What the Numbers Say: How Can We Get to a Safer Summer?
On Friday April 23, Fields invited Dr. Peter Jüni and Dr. Samira Mubareka for a discussion on the latest modelling from the Ontario Science Advisory Table. In the course of the discussion, they shared what they've learned about mutations and variants of concern, why we can't vaccinate ourselves out of this pandemic, and perhaps top of mind for many Canadians, whether they think we'll get to have a summer this year. Below are some of the highlights of our conversation.
Q: Can you give us a quick rundown on where we are right now in terms of the numbers, caseloads, hospital occupancy and ICU occupancy?
Peter Jüni: I’ll start with the good news. In terms of the case numbers, it doesn’t look as if this [third wave is] completely and utterly out of control anymore. What's happened now is the [public safety] measures undertaken about two weeks ago started to kick in, so the curve appears to be flattening. This is still a wobbly story and we're not at all over the hill. What happens now is that hospitalizations will continue to go up for a week, for two weeks until they’ll flatten at the very high level [in terms of] ICU admissions, intensive care, and admissions. And then occupancy will continue to go up for at least three weeks.
So, the next three weeks of growth in ICU occupancy is just baked in. This, makes it extremely important now that we not only flatten the curve, but also get these case numbers down. They need to plummet. That means we need to take more [public safety] measures and all of us need to help in any way we can. My impression over the last week or so is that there has been a shift in the province, which I'm extremely grateful for: there's so much solidarity going on among people in the province. If we continue to do the right thing, we will get the bugger under control.
Q: Just to clarify: You said there's a time lag between when a public health measure is introduced and when we see the effect of those measures in terms of cases in the hospital or in the ICU, is that correct?
PJ: Yes. This is one of the challenges around what makes it so difficult for many people to understand the numbers. What we're doing here is like driving a self-accelerating car. If you don't step on the brake, it will continue to accelerate more and more and more until you crash into a wall. But if you do start to step on the brake, you won't see anything for at least 10-12 days when it comes to case numbers. What is much more concerning is that you won't see any [progress] after that for another two to three weeks when it comes to ICU, admissions and occupancy: the numbers will just continue to go up.
This is one of the reasons that politicians across the world also struggle so much. [The concept of] exponential growth may be very straightforward for people like you or me, but it's very difficult to understand. And now with the third wave [we are experiencing] fatigue and the challenges we have now [are] that the measures that worked before relatively well… won't work that well anymore because these new variants are about 50% more transmissible. Meaning if we did something before and the cases started to plummet, it won't happen that way anymore and cases will still go up. So, we have to do better than before even though we're also tired.
Q: We've also been tracking the acceleration of the virus; in other words, how quickly the growth has been increasing. And right now [in Ontario], we are in a phase of deceleration, meaning the growth rate is going down. That's another piece of good news. Samira, I know that Sunnybrook [Hospital in Toronto] has set up a field hospital to deal with the overflow in the ICU. ICUs are stretched beyond capacity, and this must be a huge challenge for frontline workers. Can you tell us a little bit about the numbers there and the challenges you're dealing with in real time?
Samira Mubareka: I have to say this, this third wave has made the second wave feel like a walk in the park. I never would have said that back in December, but this is unprecedented. Our numbers have looked similar to what Peter has already described. We had a rapid ascent, this idea of an accelerating vehicle. There was certainly a sense of momentum, which was out of control with a little bit of a plateau. In the last 24 to 48, maybe 72 hours things have sort of calmed down a little bit, but we know from previous experience they could also go back up. You're correct in that we do have a field hospital and this really underscores the importance of emergency preparedness. It feels a little bit better knowing it's there if needed and it was preparing to accept patients this week.
The idea for the field hospital really is more for recovered patients. So hopefully the most stable COVID patients will be there, while the really acutely unwell and critically unwell will be managed on the hospital side. In terms of the challenges, there are a number. Obviously, logistics is one; we’ve never done this before, and I've been absolutely blown away and impressed by how this has come together in a fairly short amount of time.
But I've heard other people say a bed is just a bed. There's so much more that needs to come with a bed. You can have a lovely mobile health unit, but unless you have staffing for it and expertise and all the support as well - some of the details around how are we going to get X-rays done? How are results going to be phoned back? These may seem like minor details, but when it comes to individual and management are absolutely critical. I think some of the other challenges are around what's happening to the healthcare workforce right now. You've heard a lot about burnout, but I think it's being compounded also by a degree of moral injury in a way: people having to make some pretty tough decisions. And I do worry long-term how this can be sustained. I think it's going to be really important that supports are put in place. I heard earlier today that a number of healthcare workers are likely to leave the field after the pandemic given what's happened and this could have very [damaging] long-term repercussions in terms of our general healthcare delivery.
