Episode 168: Better Times

Chris Dall: Hello and welcome to the Osterholm Update, a podcast on COVID-19 and other infectious diseases with Doctor Michael Osterholm. Doctor Osterholm is an internationally recognized medical detective and director of the center for Infectious Disease Research and Policy, or CIDRAP, at the University of Minnesota. In this podcast, Doctor Osterholm draws on nearly 50 years of experience investigating infectious disease outbreaks to provide straight talk on the latest infectious disease and public health threats. I'm Chris Dahl, reporter for CIDRAP news, and I'm your host for these conversations. Welcome back, everyone, to another episode of The Osterholm Update podcast. Over the past year on this podcast, you may have noticed that we've been expanding the range of infectious disease topics we cover, both by choice and in response to world events. We live in a world where an infectious disease outbreak thousands of miles away can quickly become a threat in our own backyard. And we don't have to look too far back to be reminded of that. While we still spend a large amount of time on COVID-19 and will continue to do so. Outbreaks of infectious diseases around the world from H5n1 avian flu and US dairy cattle to Marburg virus in Rwanda have required us to broaden the scope of this podcast. To provide you with the information and context you need to understand what's going on and why it matters. So in this October 17th episode of The Osterholm Update, as we always do, we're going to start off with an update on COVID-19, but we'll also bring you the latest on H5n1 and the Marburg outbreak in Rwanda. Discuss a recent CDC report on flu vaccine efficacy. Take a look at the latest long COVID research, answer ID queries on COVID vaccines in Marburg, and examine the explosion of dengue cases in South America. And as always, we'll bring you the latest installment of This Week in Public Health history. But before we get started, we'll begin with Doctor Osterholm's opening comments and dedication.

Dr. Osterholm: Thanks, Chris, and welcome back to all the podcast family, to another edition of trying to figure out what's important in public health infectious diseases for you. And I also want to welcome anyone who may be coming to the podcast for the first time. I hope we're able to provide you with the kind of information that you're looking for. As you noted in the introduction, Chris, one of the challenges we have putting together this podcast is actually determining what do we try to squeeze into an hour, what is helpful to our listeners in terms of what it means to their everyday lives? What is it? That's the curiosity that's happening somewhere halfway around the world, but nonetheless is a real interest. And so we're continuing to explore that. And we always welcome your feedback, always welcome your feedback of what topics we could or should cover, what it is that you've heard enough about and we can do less of. And so think about that. And again, this is a podcast family. We've come to understand the importance of sharing of information. And so we do look forward to hearing back from you about this. But before we get into all the topics that you highlighted, Chris, I want to take this dedication segment to acknowledge and extend our deepest sympathies to those across the country who are suffering from the aftermath of extreme weather events. It's been sobering to see how much destruction Hurricanes Helene and Milton brought to the southeastern part of our country. It will take a long time to fully realize the scope of the damage inflicted by these storms, but it's already been reported that over 230 people were killed in the six states hit by Hurricane Helene, and that more than 3 million Floridians lost power in the wake of Hurricane Milton.

Dr. Osterholm: Between the news coverage of lost damage and recovery, there's been another threat of report catching my eye. Climate experts have been weighing in to describe just how much climate change and warming ocean temperatures contributed to the intensity of these storms. The hot water temperature in the Gulf of Mexico helped Helene and Milton intensify to high category storms very quickly. Warming air temperatures brought higher rainfall totals, and modeling showed that climate change drove maximum wind speeds to about 11% more intense in the case of Hurricane Helene. The World Weather Attribution report on climate change effects on Helene concluded that worsening climate conditions will lead to more and more frequent, devastating, larger hurricanes than we've ever seen in the past. This group came to similar conclusions when assessing the impact of storm bores that ravaged Central Europe in September. The extreme drought in agricultural regions of Italy, and this summer's super typhoon Carina that hit the Philippines. Climate change is increasing the frequency, scale and devastation of extreme weather events around the globe. The alarm bells of climate change could not be ringing more loudly. First of all, we recognize in many parts of the world, due to precipitation related issues and warming temperatures, mosquito vectors are now in population levels not previously seen, at least any time in modern history in many parts of the world, and climate change is contributing to that.

Dr. Osterholm: We also can see the issue as related to water quality, and the fact that flooding events like this end up not only causing great physical damage, but also putting people at risk for unsafe water supplies or lack of sewer. And of course, we can't neglect to think about heat related injuries and deaths, which we're seeing mount every year in terms of the increasing temperatures and humidity. And finally, it's mental health concerns related to property damage, displacement or stress. Climate change is clearly a public health issue, and in public health, we know the importance of addressing upstream factors to drive downstream impacts. So as the federal government assesses the cost of the damage, states allocate resources to areas in need and individuals try to put their lives back together. We must also change course. It's crucial that we not only support immediate relief efforts for those affected by these disasters, but also take a hard look at the upstream issues that contribute to these crises. Climate change is not just a distant threat. It's here. It's now. It's impacting vulnerable populations the hardest. Our response needs to go beyond short term aid. We must advocate for systemic change, invest in sustainable practices, and push for clean energy policies that address the root cause of climate change. To do anything other than that guarantees that our future will look even bleaker than it does today with regard to these very, very tragic events.

