Ep. 6: Elizabeth Carlton, PhD, MPH, Assistant Professor, Colorado School of Public Health. Topic: COVID-19 and Public Health
Kathy: Hello, and welcome to Episode 6 of the Smarter Healthcare Podcast. I hope all of you are well and safe during these challenging times. Today, we will be speaking about the COVID-19 pandemic through the lens of a public health researcher. Our guest is Elizabeth Carlton, assistant professor in the Department of Environmental and Occupational Health at the Colorado School of Public Health. Beth is part of a team of scientists working to understand the trajectory of COVID-19 in Colorado and the potential impacts of transmission control strategies. She shares with us some of the latest around the pandemic and guidance for how we can think about spending time with others this summer. Here’s our conversation.
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Kathy: Hi Beth, and welcome to the podcast.
Beth: Hi Kathy, thanks for having me.
Kathy: Yeah, now I feel like my listeners should know at the very outset that you are one of my oldest and dearest friends, we’ve known each other since we were three years old.
Beth: I was two-and-a-half and I met you at your turning three-year-old birthday party. Your family graciously invited the new neighbors over for which I’m very grateful.
Kathy: But now we’re older, wiser, and I am very happy to know such a smart person who is going to educate us today on the COVID-19 pandemic. So Beth, if you could start off by telling us a little bit about your current role and what you’re focusing on during the pandemic.
Beth: I’m an environmental epidemiologist that studies infectious diseases. So I think about how infectious diseases move from one person to another, and I often study more complicated diseases like water-borne diseases that spend a lot of time between hosts. I’ve always been interested in how infectious diseases emerge, and how they go away. And when COVID-19 showed up, it felt in some ways like this elaborate oral exam for my doctoral studies many years ago that I created for myself. So what I’ve been doing the past few months is working with a team of bio-statisticians, infectious disease modelers, an epidemiologist, and health policy people, to really think about how the disease is being transmitted, and specifically in Colorado, understanding what’s happened to date, and what might happen in the future. So we’ve been working really closely with the state of Colorado to try to project what we expect to happen in the near term and trying to estimate the impact of different types of interventions that might happen. Everything from mask wearing to encouraging people to stay home.
Kathy: Now did public health experts expect that a pandemic like this would ever impact the globe to the extent that it has?
Beth: Ooh, that’s a great question. There has always been concern about the potential for a disease like this to emerge. And we have seen diseases emerge at growing rates for decades. One of the big emerging infectious diseases that many of us are familiar with is HIV/AIDS, which emerged in the 1980s and has led to millions and millions of deaths. Most infectious diseases, when they emerge, emerge and quietly go away. The big concern in recent years has been about flu, and pandemic flu and its ability to really cause mass illness and fatalities, and so I think what is different about what’s happening now is that although it is a respiratory infection, it’s not influenza, it’s coronavirus, which behaves a little bit differently. So I think there are people out there who would say yes, we thought something like this could happen, and we’ve been advocating to be prepared for many years, but I think nobody could quite anticipate what this infectious disease was going to look like. And how it would present in its current form.
Kathy: Now most states have started reopening, so far they are in various stages of reopening. From a public health perspective, how is that going right now?
Beth: Yeah, that’s a good question. I think this pandemic has been so challenging because on one hand you have the potential for the virus to cause massive loss of life, and on the other you have the potential for the control measures we’re using to cause huge financial and mental health consequences, and so on our team we’ve been saying it feels like there’s no margin for error, right? We want to get the estimates right because we feel like if we underestimate the potential health impacts there could be mass casualties, if we overestimate the potential health impacts there could be unnecessary financial or mental health burdens. And I think the state’s transition to this next phase of the epidemic has really been motivated by a desire to restore some of the economic activity that is so crucial to our economy and quite frankly our well-being. We know that income is one of the strongest determinants of health. That said, I think states are moving towards reopening in a lot of different ways, and I think the things that are least worrisome are activities that don’t require a lot of contact between people, right? We know this disease thrives on people being close together. So for example opening curbside retail is not – opening restaurants for delivery and takeout or curbside retail is probably a low-risk scenario. Reopening huge gatherings of people together in an enclosed space is really worrying. In Colorado we’ve been watching the numbers really closely, and we think we have about a 13-day lag between when we see – we track hospitalizations – when we see hospitalizations happening and when people are getting infected. So for example, if a person gets infected and needs to go to the hospital, it will take them on average about 13 days to have to show up at the hospital. So what we’re seeing now in Colorado really reflects policies two weeks prior, or earlier than that. And so it’s this nerve-wracking wait and see, where everyone is closely following the numbers and really hoping they don’t increase, and in Colorado the numbers have been going down continually, but we’re starting to see that the declines are slowing and so, the concern obviously is that there’s a potential if reopening is not done methodically for cases to increase in the future. And I think - that’s very scary to a lot of people.
