Ep. 62: What Can I Do After My First Dose? & Other COVID-19 Questions

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COVID-19 provokes all sorts of questions. Can I see my grandchildren after the first dose? How does the first vaccine shot affect risk of severe COVID? When will vaccinations push down ICU admissions? Every week Medcan’s Medical Advisory Services team of expert physicians get together to discuss trending topics. They develop advice to share with their corporate clients, which include some of the world’s biggest brands. The docs are witty, and the meetings entertaining, but more to the point they feature up-to-the-minute guidance of the sort that we’re all craving. So we recorded one of their sessions and cut it into an episode.  

Featured in this show is (clockwise from above left) Medcan chief medical officer Dr. Peter Nord, clinical director of travel medicine Dr. Aisha Khatib, senior medical consultant Dr. Matthew Burnstein, associate medical director Dr. Jason Abrams and Dr. Alain Sotto, who, in addition to his role at Medcan, is also the occupational medical consultant for the Toronto Transit Commission.

To enlist the services of Medcan’s Medical Advisory Services, email corporatesales@medcan.com.     

INSIGHTS

It’s not yet known how likely a partly or even fully vaccinated person is to transmit the coronavirus, says Dr. Aisha Khatib. “So we really still need to maintain those public health measures to help decrease the risk of entering into a bigger fourth or even fifth wave down the road.” Plus, Dr. Nord says, no vaccine is 100% effective. “We're assuming that there is a reduced transmission with vaccination, but we don't know that for sure.” In other words, some risk will remain that even the fully vaccinated can transmit the virus. (5:00)

The variants of concern continue to live up to their name. According to Dr. Alain Sotto, case fatality rates have tripled among 20-29 year olds for those in Brazil infected by the P.1 variant, from 0.04% to 0.13%. Dr. Nord points out that an outbreak of P.1 is ongoing in British Columbia and that, while the vaccine does appear to be protective against current variants, some risk does exist for future variants to require additional vaccination measures. (7:25)

Speaking about VIPIT, or the Vaccine-Induced Prothrombotic Immune Thrombocytopenia associated with the AstraZeneca and Johnson & Johnson vaccines, Dr. Jason Abrams puts the relative dangers in perspective. Risk of blood clots is higher for those taking the oral contraceptive pill, or those who smoke, compared to the blood clot risk from the AstraZeneca vaccine, Dr. Abrams says. “Frankly a lot of people are not getting the AstraZeneca vaccine—they are waiting,” agrees Dr. Nord. “And what people have to understand is that there’s risk associated with that as well.” (9:30)

Rapid antigen tests like the Abbott Panbio, which provide results in about 15 minutes based on a nasal swab, should be one of the mainstays of preventing outbreaks at workplaces, says Dr. Alain Sotto. The test protocol also provokes questions from the curious. People are wondering: Will those who have been vaccinated produce a positive result on a rapid antigen tests? The answer, Dr. Sotto says, is no. Later, Dr. Khatib says that rapid antigen tests will detect cases that are too early in their infection cycle to be symptomatic. In fact, she argues that screening with the tests may have prevented the Amazon warehouse outbreak. (13:15, 16:50)

More clarification about what you can change after you get your first dose: According to Dr. Sotto, the first dose provides about 80% efficacy in the real world. Dr. Nord clarifies: About 80% of the people given their first doses did not receive any symptoms of COVID-19 infection. But unfortunately, Dr. Burnstein says, the first shot does not change your behaviour. Internally, the first dose makes people feel less anxious about getting infected, because they are more protected than they were before. But externally they shouldn’t change their behaviour at all. (23:00)

Dr. Khatib serves in a COVID-19 testing centre and has personally encountered people who have tested positive for the virus after they received both the first and second doses of the vaccine. They’ve tended to have no symptoms, or very mild symptoms. “But the question is, are they going to be at risk to pass that on to the next person?” Dr. Khatib asks, with the implication that transmission after vaccination is possible. (28:25)   

How long are we protected against COVID-19 after being fully vaccinated? Dr. Abrams says that researchers don’t actually know how long the immunity lasts yet. “The results so far based on studies are encouraging,” says Dr. Abrams, “that there is protection of at least several months.” Which raises the question: Are we going to need booster shots to maintain immunity against COVID-19 at some point in the months or years after we’ve been fully vaccinated? Dr. Khatib believes the likelihood is high. The COVID booster could even be an annual thing, like the flu shot. (29:20)

LINKS

Referenced in this episode is this CMAJ article about rapid antigen testing by Dr. Isaac Bogoch and others, which argues for the mass deployment of the point-of-care tests as a public health strategy to minimize COVID outbreak risk.

