction number of around two [00:05:00] or three. And with the vaccine efficacy anywhere between 70 to 90%, depending on what type of vaccine, we could have achieved herd immunity with 70 to 80% of our population being vaccinated. Unfortunately, what’s happening with Delta is that not only is the R0 much higher, the current estimate for R0 is around six to eight for Delta. Um, but if there is indeed a decrease in vaccine efficacy with Delta, then you need to immunize basically over 90, in fact, close to a hundred percent of the population to get anywhere close to achieving herd immunity with Delta. And that’s going to be exceptionally hard to get to.
And the second aspect of this is that we don’t just have to do that here in Canada. We have to do that globally. You know, we’ve seen that allowing the virus do run wild elsewhere has an impact on us as well. Um, and so, you know, it’s not just about us getting to [00:06:00] herd immunity. It’s about the entire world getting to herd immunity. So, you know, as to when we get to do things like, you know, yell really loud, mask-free at a game, or, you know, in fact blow candles at, uh, um, candles on a cake. Um, truthfully I don’t have an answer to that. I think that we sort of have to wait and see what’s happening with herd immunity and especially what’s happening with variants.
Jordan Heath-Rawlings: So you mentioned vaccine hesitant people and also just, you know, the hardcore anti-vaxxers. We’re going to get to some questions about how we can convert them or convince them maybe in a couple of minutes, but you also mentioned, you know, uh, elderly home-bound people. And I guess what I’m trying to figure out, um, of the remaining population that’s not vaccinated, where is that low hanging fruit? People who actually really do want a vaccine, they just haven’t been able to get it yet.
Sabina Vohra-Miller: Yeah. And there’s a lot of that still there. So, you know, as I mentioned, the homebound [00:07:00] seniors, um, those with mobility issues. Um, you know, those that have accessibility issues as well are having a harder time, uh, getting their dosage. Um, th the other thing that, that also tend to be missed are, are just people who, you know, I I’ll give you an example of, you know, you’re, you’re a model immigrant, basically who’s working, you know, multiple jobs in a day. Is for the most part, checked out what’s happening around because they’re so in the grind they’re trying to survive. Um, and they just don’t have the time to stop. They want to get the vaccine, you know, that, that definitely is something that they want to do. Um, but they just don’t have that, that luxury of time or resources to go get the vaccine. So there, there is quite a, quite a bit of that percentage of, you know, Um, people who still desperate to get the vaccine, we just have to make it much easier for them to get it. [00:08:00]
Jordan Heath-Rawlings: You will not be surprised to know, I’m sure, because of what I see you do on social media everyday. But we get more questions about vaccine episodes and about vaccines than we do on any other topic. So I thought if it was okay with you, we would just put a few of them directly to you.
Sabina Vohra-Miller: Sure!
Jordan Heath-Rawlings: So this is a question we got, I won’t share the person’s name, but this is a question from about a week ago. “Please do an episode about mixing mRNA vaccines. Hearing your expert breakdown vaccines is what helped me decide to get a first dose. I need some encouragement in the way of actual information, not pressure to address concerns about mixing.”
Sabina Vohra-Miller: Yeah! So you know, I’ll be honest. I think that we started the entire talk on interchangeability of mRNA vaccines with Moderna sort of having a bit of a setback because, um, people were not familiar with Moderna here in Canada. You know, we had received much fewer doses. We had tons of issues with, you know, shipment delays in [00:09:00] the early days, not anymore. Um, but because of that, Moderna wasn’t able to, you know, gain that familiarity and confidence with people the way Pfizer did. And it was really interesting because in the US, the opposite was true and that people were clamoring for Moderna in the US, you know, because of high profile celebs, like Dolly Parton, Dr. Fauci, um, you know, who, who both received Moderna and many, many others.
Um, but you know what it really comes down to between Pfizer and Moderna is that they both code for the same spike protein. Um, so both of them have mRNA sequences that are very, very, very similar. Um, they’re obviously not identical, but, but here’s the thing. Um, you know, you’re actually coding for the entirety, for the full length of the spike protein, not just a small section of the spike protein, which the earlier iterations of the vaccines, um, you know, we’re doing. The current vaccines that we have the code for the [00:10:00] entirety of the spike protein. So when you do that, and you create the antibodies against them. You’re actually creating very, very, very similar antibodies between Pfizer and Moderna. Your body does not actually recognize brand names, your body recognizes antibodies and they both create the exact same, or very, very, very similar antibodies to both of them.
And, and I think that, you know, for the most part, I think it’s just the whole conversation about interchangeability because it’s such a novel topic for people. It’s something that we’re talking about so much has got so much airway. But here’s the thing, people actually interchange vaccines for tons of other diseases, for tetanus, for influenza, Hep A, Hep B, Tdap, you know, pretty much every vaccine we have on our roster, we have, we have several different brands for each of, um, each of these diseases.