Dr. Osterholm: We keep tackling these difficult, consequential topics on this podcast and in the rest of the work we do at CIDRAP. Our hearts and minds go out to all the victims of the recent tragic storms, and to all those who are affected by the threats that climate change brings. One issue that we can talk about that is not impacted by climate change, other than allowing a certain amount of it's heat to radiate to the Earth, and that's our sunlight. Yep. We depend on that sun. And today, here in Minneapolis Saint Paul, sunrise will be at 7:32 a.m., sunset at 6:23 p.m.. We're now down to 10 hours, 51 minutes and 31 seconds of sunlight. Today we'll lose about three minutes of sunlight. And between now and the winter solstice, we will end up seeing those days get shorter and shorter. The good news is, the rate at which they get shorter also begins to get lower. And while we're seeing reduced sunlight, our dear friends and colleagues in Auckland, New Zealand, particularly those at the Occidental Belgian Beer House on Vulcan Lane, are seeing brighter and brighter days. Today the sun rises at 6:34. Sunset at 7:39. They're now up to 13 hours, five minutes and six seconds of sunlight, gaining almost two minutes and 17 seconds of sunlight a day. Yep. Wish I was in Auckland for a couple of hours today. But you know what? It's great to be home.

Chris Dall: Mike. The CDC's COVID indicators, including early indicators like test positivity and severity indicators like hospitalizations and deaths continue to trend downward. But the XEC variant, which isn't covered by the updated COVID vaccine, is on the rise. Is that a concern for the coming months?

Dr. Osterholm: Well, Chris, let me just hit to the bottom line immediately. Right now in the United States. We are experiencing really the lowest level of serious respiratory disease in our communities than we have probably at any time in the last 5 or 6 years. Fortunately, we're seeing COVID numbers come down, and I'll talk more about that in a moment. But we're also seeing very little evidence of flu activity and respiratory syncytial virus. Rsv is also at a relatively low level. And so for those who can tell, I have a little bit of laryngitis today because I picked up some bug, not COVID, and I'm doing just fine, thank you. The point of this being, however, is that right now we should remember these days as what it was like before the pandemic, because that's what we're experiencing right now. They will change. Surely we will see more stressful days ahead. But from this perspective, with the respiratory illnesses that we worry about, the ones that can hurt us and kill us, we're in pretty good shape. Now, having said that, Every death is a critical death when it's one of your loved ones, when it's one of those you care about someone you work with. So as I share the information on COVID today, I don't want it to come across as if somehow it doesn't matter anymore. It does matter. But fortunately again, we're seeing some of the best days in our communities since our last episode.

Dr. Osterholm: Chris. COVID activities continue to decrease across the board. Wastewater concentrations are decreasing in every region of the country, and the national wastewater concentration is considered low for the first time since June. All the severity indicators, including hospitalizations, emergency department visits and deaths are also down this week, which is great news. There are about 3500 Americans hospitalized with COVID-19, in the 32% of hospitals that reported their data last week, and around 12% of those hospitalized are in ICUs still a concern. We're nearing November 1st, First, which is when health care organizations in this country will require to report hospitalization numbers again like they did during the pandemic. However, using a rather crude assumption that these 32% of hospitals that are currently reporting are representative of all hospitals, we can approximate that about 9000 to 11,000 Americans are currently hospitalized across the country for COVID-19. Still big numbers if you're one of those hospitalized. Last deaths are also down, but not below the 1000 mark. Yet this past week, there were 1189 deaths, and that marks the ninth straight week with more than a thousand deaths. It's the 14th straight week in the US deaths above 500. Now, I think the good news here is with each successive podcast, you're going to hear, at least for the next month or two, these numbers continuing to drop and drop precipitously. So again, for any of you who know someone in those 189 deaths this past week, someone you love or care about, it's really significant.

Dr. Osterholm: But when you think about where we were and how we've changed, this is remarkable. If you look back into the pandemic in July of August of 2020, 8000 deaths at a low point, when just a few months later, in January 2021, we were back up at 25,000 deaths in a week, and we actually saw numbers 21,000in January of 2022. So at this point we are much lower, but that too is still not acceptable. And why do I say that? Because when I look at the deaths that we see, to date, 97% of those deaths are in those 55 years of age and older. And unfortunately, many of them have not recently been vaccinated. Now, again, vaccines, as we've talked over and over again for COVID, are not going to keep you from ultimately getting infected. They will protect you for a limited period of time, but in fact, you can greatly reduce your risk of serious illness, hospitalizations, and deaths even in the older age population by getting your dose of vaccine. I'm very happy to report that this past week I got my next COVID dose, and I'm feeling really good about that. It's been almost four months since I had my last dose, I got it. Also, just to let you know that the ACIp in their upcoming meeting are going to actually take up the recommendation for an additional dose this winter.