Here’s information about Medcan’s rapid antigen testing service. 

A news report about the outbreak in the Amazon warehouse mentioned in the episode.

Additive to the rapid antigen testing content in this episode is Joshua Gans’ essay, “What does vaccination mean for rapid screening?”

The Takeaway is the YouTube video series that features Medcan docs providing guidance on trending medical topics. This one provides Dr. Nord’s advice on the AstraZeneca vaccine, and whether to get it. Link.

What Can I Do After My First Dose? and Other COVID-19 Questions Answered final web transcript

Christopher Shulgan: Hi, Chris Shulgan here. I'm part of the team that produces Eat Move Think, and one of the frustrating aspects of the pandemic is how difficult it's been to find reliable guidance. Case rate, mortality numbers, ICU admissions—most of us can rattle off the latest figures, but it's difficult to trust an expert to tell us what they all mean. Living through this provokes questions all the time. Like, you look forward for months to getting your first jab, but then once you get it, how does that actually change anything? Everyone has an opinion, and it's difficult to know where to turn.

Christopher Shulgan: What's lucky about producing a show like this is that we actually have access to the experts. For its corporate clients, Medcan provides something called Medical Advisory Services, which is a brain trust of MDs who advise the country's largest corporations about all sorts of pandemic-related issues. So at a moment like this, when we all could use some guidance, we thought it would be great to gather them together, to hear the MDs respond to the questions we've been wondering.

Christopher Shulgan: By way of introduction, Dr. Aisha Khatib is Medcan's clinical director of travel medicine. Dr. Jason Abrams is associate medical director. Dr. Matthew Burnstein has served as director of occupational health and wellness for everyone from the Province of Nova Scotia to Canada Post's Atlantic Division. Dr. Alain Sotto is the occupational medical consultant for the Toronto Transit Commission, in addition to his responsibilities with Medcan. The host for today's episode is Dr. Peter Nord, Medcan's chief medical officer. Let's get to it.

Peter Nord: I'm Dr. Peter Nord. I'm the Chief Medical Officer and the team lead for the Medical Advisory Services team that we have at Medcan. And joining me today, we have Dr. Aisha Khatib, Dr. Jason Abrams, Dr. Al Sotto and Dr. Matthew Burnstein, all physicians that make up the Medical Advisory Services team.

Peter Nord: Well, we're in the midst of a dramatic increase in COVID cases in Canada, due to the B-117 variant. ICUs are maxing out, but thankfully death rates remain low. What makes this third wave different, and can you even vision a fourth wave? Let's start with Dr. Burnstein.

Matthew Burnstein: What makes this third wave different is the variants of concern. The first two waves, we were dealing primarily with the COVID Classic, if one might. In the third wave, we're now dealing with these much more aggressive variants of concern—the UK variant, the Brazilian variant, the South African variants, and a half dozen other minor variants, which are far more aggressive, more easily transmitted, cause more severe disease. So it's a very different bug that we're dealing with.

Matthew Burnstein: Also different is that we've had an opportunity to vaccinate some of the most vulnerable populations, people particularly in long-term care facilities. So the cases have shifted to frontline workers, essential workers. So we're seeing a much younger population who, unfortunately, because they're facing a more aggressive variant, are becoming more ill and ending up in hospitals and ICUs.

Peter Nord: Yeah, so if we're seeing these variants, is that that process that's going to continue? Have we seen this—it's been going on for some time, and we expect it to continue? And maybe Dr. Khatib, you can respond to that with, you know, in thinking about, is there a fourth or a fifth wave? Or is this going to become a permanent thing and endemic with our population?

Aisha Khatib: Thank you, Dr. Nord. So as long as we have continued transmission in the community, there's risk of more variants emerging, and potentially more deadly variants and variants that may mutate enough to evade or escape the immune response that's created either by natural immunity or by the vaccines that have been developed.