Q: I wonder if we could talk a little bit about the modelling and predictions for the near future. Peter, there was an interesting slide that [Adelsteinn] Brown had in his presentation last week on some scenarios showing the effect of a stay-at-home order together with increased vaccination. Could you walk us through these numbers and help us understand what is being said?
[Text contracted for length and clarity].
PJ: If we were on the same trajectory as other countries and we would have just tried to vaccinate our way out of the pandemic, we would have experienced a peak of roughly 30,000 cases before slowly going down at the other end of this epidemic curve now. If we continue stay asleep at the wheel where nobody [takes any preventative measures], then that would be happening. This curve flattened [see slide], and then bent downwards is the effect of vaccinating 100,000 doses daily in the province, one dose per person. Many people, including myself, have said we can't vaccinate ourselves out of this third wave. It’s impossible. Viruses don't have legs or wings. They need people. So, if people don't meet inside anymore, we will be able to start to get this curve that you see here under control.
Q: To summarize, our only chance at a semblance of normalcy is really through the third possibility. Is that right?
PJ: Yes. We need to go into the green curve [see slide] and do that for long enough. The better we get, the more we help all of us [and] the better this will all work out. This is one of the challenges we have with our political systems: We're all individualist and our politicians are also accustomed to that. Politicians are not conditioned to be successful with the marshmallow test. This is all about short-term gain and economic considerations that [lead to a late reaction]. And this is an international phenomenon; we are not special in Ontario. And what you get [with this approach] are just compromises where you end up with something that is actually much more painful, and much more economically impactful than if you’d acted strongly and quickly from the outset. Only then are you able to approach [lockdown measures] a bit differently and fully benefit from the vaccines. That's really important: We can't benefit from the vaccines when we're already a mess. Then the force of infection is too large. Remember a vaccine is never 100% effective; even the great vaccines that we have for COVID are only 90% effective. The more cases you have out there, the higher the force of infection. If you want to benefit most from the vaccines, you need to be on the green curve and need to do this long enough, then the vaccine effect kicks in much more beautifully.
Q: There’s a lot we don’t know about the variants and that we are actively investigating. Steven asks in the chat: Given that we don't know very much about the variants, how can we do the modelling?
PJ: What we are now starting to see in different parts of the world is that it doesn't even have to be the same mutation. There are two things that apparently give the [mutations] an evolutionary edge. One thing is, as pointed out by Samira, viruses like to latch easier onto the cells, and for the variants of concern that we’re talking about, all of them have the same type of mutation that they latch more easily onto the cells. This helps us understand why it makes sense when we start to observe that these variants in the UK are about 40% to 50% more transmissible. The second story is that it seems these buggers just try to be subversive with the immune system and two of the variants – the one in Brazil, B.1 and the one originally detected in South Africa – have a mutation in common that basically allows them to subvert the immune system.
SM: We know now that this variant called B.1.617 is in Canada and it sounds like it's now in three provinces at least. We have to be really vigilant. Underestimating this virus is something we do at our own peril. Really early on, people were saying it's a very stable virus; that it doesn't mutate nearly as quickly as flu – and in a way that still might be true. But we now know that viral activity in humans increases the rate of change within the genome. You give this virus an opportunity to adapt and it will. There's no reason why it wouldn't. We were a little bit naive thinking, ‘Oh, it'll stay stable’. As it's circulated more, there are now partially immune individuals that some would say are partly driving these mutations – but I don't know that we know entirely what's driving these mutations. We've had interesting discussions around whether vaccination is going to enhance or reduce selection, because it's going to dampen viral activity to a point where there will be fewer opportunities for transmission, but every opportunity for transmission is also an opportunity for mutation and it can also happen within the host. We'll probably never know the actual origin of this virus, which is a whole other discussion, but there was some discussion that these variants of concern initially emerged from an immunocompromised host potential with prolonged viral replication who may or may not have been treated with convalescent plasma. Who really knows? We can probably test it in animal models about how translatable that is.
Q: Here's a question from Martha. Looking to the summer, it is an observation that the flu and probably COVID will have a lower transmissibility. If that's true, why? And if this is simply because of the effect of temperature and humidity on aerosols, should we avoid air-conditioned, cold, dry environments in the summer?
PJ: I mean, what do we do in the winter? We go inside and, depending on where you live, we congregate. Perhaps that's more important than the actual biophysical properties. We actually tested this in an experimental model to see whether or not the flu transmitted better in Guinea pigs at a range of temperatures and relative humidities. And it did confirm that there is enhanced transmission at low temperatures and low relative humidity. So there certainly is a biophysical component that's not just based on behavior. To answer the question about dry, air-conditioned spaces, I would say what you need are well-ventilated spaces and that's probably more important than the actual temperature and relative humidity. I don't have the nerve to actually aerosolize the virus at a range of temperature and relative humidities, but no doubt those experiments will be forthcoming. To me, it's really the aspect of congregating and poor ventilation. That's going to drive transmission, whether it's in an air-conditioned environment or not.
