Lori Walsh: COVID-19 cases in North Dakota and South Dakota are rising faster than anywhere in the nation. We worked hard to flatten the curve early in the pandemic as public officials watch larger urban centers struggled to contain the virus. Now we contend with the impact of large summer gatherings, like the Sturgis motorcycle rally, students go back to the classroom. College students have returned to campus, and maybe we're all a little weary from months of worrying and hand washing and watching politics spark fierce debate over efforts to slow the spread. Meanwhile, research scientists have been furiously working, not only to understand the virus, but to eradicate it. And every week we've been bringing you updates on what we know about SARS-CoV2 here on SDPB Radio and In The Moment. Today, we welcome Dr. Susan Hoover. She specializes in infectious disease and travel medicine at Sanford Health. She also serves as an associate professor of internal medicine at the University of South Dakota Sanford School of Medicine. Dr. Hoover, welcome. Thanks for being here today.
Dr. Susan Hoover: Thank you. Glad to be here.
Lori Walsh: I want to talk a little bit about, let's start with vaccines and with immunity because as we move into fall, a lot of this has been muddied by a campaign season and promises that might be politically, convenient but we're not really sure how to separate the science from the politics at some point. So from your point of view, let's put all that politics aside and tell us, how is the search for a vaccine going?
Dr. Susan Hoover: It's going, I would have to say, amazingly fast. We need to remember that this virus was discovered about nine months ago. And so already we know so much about people's response to the infection, the spectrum of illness it can cause, and we have several candidates already being developed as potential vaccines. So I think by the measure of any previous vaccine development effort, one would have to say, this is going very well.
Lori Walsh: It goes well because of the effort that was going into it globally, but also do we have a foundation scientifically for other coronaviruses? How have we been helped by what we already knew?
Dr. Susan Hoover: That's a great question. So as you know, there are four human coronaviruses that have been known for a long time that cause the common cold. And then there are two that cause more serious infections, SARS coronavirus, which caused the SARS type of pneumonia in 2003 and so. And then MERS, which causes an illness called Middle East Respiratory Syndrome, which is still around although it seems to be much less prevalent in the human population. It's not really very contagious from person to person. So we know that people who get colds, as all of our listeners have experienced, can get colds again. So people who get a cold with a particular type of common cold coronavirus do seem to be protected from it for a matter of months to maybe even a couple of years. People who got SARS, fortunately, that virus was kind of exterminated from the human population, thanks to good contact tracing and infection control so we didn't really get a chance to see whether people could be reinfected. And so far infection with MERS would seem to protect against re-infection, but there are so few people that it's hard to say. But I do think we have some experience with coronaviruses. We know that humans can develop immunity to them. So we don't have to start exactly at square one with this new virus.
Lori Walsh: Now were some of these vaccine trials halted for safety recently, and now are back up and running? What can you tell us about some of the safety protocols and what we're learning as we move forward so quickly with the search for a vaccine?
Dr. Susan Hoover: Right. So I know of one, and that was the vaccine that's being developed by AstraZeneca Company in partnership with the University of Oxford. That one is in phase three trials. And as sometimes happens in clinical trials, if there is an unexpected event for safety's sake and out of abundance of caution, they put all new enrollment on hold until they can sort out what was the event and was it plausible that it was related to the vaccine that's being studied. So that happened in the past week or so, and just in the past couple of days, that trial has been restarted. And I want to emphasize that this is not at all unusual in clinical trials and it's actually a good thing. It shows that the system is working and that the checks and balances are in place to keep us from going forward if there are big unanswered questions.
Lori Walsh: And if the study restarts, does that mean that it was not related to the virus itself or what do we know once that happens about the actual product?
Dr. Susan Hoover: Right. The company is of course not sharing a lot of details about the illness itself due to the privacy of the study subject. But the fact that it was a resumed would suggest to me that the conclusion was that this event or illness was not related to the investigational product, meaning the vaccine.
Lori Walsh: I was reading an article this weekend. And again, we get ahead of our skis because we can all read these things and we all are reading these things, but we don't really understand them yet. So that's why I'm bringing it to you. And it was something about a study in China where they were, the hypothesis was with so many people wearing masks that the viral load is being cut down on. And it can possibly act a little bit like an immune response because you're getting a small dose of the virus through the masks, but then you're not really getting sick or you're only getting sick a little bit. So it was this whole idea of whether masks can act to promote immunity and it was just a hypothesis, but it was through the New England Journal of Medicine. And I'm wondering if you know, can you speak to anything about that idea of masks and immunity? Is that something worth exploring? Is that far off in left field?