Aisha Khatib: So the risk is there. And I think one of the things that we're looking at right now, although we're deep in the throes of the third wave now, is that if we don't get a good handle on the public health strategies that we're using to decrease transmission going forward, then potentially there will be a fourth wave and the fifth wave, once we start opening up—especially prematurely—if we don't have enough of the population vaccinated, or if we have, like, an unequal or inequitable distribution of vaccination. So we really need to be cautious about how we open up, how fast we open up, how many people have been vaccinated.

Aisha Khatib: And also, you know, to be cautious about the fact that the vaccines, with one, just one on board, people need to be cautious that they're not going to be fully immune yet, right? And the other thing is one of the things that we don't know is about the transmission risk when you're vaccinated. So we really still need to maintain those public health measures to help decrease the risk of entering into a bigger fourth wave or fifth wave down the road.

Peter Nord: Yeah, I think that's a big takeaway, the whole aspect that there is no vaccine that is 100 percent effective, so there's always going to be that question mark. And then we just don't know right now around transmission. I think we're assuming that there is a reduced transmission with vaccination, but we don't know that for sure. But one thing for sure, is it's probably not 100 percent reduction in transmission. And so we're going to have to be dealing with these public health measures for some time. I think that's one of the takeaways that we've been talking about now for the last few weeks. And unfortunately, you know, what we're seeing right now—in Ontario, especially—our ICUs again are maxing out. Dr. Sotto, when does the vaccine distribution start to actually tamp down these ICU admissions?

Alain Sotto: Well, Peter, I agree with all the other speakers and their comments. I just wanted to just sort of rephrase it if I could, in the simple four Vs of this pandemic. You know, the variants of concern is the first V, the race for vaccine deployment, and then verification of testing for variants of concern. And then the final V, that is probably the most important and the rate-limiting step in how we operate as far as the society and lockdowns is the ventilators and the lack thereof. Not lack of ventilators per se—I should qualify that—lack of ventilator staff, qualified staff to operate the ventilators. There's not that many people that are trained to operate ventilators. And we have enough ventilators, we just don't have the people to operate them.

Alain Sotto: And what I see is, once we get the vaccine deployed to the majority of the population, we will be able to sort of, you know, race against the variants of concern, as Dr. Khatib has mentioned. And in fact, if you look at the case fatality ratio for the P1 that's been reported in the literature, the case fatality ratio, in 20 to 29 year olds has tripled from 0.04 to 0.13, and that is very disturbing. That's why you see P1 variants admitted to ICUs and dying frequently in Brazilian ICUs. So I think that's where we're heading. And, you know, this is not a good position for us to be in, especially in Canada. So I'm not sure if I answered your question directly, Dr. Nord, but indirectly.

Peter Nord: Yeah. No, I think directly. And on the P1, obviously, we've got some real concerns on the west coast in BC with the development of the P1 variant, and obviously real concerns because of the slightly increased. It appears more severity, more mortality associated with that. You know, thankfully, our vaccines appear to be covering the B-117 quite well. However, as we've said, these new variants in the future may fall outside the bandwidth of the effectiveness of vaccines. And so we'll be constantly developing new vaccines to try and get ahead of the race. The race will not be over soon, it'll be an ongoing race to chase down these variants. And maybe speaking about vaccines, and another v word, the VIPIT, or these blood clots that we've been hearing about with the AstraZeneca vaccine. We've been talking about that a lot over the last couple of weeks. But one thing, Dr. Abrams, that we haven't really explored, do you think that the concerns around VIPIT will actually turn out to be overblown? I mean, these are rare events. We knew they were rare events before COVID. We were having blood clots, the venous circulation and the cerebral circulation. We'd known that it occurred previously. But do you think this is going to be just the concern of the week? Or is it something that's going to have legs to it?

Jason Abrams: Thank you, Dr. Nord, that's a great question. Now when you take a deeper dive into VIPIT right now, what you can see is that it's actually a relatively very rare phenomenon. And the interesting thing is, is that, there's less chance of blood clotting due to the vaccine than there is due to COVID itself. So much like the risk-benefit analysis of taking a COVID vaccine, you weigh the risks and the benefits of taking the vaccine versus the risks and the benefits of getting the illness itself.

Jason Abrams: Interestingly enough, comparisons to other activities that can lead to blood clotting, like taking the oral contraceptive pill, or smoking, for example, the AstraZeneca vaccine in research studies today has been found to cause clotting issues at a lower rate, significantly lower than those two activities themselves.