And we actually just don’t know what we’re getting. You know, when we go to the doctor, when you go to your GP and you’re getting [00:11:00] your booster shot, you don’t ask what brand name, booster shot you’re getting for your Hep A or your Hep B vaccine, you just get it. Um, and it’s really interesting because I’m actually in the process of exporting my son, who’s going to junior kindergarten this fall, exporting his vaccine record to the regional public health, um, online. And I’m looking at all the vaccines he’s gotten and he hasn’t gotten the same vaccines for all of his boosters, you know? But who looks at your vaccination card to see what you’re actually getting?
And it’s the same with influenza. You get a different one for every booster that you get every year. So, you know, uh, interchanging vaccines is a very common concept. We do it for tons of other diseases. We are just not aware of it. And so I think it’s just the, the unknown that makes people more concerned about the interchangeability. Um, really, there is no reason to believe that mixing would have any significant concerns with safety, or in fact on efficacy either. So I don’t think there’s much to be concerned about.
I think it’s just information [00:12:00] overload where people are bombarded with this and it’s making everyone more anxious about their decisions. I, I would, I have zero apprehension. I mean, of course it’d be nice to have clinical trial data on this. Um, but really there, I am not apprehensive about, um, mixing and matching the two mRNA vaccines whatsoever. And in fact, Dr. Theresa Tam, who is our Chief Public Health Officer of Canada got Pfizer for her first dose and Moderna for her second dose. So if anything, you know, that should be generating more, um, confidence amongst, uh, Canadian people.
Jordan Heath-Rawlings: I’m glad you had such a thorough answer for that. And I hope you have one for this too, because this is actually something we were emailed by a listener, but something that I also think about a lot. And given that you just mentioned that your son is headed to junior kindergarten, just like my daughter, I bet you think about it too. So the question is, “What do we know about when/if children under 12 can get vaccinated? I know it’s still June, but it feels like the [00:13:00] clock is ticking to return to school already, and I’m worried.”
Sabina Vohra-Miller: Yeah. Great question. And I totally understand that. Um, so we’re expecting to see data for the five to 11 age range sometime this fall. Um, we will most likely have approval before end of the year. But that, you know, obviously still leaves the under five age group. You know, I think that those who have kids in the five to 11 age range, um, you know, should feel confident with the fact that there will be approval most likely much before end of this year. Um, those with kids under five, it’s probably going to be a little longer, but that is why it is exceptionally important for everyone else who is the vaccine eligible to get fully vaccinated with two doses, especially because we, you know, are in the midst of, um, Delta being the predominant strain here in Ontario, elsewhere in Canada as well. Um, and so if we can [00:14:00] actually get everyone else to the point where they’re all vaccinated, um, that is going to be exceptionally important to try and protect the children who are still unvaccinated and protect those who are immunocompromised.
Jordan Heath-Rawlings: This is just me being curious now, but when you’re looking at vaccines, like the mRNA ones, what are the concerns about putting them into children younger and younger? And what are you looking for there that you may be weren’t looking for in the 12 and ups or the eighteens and ups?
Sabina Vohra-Miller: So, you know, with, with, um, with children, I think that what we have to make sure, first of all, is that we’re not giving them a dose that is much larger than what they should be receiving, especially for mRNA vaccines. We know that they’re very immunogenic. Um, they can be very reactogenic, i.e. You can have like, you know, immune side effects from them. And we know kids do have a very robust immune response as well. And so we want to make sure that the dose we’re giving them, um, does [00:15:00] not put them at a higher risk for having side effects.
And so, as we’re seeing, you know, with the mRNA vaccine, vaccines there, we are seeing reports of myocarditis happening, you know, in a, at a higher incidence rate in younger people than, than we see them in older people. Uh, you know, partially this is because myocarditis tends to occur in younger people more often than older people anyways. So that is, You know, in general, but you know, so we want to make sure that things like myocarditis, there’s not any, you know, it’s not higher, um, in, in, in younger children. And if it is then should do we have to look at different dosages? Do we have to look at different durations? Do we extend the interval on this population?
These are all things that we have to look at. So we need to make sure, first of all, that the dose that they’re getting is the right dose for their age group. Um, and then we have to make sure, in addition to efficacy that there’s no other safety issues that are occurring, um, with these [00:16:00] vaccines in children.
Jordan Heath-Rawlings: You mentioned that Delta is now becoming the predominant strain in Ontario and in the rest of Canada. We’ve gotten a couple of questions about how we know that the current vaccines are effective against Delta. As you mentioned earlier, I think it can be really intimidating to see so many different numbers claiming to represent the same thing. So what do we know about vaccines and Delta?