Dr. Susan Hoover: No, I don't think it's in left field at all. It's based on the idea, as I understand it, that getting a mild case of an infection might produce immunity and protect a person from a future severe case. So the idea seems to be, the main reason we wear masks is to protect the public from us. So to contain our own secretions in case we might be excreting virus, but another benefit might be of course, that the mask is filtering the air and reducing the amount of potential virus particles we might be taking in. So I think it would be a way to perhaps convert a high inoculum infection if you were so unfortunate that an infected person coughed in your direction, for example, to convert that to a low inoculum that maybe only a few virus particles get through your mask and you would get a mild or maybe even a asymptomatic infection that would lead to immunity. So it's certainly something that's worth thinking about and pursuing, and is hard to really prove at this stage, but it's not from left field. I think it's based on our experience with viruses and the immune response to them in the past.
Lori Walsh: That's interesting. What do we know about reinfection of SARS-CoV2? Where are we at with understanding if once you get it, as I was at, it was with someone who had already had the virus this summer, not too long ago, we were socially distanced and in a big open space, but she was wearing a mask. And I wondered does she need to, because she's already been infected with this. What do we know about reinfection for people who've already had it?
Dr. Susan Hoover: That's a great question and a very hot topic, both in the public and in the scientific community right now. So far out of nine months experience, it seems that re-infection is not common at least within these first nine months. There have not been certainly large numbers of cases where it could be really proven that a person had had COVID-19, recovered completely and got a separate illness related to a re-infection. Lately there have been a couple of cases published, one from Hong Kong and one more recently from Nevada in the United States that are a little bit more convincing. The Nevada case in particular, it was something like a couple of months apart, a person recovered and then got another infection in which he actually became sick. And he happened to be near an institution, the University of Nevada, where they could really do a lot of genetic studies on the virus.
And they showed pretty convincingly that the virus from the second infection was really different from the first one. And it would be very unlikely the first one had changed into the second one. So that is certainly a hot area for further study. I want to emphasize though, that that's one case out of the millions of people who've been infected. So I think it would be fair to say that it doesn't seem to be a common or widespread thing to become reinfected. So we have to tell people that we just don't know yet. And in particular, some people have been infected and had their blood tested for antibodies and found that they had antibodies to this virus. And we have to say to them that that suggests you've been infected. It's certainly interesting to know, but we can't at this point, make any recommendation that people should consider themselves protected from re-infection. I know that we will learn more as time goes on and we have more experience with this virus.
Lori Walsh: I want to revisit, Dr. Hoover, this idea of herd immunity, and basically what it means to us now at nine months into the virus, or really six months in South Dakota, that we've been following it with larger numbers. Now we're heading into fall with this much higher baseline than we had in spring. And people are kind of bringing up this concept again of how many of us who recover, at what point is it beneficial to have that many people recovered, not that we want the people to get sick in the first place. But so can you explain how we should be thinking about this concept of how many people have recovered and what that means for the rest of us?
Dr. Susan Hoover: Yes. So the concept of herd immunity is that if most people in a population are immune, that prevents the illness from circulating, and it allows us to protect those who are maybe not able to take a vaccine or who do not respond to the vaccine by creating immunity. So it allows us to protect the more vulnerable in our society. And in general, herd immunity has been produced by using very effective vaccines. So measles vaccine, for example, is highly effective. Well over 90% and immunities either from the illness or the vaccine seems to last a person's lifetime in most cases. So to achieve real robust herd immunity, you generally need a very effective vaccine and relying on natural infection to produce herd immunity besides being possibly dangerous, as you mentioned, Lori, because some people become very sick and even die. So that is probably not an acceptable price to pay for her to immunity. Sometimes that type of infection doesn't produce a longstanding or long lasting strong immunity enough to really ensure protection of the population.
Lori Walsh: Let's talk about this baseline that we have right now, as we look at South Dakota, North Dakota, the per capita cases, rising faster than other places in the nation. And now we're heading into cold and flu season and school and college and things happening. Another large event coming up with hunting season and some kickoff events in the city of Sioux Falls. Does this baseline of prevalence in the community matter for what kind of fall and winter that we have? Tell us a little bit about what we can expect going forward, if we don't figure out how to make those numbers go down instead of up.