Peter Nord: That's a great way to frame the risk, because the headlines have got a lot of people concerned about this very rare condition. And frankly, a lot of people are not getting the AstraZeneca. They are waiting. And there's obviously a risk associated with that as well. You know, we've talked from the Medical Advisory Services Team about the three pillars of killing a pandemic, and that's getting the vaccinations out to everybody, rapid testing, and continuing with the public health guidelines, the measures, the distancing, mask wearing, hand hygiene. And we've said it really takes all three of those to work.

Peter Nord: We've talked a little bit about the vaccines, we've mentioned continuing with the long-term application of guidelines. Maybe we can just turn to rapid antigen testing. And again, rapid antigen testing, as opposed to the nasal swabs that we were doing before that initially took many days, we really need to get these effective, inexpensive, rapid turnaround antigen testing tests out into the marketplace. And we're starting to see that now. And in fact, Medcan's participated in pilot projects that have seen us deploying nurses in various settings for this rapid antigen testing. What do you think the future is of rapid antigen testing? Is there a scenario that sees so many people vaccinated that rapid antigen testing becomes unnecessary? And maybe Dr. Sotto, you can start with this one because of the work at the Toronto Transit Commission.

Alain Sotto: Sure, Peter. I think rapid testing, antigen testing is here to stay for the next foreseeable future. Having used it in the workplace directly in a unionized environment, I can tell you it was very well received. And we used it in a targeted approach. So we had an area where there was a lot of employees who came in, perhaps unwittingly, didn't know they were incubating the virus. And we used the rapid antigen test to screen those folks and make sure that once they got the screen test, if they were positive, then we would send them on for a confirmatory PCR tests or molecular test to confirm the diagnosis. But we wouldn't allow them in if the rapid antigen test was positive. So I think rapid antigen tests as it's being used in airports and in other organizations that are, say, critical infrastructure, I think is a really important advent, as you say, in the three pillars, you know, the vaccine, the rapid testing and PPE hygiene. I think the rapid antigen test is one of the mainstays for preventing workplaces from becoming, you know, an outbreak, if you will, which is—an outbreak is defined as two or more cases.

Alain Sotto: And I can also tell you that the questions I had to field before we got the rapid antigen test was, "If I've been vaccinated, will I test positive on the rapid antigen test?" And the answer is clearly no, because the rapid antigen test picks up folks that are infected two days prior to showing symptoms, and up to five days within symptoms. So there's no way that a person who has had the vaccine is going to test positive, unless—one caveat—they become infected unwittingly. And that's the true benefit of rapid antigen tests. So that's here to stay, I believe.

Peter Nord: Yeah, I think we're starting to get those questions. Dr. Burnstein, I'm sure you're getting some of the questions from your clients as well. One of those questions very specifically is, once all of our teams are vaccinated, do we have to bother with rapid antigen testing? And I guess the second piece is, do we have to be wearing masks in the workplace and distancing? What do you say to that?

Matthew Burnstein: At this point in time, we don't have enough information to say that people who are fully vaccinated cannot contract COVID and cannot spread it. And we will have this data over the next few months, which gives Canada lots of time to get two vaccines into everybody's arms. So as was alluded to earlier, we'll all know more in two weeks or four weeks. We're constantly learning about this. At this point in time, I think simply getting two vaccines and two weeks will not be enough for us to let our guard down in the workplace.

Matthew Burnstein: It may be in our home situations, but in the workplace—where we have an obligation under the Occupational Health and Safety Act to protect our workers—I think we're going to continue with masks, social distancing, and testing until we know more. And I did want to add one unique area where rapid testing is particularly useful, and that's in communal living or work settings. I look after a couple of remote mining sites and construction sites, and testing people before they travel to the site, the day of travel, and every three days for the next 10 days has proven to be very effective. We may miss somebody on the first test before they travel, but we'll catch them two or three days later, before they've had a chance to spread it. And also testing people before they leave and go back to their home communities—many of which are remote First Nations, Innu or Inuit communities, where the introduction of a variant or even standard COVID would be incredibly disruptive.