Kathy: Are there any concerning trends in some of the recent data that you’ve looked at?
Beth: In Colorado we’ve seen the rate of decline start to slow, and I’m sorry, I’ll speak to Colorado, but I feel like it’s a – I understand those data most of all and I also feel like it’s a nice example of what might happen elsewhere. We reopened as a state – or transitioned from stay-at-home to safer at home on April 26th, but actually half of Colorado lives in the Denver metro region, and they were under stay-at-home orders through May 8th. So they had an extra couple of weeks. And what we’re seeing is right after May 8th the decline has started to slow down. And reopening in most places has not been this switch that gets turned on from completely closed to completely back to our pre-COVID time. Instead it’s kind of this slow rolling out of different, allowing different activities to resume with cautions in place. And so I think what I see that is encouraging is that there is growing guidance for different sectors about how to resume some of our old lives in ways that can protect against COVID transmission. I think what could be worrying is in places where people think they can just go back to pre-COVID days and as much as we all desperately miss the kind of carefree time before this disease emerged, I think in the near-term we are going to all have to have precautions in place to try to reduce the threat of transmission. So reopening doesn’t mean back to normal. It means finding this new normal moving forward, because I think we’re in this for the long haul.
Kathy: Right. Now over the next several weeks, I know that you talked about that 13-day lag between when a person contracts COVID and when they typically need to go to the hospital. Are there other things that we should look for over the next several weeks?
Beth: Yeah, one of the big priorities has been to ramp up testing capacity around the U.S. And so you may see, as states increase their testing capacity that the number of positive cases increases just because they’re detecting a greater proportion of those infectious individuals, but what we do want to see is that the number of tests is going up, and the tests per capita is going up. So if you look at the total number of positives, that may be increasing, but the proportion of tests that are positive should hopefully be going down as we reach out and get more people. And the reason why testing is so important is because the more we can identify people who are positive, and encourage them to stay home and prevent spreading the infection, the better we can control this infection. So that’s one of the big indicators. There has been this really interesting use of mobility data to try to get at how people are moving around and how that’s changing over time. This is everything from using Department of Transportation data, just looking at people going through different monitored points for car counts, to using aggregated cellphone data to look at pings. And I think that’s a really interesting application of kind of this new big data of how to look at how populations are moving. It might help us understand how populations may be moving from one area that potentially has a concentration of infections – a hot spot – to areas that don’t, and have the potential to spread. I think that that big unanswered question there is how well does cellphone mobility or traffic mobility really map to transmit the disease? Because we all know we could get in our car – I could go and drive to Massachusetts right now if I could just Cannonball Run it and not contribute to any transmissions, I could just stay in my car, right? It’s really about people interacting with other people in close proximity that seems to really matter. So I think the mobility data is going to be monitored very closely with this big asterisk that we don’t fully understand how well that maps to transmission. And then the other data to look at is obviously mortality. How many people are dying? And that’s one of the most sensitive measures along with hospitalizations, although is becoming increasingly complicated because of how different areas are reporting mortality. Some are reporting only direct COVID deaths, some are reporting anyone who tests positive as COVID as deaths. From an epidemiologist perspective, I don’t – I’m less worried about how they do it, just that it’s all done consistently so we can look at the numbers consistently over time. If the definitions are changing over time it’s going to change the patterns of the data.
Kathy: Now you had just talked about some of this mobility and people should avoid congregating…we’re just about to hit summer, which is a time when everyone typically gets together. What should we be thinking about this summer? What are some – what should we plan on this summer for how we spend our time and how we do congregate, if at all?