Q: Susanna asks about people who mask inadequately, such as not covering their nose. As you know, the role of participation in public health measures is very important in this effect. What would you say to the public about this and how might we help people to cooperate?
PJ: Last September, we did a randomized trial of masking in schools with kids. What we actually saw is that kids make much less of a mess with masks than we [adults] do. That’s humbling. We should just stop resisting and do the right thing. And I think it's important to really have a clear messaging – much clearer than the discussions currently going on – how important masks are not only against the droplets. You know, that's the obvious swarm, you know, the searching that is having a mask, you know, the operation theater and the protection is mainly against droplets. You know, when, when it's, when it's there, but medical masks, close masks also partially not completely, but partially also protect you against small particles in the air, as small as the aerosols, but also everything in between. And the point is now, if we were to be better in that, you know, just having two different aspects that we just try to emphasize wellness.
I sound like a broken record in that I said many times during the last two months only some people didn't hear it. It seems outdoors is much better than indoors, but if you're outdoors closer to me to see, would like to wear a mask, why there it's because of the droplets and the aerosols are literally blown away, I would say because of the fresh air, no. And also probably because of the additional best infections through ultraviolet light indoors, you're in trouble. And it doesn't matter whether you're two meters apart or, uh, for me to support it's all about wearing the mask consistently. And we would just need to message that clearly. And I think where we haven't been as many other places really consistent and clear is about the very simple messages about inside versus outside about two meters distance and about the mask. And then, you know, also just really making clear, like with the vaccines, this is not just only about yourself, but it's about everyone and it's a deeply altruistic act, do the right thing.
SM: I'd like to underscore is what Peter said about altruism. Some people understandably consider bending the rules sometimes. Just remember that what might seem like a minor decision in that moment, whether it's to meet up with friends or family, or forgo restrictions around congregation, realize that it could lead to someone's grandparent or now potentially parent or sibling ending up in critical care. Maybe not someone you know directly, but two, three degrees of separation, right? You may never find out. What seemed like very trite, minor decisions on a daily basis could have profound implications for a family weeks later. I would be lying if I said it’s not tempting to do ‘X’ this weekend. They teach this to kids in schools: make the right decision and think it through; it's not just about the immediate. The repercussions are so significant and we have to keep reminding ourselves because we are all getting tired.
PJ: What we all are doing depends on us. Even if you make a misstep tomorrow morning, every single step after that where you try to be as safe as possible contributes in a positive way. That's one of the traps that people fall into. It’s like safe sex. I once didn't use a condom, so I stopped using condoms. No, that's not the point. You slipped once; this doesn't mean you have to slip 10 minutes later. So we're at the point where we all need to understand the severity of the situation we're in. That’s why I keep trying to communicate. And it's very simple: be outside, not inside. Wear a mask if you're closer than two meters [to someone] outside, always wear a mask when you're inside. And it's as simple as that. Don't overthink it.
Q: Finally, what do we need to do to have a summer this year?
PJ: First of all, we need to really be realistic about where we are in this pandemic. Pandemics have a beginning, a middle and an end, and we are very close to the end of this pandemic if we do things wisely. But this means right now. Remember the marshmallow test. If we want to have a real summer, we need to be really strict with the next few weeks and help each other until we have enough people who are vaccinated. I heard somebody say this will be like the Roaring 20s after World War I. Forget it! It won't be the Roaring 20s this summer; this summer needs to be very carefully handled, where we still have quite a lot of restrictions, but it will not be much different, I would hope, than last summer. We cannot be overly excited right now. We will have an acid test in the autumn when it gets cold again and we need to be aware of that. We don't know how this all will play out exactly, but if we want a summer and not being locked on, we now need to get these numbers down right now.
SM: I think it's going to be a summer of slowness, you know, no racing to reopen. It's that delayed gratification. If we want to have the following, we need to constantly remind ourselves of that. We need to just slow down, take stock and plan now as to what we could do over the course of the summer to enable all of this. And one thing we haven't really talked about is where the viral activity has really been: vulnerable populations. What are their summer options? Some people don't have as many summer options. And I think we all individually need to think about how we make it easier for everybody, not just ourselves. We do a lot of navel-gazing. We need to look up, look at the horizon and see how we can help everybody because what we do [individually] will make a difference for everyone in the community.
I think that's a really important point to bring the discussion together at the very end. The world is interconnected. Society is not homogeneous, it's heterogeneous. And if any one section of society is in trouble, they're all in trouble. So, if we're going to learn the lessons of the past, if we're going to conquer this, we're going to have to work together. We're going to have to help each other. I really like the idea of viewing this as an altruistic service to each other, but at the same time, I would agree that it's not a doom and gloom scenario; it's a question of doing the right thing now, and there is a way forward. So we can be cautiously optimistic, alert and vigilant and know that we are part of the game. We have a role to play.