Peter Nord: One of the things we've been hearing here in Ontario is the one particular incident which happened at an Amazon distribution centre. Dr. Khatib, I mean, there was 600 cases linked to this particular distribution centre, so essentially, a super-spreader event. And we've seen this, whether it was at a meatpacking plant or manufacturing facilities. What lessons does this provide for employers in terms of managing large manufacturing facilities, or any real large employee-based facility?

Aisha Khatib: One of the things that's important, especially in these settings where you have, you know, large amounts of people working in factories and workplaces, is the idea of rapid antigen testing used as screening, right? And the reason for that is the fact that Dr. Sotto mentioned, is that you can really pick up pre-symptomatic and posi-symptomatic people before they start showing symptoms, although they may be transmitting the virus to others, and forwarding.

Aisha Khatib: So when we do the testing for PCR, for example, we're already seeing symptomatic people, and we're already potentially a little bit behind the game in contact tracing, and being able to control the spread of the virus. If you're using rapid antigen testing for screening, you have better control and better able to contact trace, to isolate a decrease that spread forward of the virus. And this situation, for example, in the Amazon factory, if everybody had been screening, even if the sensitivity and specificity of that antigen test isn't the greatest, it's still going to pick up enough people to be able to get those people tested, get them isolated, to decrease the risk of transmission in these big super-spreader events.

Aisha Khatib: And I think the other place to look at is things like school, right? School and other large gatherings, other workplaces. I think this is going to be a game changer for these. There's a great article that just came out in CMAJ by Dr. Schwartz, Dr. McGeer and Dr. Bogoch talking about rapid antigen screening being used to decrease the transmission risk going forward.

Alain Sotto: Just to add to that, Dr. Nord, if I could. The rapid antigen test that we used on site was the Panbio rapid antigen test that gets the result in 15 minutes. It's made by Abbott Labs, and it has a 91.4 percent sensitivity rate. So it's actually pretty good for ruling in the disease if you have it, and if you're a possible spreader. So that's what we use. Very well received by unions, which, you know, is always a rate-limiting step. So I have no reservation in recommending it or endorsing it.

Peter Nord: Yeah, so just back to what Dr. Khatib mentioned, CMAJ is the Canadian Medical Association Journal just for everyone as a footnote. And also, both of you have mentioned the sensitivity and specificity. Dr. Abrams, maybe just 30 seconds for people on what that is. Because people have heard, you know, a test has a sensitivity or a specificity. What does that really mean?

Jason Abrams: Yeah, so when we describe sensitivity and specificity, when we discuss sensitivity, we're discussing the ability of a test to rule out the disease. And when we talk about specificity, we're talking about the ability of a test to rule in the presence of the disease. Now these are important when we think of terms like "false positives" and "false negatives," because not every not any test essentially is 100 percent accurate at predicting the presence or absence of the illness that it's testing for. And so the higher the sensitivity and the higher the specificity of the test, the more accurate or reliable the test result becomes.

Peter Nord: So with Canada maximizing first dose distribution, and the second dose stretching on four months later, a huge number of people have questions about how and whether getting the first dose actually changes their lives. You know, can I see my grandkids after my first dose? How long does it take for the effects of the first dose to develop? And even first dose numbers? How much does getting the first dose affect my risk of death from COVID? So why don't we just start with the first one. In terms of that first dose, and some of the statistics, some of what the studies have shown and what they haven't shown. And maybe we can just talk about the effectiveness of the first dose. And we'll maybe start with Dr. Sotto on this one.

Alain Sotto: Sure. That comes up in many webinars that I've been giving as far as the first dose effectiveness, primarily through the mRNA vaccines, namely Pfizer and Moderna. If you look at the graphs on the original studies that were shown, for those that received the placebo versus the vaccine, the 112 days—which is four months—the vaccine effectiveness during the study was not any different from two weeks, to 112 days, which is 16 weeks or four months. So that's why the National Advisory Committee on Immunization—NACI—has said, in lieu of the fact that we don't have enough vaccines to go around, better to give—race towards giving one dose and protecting everybody for at least 80 percent protection for getting the disease, and then vaccinating everyone. So I think if you look at the curve, it speaks for itself. But if I'm describing it, the curve, basically at two weeks after dose one, you're protected all the way up to 112 days. So I think if you look at the science, and the science has been dictating what we do for vaccines, is that you're protected 80 percent. Does that mean you can let your guard down? Absolutely not. The comfort zone is that with 80 percent, that's better than most vaccines in other disease states that we give. So for instance, influenza, we get about 60 to 70 percent efficacy after one dose each year.