Sabina Vohra-Miller: I think what we know for sure at this point is that having two doses or a complete series of vaccination is key for Delta. And so, you know, it goes back even to the conversation on mixing and matching mRNA, if you’ve got Pfizer for your first dose and you’re not able to get Pfizer for your second dose, um, the, you know, the only bad decision in that, in that scenario would be to not get a second dose or delay your second dose. Um, and, and that’s because getting two doses is so incredibly important, um, against Delta. We have some [00:17:00] data showing that, um, efficacy or effectiveness against, uh, against Delta, symptomatic Delta with one dose is only around 33% for both AstraZeneca as well as for Pfizer, but it jumps up to 60 and 88%, um, for AstraZeneca and Pfizer respectively.
And, you know, I think that what we need to also keep in mind is that. What we’re seeing now in UK and Israel is that Delta is highly transmissible. In fact, it’s at least 50% more transmissible than Alpha, which itself was 50% more transmissible than the original wild-type. Um, what we’re trying to understand right now is whether Delta can escape immunity. And if so, to what extent does it do that? Um, we see a decrease in neutralizing antibodies, but we don’t anticipate any changes in T cells, you know, which is your other half of immunity.
And so what we we’ve been seeing so far until last [00:18:00] week was that, um, the vaccines were exceptionally effective against symptomatic disease against Delta. Unfortunately, today, you know, I don’t know if you’ve come across, but there’s been a lot of, um, you know, the new reports have come out basically today from UK and from Israel that is showing even lower vaccine effectiveness against Delta.
Jordan Heath-Rawlings: Yes. I was going to ask you about this.
Sabina Vohra-Miller: Yeah. So around 60%. So, you know, what, what, what we saw, what we’re seeing, um, in Israel in UK is that the efficacy seems to have, for symptomatic disease, seems to have dropped from like high nineties to sixties. But the efficacy against severe illness still remains high at over 90%. Um, and so that is extremely reassuring. Like, of course, you know, hospitalization and deaths are lagging indicators, but we would have seen something by now and we have not. So, you know, that is extremely reassuring.
Um, what we are also seeing is that, you know, a large percentage of the [00:19:00] cases are in those who are unvaccinated. In the cases that, of the people who are vaccinated, we’re not seeing a subsequent increase in severe illness or hospitalization in them.
Um, the other thing also, you know, I think that sometimes headlines can be misleading and the reason for that, you know, it’s called base rate fallacy. Um, so first of all, we know that no vaccine is a hundred percent efficacious, right. And so if you have large percentage of your population, That are vaccinated. The number of cases in the vaccinated will increase. That’s just bound to happen. Um, so what, when I, when I mean base rate, when I say base rate fallacy, what I mean by that is that say for instance, you have a population of a hundred people and every single one of them has been vaccinated. You have a hundred percent vaccination rate in them. You ended up having one case of breakthrough COVID. So while you only have one case, it translates to a hundred percent of COVID infections are in the vaccinated. That’s your base rate fallacy. And you’re going to see more and more of this as higher [00:20:00] percentages of the population get vaccinated.
But the bottom line on Delta is that, you know, yes, we still need more data, but so far what we’re seeing seems very reassuring. It does mean however that we have to continue to ramp up second doses like that is absolutely non-negotiable, we need to make sure we’re going full steam ahead with getting everyone their second doses. But it also means that we have to be, you know, more vigilant. We have to continue doing some of our non-pharmacologic interventions to protect those who are vulnerable in our communities, such as those who are immunocompromised, they may not actually mount an adequate, um, immune response, um, with even despite being vaccinated. And then of course, children who are not able to be vaccinated yet. Um, so I mean, it looks good so far. We need more data to come out, um, on this, but I am very reassured by the fact that even though you’re seeing more symptomatic cases off of COVID with those who are vaccinated, [00:21:00] they tend to be generally mild illness.
Jordan Heath-Rawlings: Sabina, thank you so much for taking the time to explain all this stuff to us again, we will probably get more questions after this episode airs. So maybe we’ll check back in with you later this summer.
Sabina Vohra-Miller: Absolutely. I’d be more than happy to, thanks for having me.
Jordan Heath-Rawlings: Sabina Vohra-Miller, clinical pharmacologist, the best smart person to ask dumb vaccine questions to. That was The Big Story, for more head to thebigstorypodcast.ca. Find us on Twitter, ask us questions. We will try to get them answered. We are at @TheBigStoryFPN. If you don’t want your question public, just email it to us. We’ll leave you anonymous. The address is thebigstorypodcast, all one word, all lowercase, @rci.rogers.com [click here!]. And anywhere you get podcasts, you will find this program. If they let you, leave us a rating, leave us a review.
Thanks so much for listening. I’m Jordan Heath-Rawlings, we’ll talk tomorrow. [00:22:00]
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