Dr. Susan Hoover: Well, I think we have largely figured out how to make the numbers go down. It's not easy, but it has definitely been done, which is to prevent people from going to large indoor gatherings of people they don't know. And this is really a hard thing to do. It's not easy on us, but places that have implemented reduction in the number of people allowed in a gathering, reduction in things like indoor dining, indoor bars, large groups of people, having emphasis on wearing masks and hand hygiene have really reduced their transmission tremendously. So looking at places like New York state and New York City show us that it's possible, and people there are just as human as people in South Dakota. We all have the same sort of behaviors and desires. And we in South Dakota reduced our rate over the early part of the summer, so we know that it's possible. We know what we have to do. And unfortunately it's kind of day in and day out work and awareness for all of us. Where am I going? Who am I going to see there? Who am I going to potentially infect? And how do I keep myself and my community safe?
Lori Walsh: What encourages you right now, as you look at the science, as far as moving forward into a time that we can recognize as, I mean, are you looking forward to normal in the sense that we go back and do some of the things that we used to be able to do? Are you looking forward to just people understanding more and making those are daily habits? Tell me as a doctor and as a scientist, what are you optimistic about in this fight against COVID-19?
Dr. Susan Hoover: I am looking forward to normal. I don't know when we will be going out and doing our usual activities, but I think there are definitely reasons for optimism. There are, like we talked about at the beginning, there are promising candidates for vaccines, and they've been accomplished in a short period of time, thanks to just lots of attention and effort and funding put on this. So we're in a position where we can start to evaluate some vaccines that at least in animals seem promising in terms of preventing reinfection. There's also the concept of herd immunity, that the more people who are immunized, the better protected the population will be. And there's the hope that if a person is infected, they may not be completely protected from re-infection, but at least the second illness might be milder and has been shown with some of the common cold viruses that their second illness is not as bad as the first.
And so that might reduce the burden of this on our community. And we might be able to look forward to someday to the idea that this is another seasonal virus that circulates, and some people get sick and stay home from work, but nobody dies. Nobody needs a ventilator. It doesn't take such a large toll as it's taking right now. And finally, one thing that encourages me is at least in monkeys, infection completely prevented re-infection. And that was over a short time period, but it appeared that there was robust immunity when these monkeys were deliberately infected a second time. So I think there is reason for optimism in the longterm, at least.
Lori Walsh: And we mentioned at the beginning that you also specialize in travel medicine. And I'm just wondering if you think that, it seems to me that some things I will never look at the same way as I looked at before. And when you take that to a global scale and think about us all getting back on airplanes and traveling for work and for leisure and to visit families, do you think it will be different and is different in this case kind of a good thing, because there does seem like there were a lot of things that we were accepting of before that maybe we didn't have, that we could do better. We could have fewer deaths from the flu, for example, if we took more precautions. Do you have hope for some of the things that we're learning today to be implemented into a new normal that could save lives?
Dr. Susan Hoover: Oh, definitely. And I miss traveling myself very much and I feel bad for all the patients who would come to our travel clinic with big plans for their trips and which have now completely changed. But I think as you say, influenza transmission could be really reduced by some of the things we've been doing to reduce COVID-19. In the southern hemisphere where the flu season is opposite to ours. They have really reported a very mild season last winter, which is our summer months. So that's encouraging and I think it may not be just closing schools and things like that. It may be the ordinary activities people do like washing their hands, avoiding large gatherings with close contact. I think we are learning a lot from that. As you know, this is all over the world now. There are many countries with high prevalence.
So I don't think we're going to be thinking in terms of we can't travel to this or that place because we in the US have as high a rate as any of the highest in the world. But I think travel will just have to resume. We humans want to see each other. We want to have contact. It's not in our nature to remain apart all the time. So I think it'll involve some modification of what we've been doing to make travel safer and some acceptance of risk. And at this point, I think while we understand so little, the risk is unacceptable that we would risk people getting so sick and dying. But I can see a future, as you mentioned, where we have more precautions around travel. We're not so blase about entering a small enclosed space with lots of strangers with maybe not as good hygiene as we could aspire to. So, yes, I think there's reason for hope, this can't be a permanent situation, that humans will find a way.
Lori Walsh: Dr. Susan Hoover, humans will find a way. I like that. Let's just hang our hats on that for another day. Wash your hands, watch your distance and wear your masks, South Dakota. We can turn this around. Thank you so much for your time. We appreciate it.
Dr. Susan Hoover: Thank you. A pleasure talking to you.