Alain Sotto: So I'm good with 80 percent. And we know that in the real-world experience such as the Israeli experience, which about 90 percent of the population has had at least their first dose, they've had a 93 percent reduction in COVID cases. So I think the real-world experience, which is the effectiveness, and then vaccine efficacy in the study of 80 percent after one dose, I think is very telling and comforting.

Peter Nord: So maybe we just need to clarify slightly. When we talk about efficacy of the vaccines being, let's say, 80 percent, that's for the symptoms. So if you have any symptoms at all, you automatically fall into the positive category. So if you had fever for a day, or felt fatigue, in the study population, you would check a box and say, "Yes, I had some symptoms, so I'm falling into the 20 percent." That's the positive. So 80 percent of people had literally no symptoms. What we did know for sure, coming out of those studies, is that 100 percent of the people that were vaccinated, did not end up in hospital and did not die. And that's a massive takeaway. Now what we are seeing in the real world population, so not within the confines of a random, randomized, double-blind, controlled study, is that they're still being highly effective. We are seeing some hospitalizations, probably due to the effect of some of the newer variants, but even in a real-world population, we're seeing way more than 85 percent of people not ending up in hospital after even a single dose of the vaccine. So really positive news, extraordinary in terms of the medical marvel of this century really, to get these kinds of numbers, not just in a study, and not just hospitalizations, but even preventing mild symptoms in people even in a real-world environment. It's a massive takeaway.

Peter Nord: So Dr. Burnstein, what do we say to our listeners that have had their shot? Let's just say they've had their first dose and they want to see their grandkids? What do we say to those people?

Matthew Burnstein: Unfortunately, it doesn't change your behaviour with one dose alone. As Dr. Sotto alluded to, internally, I'm much more comfortable having had my one shot. Externally, my behaviour is exactly the same. And unfortunately, it has to remain that way.

Peter Nord: For sure.

Matthew Burnstein: But it's the start, it's the beginning of the end. We can see the future. I mean, we've got a terrible wave ahead of us. We're not through, we're still climbing in this wave. April and May are going to be rough. But there is a light at the end of the tunnel. It's like we've landed in Normandy, we now just have to fight our way across France. But at least we're on the shore, we can see the end.

Alain Sotto: Right. And furthermore to that, Dr. Burnstein, totally agree. The Public Health Agency of Canada has not issued guidance in fully-vaccinated individuals as of yet. And I want to define what fully-vaccinated individuals are: two doses of a vaccine at least two weeks after your second dose. Once we get the public health agency guidance, then we can move forward and decide what is our less-riskiest step going forward.

Matthew Burnstein: And Dr. Burnstein here again. I might add, one of the biggest mistakes I think Canada has made from the very start is not learning from other countries. We've always been sort of two to four weeks behind Europe. And I think we need to look at Chile as a cautionary tale, because they did a great job rolling out the vaccines, they've got about 33-40 percent of the population vaccinated, and yet their numbers are going through the roof because they let their guard down prematurely. And had we been paying attention to what was happening in Europe, we may have avoided the third wave that we're in now.

Peter Nord: So that goes to another common question, so maybe for Dr. Khatib. So after you've had, let's just say our first dose, and we know the first dose is doing a relatively good job. Second dose is great to get us to the final numbers. But during that time, what's the risk that we're actually going to be passing COVID on to someone else? And that kind of goes to Dr. Burnstein's example in Chile.

Aisha Khatib: Yes, Dr. Nord. So we actually don't know the exact numbers right now. So there are some early studies coming out showing that the transmission risk after you've been fully vaccinated does decrease, and it can be anywhere between 30 to 60 percent. But at the moment—especially with the variants that we're seeing, and some of the decreased efficacy against the vaccine that we're seeing with the variants, we still potentially have the risk of transmitting or carrying the virus and transmitting it to others. So the difference is like, for example, with the flu vaccine. When you get the flu vaccine, one of the reasons that you get the flu vaccine is so you decrease that risk of transmitting it to somebody else. It stops that transmission of the virus. In the studies that were done for these vaccines, they looked at efficacy against severity, against hospitalization and death, right? And all the vaccines across the board are 100 percent effective at doing so.