Beth: Yeah, this is such a great and complicated question, both on a professional and personal level. I am part of this family that loves to spend their summer together, moving in and out of houses, eating lots of long meals together, grandkids, and grandparents, and everyone moving around. What we know about COVID is that it really thrives on people being close together. We know that older populations are much higher risk if they get infected of getting really sick, potentially dying of the disease. So I’ve been using this people, space, time, and place framework, of thinking about any activity in terms of how many people you are potentially going to come in contact with? Space, can you maintain six feet or more distance? Time, how long are you going to be in contact with these people? There’s a big difference between passing somebody in a hallway or on a running path versus sitting down across the table and having a meal with them in terms of how much time. And then Place – are you inside or outside? We know that being outside is less risky than being inside, just because there’s more space for the air and the virus to disperse. And also are you in a place where – that is considered to be a hot spot right now, potentially traveling to there or if you live, if you’re thinking about travel, if you live in a place that has a lot of infections right now, what are your ethical obligations as a good citizen not to travel someplace that doesn’t have very many infections right now. So that’s a long-winded way of saying that it’s hard this summer. I think what seems to be lowest risk as people try to prioritize is – contain travel within your family unit. Like if you want to go camping and can find a way that you’re not going to be jam-packed in the camping bathrooms with everybody then that’s probably a pretty low-risk scenario. Going to a family reunion with 50 people is probably – particularly with grandmas and grandpas around - is probably a pretty high-risk situation, particularly for those older populations. I do feel like there’s this need for clear guidance for people because some people are very cavalier and really feel like they can do anything they want, but many people are really afraid right now, and trying to figure out how to have a life and not live in constant fear of that virus. So I do think it’s worthwhile to think about these easy-win situations, like going hiking with your family. Sorry, I’m going to give these very Colorado examples – we all hike in Colorado. Or having a barbecue or having drinks with friends where you’re sitting outside. I have a colleague who has happy hour with her next-door neighbors and they just sit on their lawns and hang out, and they’re outside and they’re socially distanced – that’s a pretty low-risk scenario. So finding those solutions. Or, also I think that - sorry, I’m probably sticking my neck out a little bit but - I also feel like if somebody’s been living alone for a long time and is socially isolating, and they have other people who have been living alone or that have been social isolating for a long time, it’s probably okay for them to interact in ways that help mental health and help them prioritize the contacts that are most meaningful for them. I was telling my mom the other day it’s like you have a punch card and you only get so many punches per week, so choose your contacts wisely. Do you want to spend those at the grocery store, or do you want to spend those with your friends?
Kathy: I like that.
Beth: I’m not sure my mom liked that one.
Kathy: Now I know that a lot of people, like you said, a lot of people need kind of the clear guidance and I know that a lot of people want to know like, when is this going to be all over. When is the end point? From a public health perspective, what are you looking at for the end point of all of this?
Beth: I think the honest truth is we don’t know. And I feel like that is extremely frustrating – for us, and more so for the general public. What seems clear is that we are in this for the long haul. That the risk of this disease is not going to disappear this summer or next fall. There is some hope that over this summer because people spend more time outside, because school is just not in session, that we won’t see a big spike in infections this summer. There is real fear that next fall and winter we could have another wave, and just to be totally clear, there is fear among many experts, myself included, that if we take all the guardrails off right now, that there will be a spike this summer. I think the big unanswered questions that will help answer your question is what – what is happening in terms of immunity? Once somebody is infected are they immune for life? Or do they have short-term immunity? And how much is any seasonal impact on transmission, like temperature and humidity really impacting things? Because that might help the virus to be less severe this summer but then more severe in the winter. But the short answer is I would anticipate for the next six, at least, months we are going to be dealing with this virus. And I would love to be wrong about that, let me just say, but looking at evidence from other places, like China, they controlled the epidemic in Wuhan, and they do see sporadic cases even now.
Kathy: Now when we look back at all of this in five, ten years, what do you think some of the big learnings will be from this pandemic?
Beth: Well I’ll give the very biased public health response and say, invest in public health. I think the other thing that’s really disturbing about this outbreak is how much it preys on low-income populations and minority populations and populations of color and we’ve seen – and vulnerable populations in our society – people in nursing homes, people in prisons. And so I hope that this epidemic will prompt a real discussion about what is the right way to reform health care so that we can protect all members of our society? What is the right way to invest in public health infrastructure so that we do have a coordinated response from the federal level to the local level? How should we be tracking immunity? I spend my – I love thinking about data and numbers and I spend a lot of time thinking about how to measure things, but as everyone has seen in this epidemic how fraught even what seems like the simplest measures can become, like COVID-19 mortalities, death counts, can we come up with standardized ways to report in these really fluid emerging situations, and capture these data at a large scale. Because I think that has been a really frustrating part of this response. I think we’re going to understand influenza a lot better when this is all over. Because there’s actually a lot of interesting open questions about how other respiratory viruses are transmitted and I feel like what’s been so inspiring over the past few months is how much the scientific workforce has just piled on trying to answer so many questions about COVID-19 that will probably help us understand many other diseases as well.
Kathy: Well thank you Beth, this was a great conversation, thank you so much for joining me.
Beth: Thanks for having me, it’s been a pleasure.
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Kathy: Thank you all for joining us for this episode of the Smarter Healthcare Podcast. I hope you enjoyed our conversation – I know my mom was thrilled I was having Beth as a guest!
If you’d like to keep tabs on Beth’s research or thoughts on the COVID-19 pandemic, you can follow her on Twitter @EJCarltonEOH. You can also follow me on Twitter @ksucich or @smarthcpodcast. Feel free to drop me a line with comments or guest suggestions.
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