Aisha Khatib: The studies didn't look at the transmission of virus after you've been vaccinated. And that's something that's being examined right now. And as Dr. Burnstein mentioned, those studies will probably be coming out in the next few months. But at the moment, that risk is potentially still there, and so we still need to be cautious. And like I said, I have seen people who have tested positive after they've received two vaccines. I've seen people who've tested positive after they've received one vaccine. Some of them have had no symptoms, so that's reassuring. Or very mild symptoms, that's reassuring. But they were exposed from somebody who was symptomatic in their family or their workplace. And so they still got that virus, even though they were vaccinated. And yes, they're protected, they're not having those symptoms, but the question is, are they going to be at risk to pass that on to the next person? And that's the issue right now.

Peter Nord: And so maybe we can wrap up with another common question that we get, Dr. Abrams, around the duration of protection from the vaccination. So we've got our first dose, maybe we've even got our second dose. How long are we protected from catching COVID ourselves?

Jason Abrams: Yeah. Unfortunately, that's another unknown answer, if we want to be precise at this time. The results so far based on studies is encouraging, that there is an extended response of at least several months. The problem is because this is a new virus and the vaccines are new, we actually don't know how long people are protected for, whether they've had the infection previously, or they've had vaccination, be it a partial series or a full series of vaccination. And part of that maybe because of all these variants that are coming up. Maybe in the future, we'll need to revaccinate to address a new variant of COVID virus in the future.

Peter Nord: I'll put a plug in for Medcan that we're actually doing a research study to look at how long the antibody, at least part of the immune system, the IgG is lasting for individuals that we're testing that come back positive from their antibody test. Because it's a common question: how long, and are we looking at an every-six-months or annual COVID shot? So do we have our influenza A, B and C—being COVID—on an annual basis? What does the future look like?

Aisha Khatib: Yeah. Well, we know from natural immunity from COVID, that people have been showing to produce antibodies, which basically give you that immunity against the virus, anywhere between three to eight months. What we don't know is what level of antibody you really need to maintain. The boosters that Dr. Abrams mentions about is that, in regards to if there are variants that develop, that we may need immunity against. But I agree with you, Dr. Nord. I think that we probably will be looking at booster shots. And I know there's studies being done for that right now, like, looking at people getting their third shot. But remember the theory of vaccines as well is that the vaccines really work in decreasing symptomatic people as well, right?

Aisha Khatib: So the more people we get vaccinated, the less people that are going to be as symptomatic, they're going to be shedding less virus, they're going to be transmitting that virus less, they're going to be infecting less people. And so we also should see those numbers go down. But then you're going to also have that herd immunity that we talk about, with those level of vaccines, of those people being vaccinated as Dr. Sotto mentioned. So it is promising, and I think it's one of the things that we're going to be watching to see what happens.

Peter Nord: And that's probably a great place to stop in terms of a positive upswing. There's certainly some challenges we've had to face. We've talked about some really tough measures that we've had to endure and we're going to continue to have to endure, but the future does look bright. We have optimism with the vaccines and the duration of protection from the vaccines. So thank you all so much for this time. This is—as always, this is the brain trust of the Medical Advisory Services Team that we could tap into today. So on behalf of all of our listeners, great episode, thanks for all your insights and your wisdom and your time today.

Alain Sotto: Thank you.

Aisha Khatib: Thank you. Thanks for listening, everyone.

Christopher Shulgan: That was Medcan's Medical Advisory Services Team talking about pandemic and related issues in an episode hosted by chief medical officer, Dr. Peter Nord. Also featured were Dr. Aisha Khatib, Dr. Jason Abrams, Dr. Matthew Burnstein and Dr. Alain Sotto.

Christopher Shulgan: I'm executive producer Christopher Shulgan. Find show notes, links and full episode transcripts at EatMoveThinkpodcast.com.

Christopher Shulgan: Eat Move Think is produced by Ghost Bureau. Senior producer is Russell Gragg. Social and production support from Chantel Guertin and Emily Mannella.

Christopher Shulgan: Remember to rate and subscribe to Eat Move Think on your favourite podcast platform, and follow our host Shaun Francis on Twitter and Instagram @Shauncfrancis—that's Shaun with a U—and Medcan @medcanlivewell. We'll be back soon with a new episode examining the latest in health and wellness.