Dr. Osterholm: In particular, for those of us who may have risk factors for more serious illness. So I realize for many people, they will not continue to get vaccinated every few months. But for me, it's a small price to pay to keep me out of the hospital and being seriously ill. Now, you mentioned the XEC variant and this is a concern and I don't know where this is going to take us, but in fact, this is a new variant unlike any we've seen before based on where the mutations are. It's not just on the spike protein. This is actually a recombinant mixture of two different subvariants. CS.1.1 And CP3.3, which are both JN.1 Subvariants. I'm sure for many of you that doesn't mean a lot, but what it really is talking about here is that it still is in that same lineage of viruses for which we've been vaccinating against. And so I do expect the vaccine to actually be still as effective here as it was with some of the other variants. What's very different here, though, however, is what you might say is the speed at which it likely can spread through the population. It will get around the immune protection that we may have enjoyed in the past with our vaccines or previous infection. So at this point, I will say the take home messages. Number one, the XEC variant is going to potentially mean more transmission in the community.

Dr. Osterholm: Again, with what we have for background immunity from those who were infected during the August September time period, and we saw lots of Americans infected. And with those getting vaccines right now, there will be some good protection for some time against this. It's those who haven't been vaccinated recently who haven't been infected recently. Boy, I sure urge you to go and get your, uh, booster as soon as you can. I want to add one more comment here, and I'm sure not everyone will appreciate this, but I have become aware of a number of major outbreaks of COVID in the last 4 to 6 weeks among individuals taking cruises in different parts of the world, both here in North America as well as in Europe, and the cruise ships by themselves create a very unique world where you're all living closely together. The ventilation inside many of the ships means you end up swapping air more frequently than you realize. And so I just would urge anyone who is going on a cruise in the upcoming days to weeks, make sure you're up to date on your vaccines, both influenza, and I'll comment on more of that later. And your COVID vaccine. Uh, too many people have gone on cruises, had a horrible experience, only to find out that, you know, they should have and could have done more to protect themselves before they left by getting vaccinated.

Chris Dall: Mike, as you know from both the data and your own personal experience, any SARS-CoV-2 infection comes with the risk of long COVID. So is there any recent long COVID research that you think is worth noting for our listeners?

Dr. Osterholm: Well, in general, I would say, yeah, we have a lot of work to do, but when you look at what kind of information has come forward in recent studies showing the critical importance of inflammation, we really are starting to hone in on, I think, on possible mechanisms for which long COVID can occur. And let me be really clear about this. There isn't a one long COVID. We're finding that there are multiple different sequelae or long term impacts that occur, and they can be very different. And some of us have one, some of us have another. When you look at where we're at today in the research, what we're really looking at is what does this inflammation do, this, this immune response to the host that gets turned on because of its interaction with the COVID virus. What does this mean? And I think this is where we have the real opportunity in the days ahead, not only to make a big impact on the long term impact of long COVID with COVID cases, but also for a number of other infectious diseases from those who are suffering from other viral infections CMV, Epstein-Barr virus, those who have been infected with Brugia burgdorferi, and Lyme disease.

Dr. Osterholm: Again, the inflammation piece has played a huge role. The body gets turned on, it doesn't shut off or shut down. And then as a result, we see these other health conditions. So there is one study that actually this past week addresses this. And I'd like to share that with you today. It was conducted by researchers in the UK who used MRI scans to assess brain inflammation following severe COVID-19. The researchers compared brain images of 30 participants that had been hospitalized with severe COVID-19, 3 to 18 months prior to the study, to 51 age matched controls who did not have a history of SARS-CoV-2 infection. The researchers found that those who were hospitalized with severe COVID had inflammation in their brainstem, which is often referred to as the control center of the brain. Those who had longer hospital stays, more severe acute infections, and worse functional outcomes were more likely to have greater inflammation. This study adds to the growing body of evidence. I just talked about, suggesting that chronic inflammation plays a key role in the pathology of long COVID. Though this doesn't give us any immediate answers for those suffering. Understanding the role of inflammation and how we might modulate it is a really important step to eventually developing therapies that can help patients right now.

Dr. Osterholm: For those interested in learning more about this study, we will link a CIDRAP news article that covers it a bit more in detail in our episode description. And finally, as always, I want to remind our listeners who are suffering from long COVID. We are here for you. We are listening to your stories, and we will continue to advocate for the research needed to find answers for you. I can tell you, after my six months of long COVID, I absolutely understand what it means to have that condition. When you wake up in the morning and when you go to bed at night. And so we will continue to push this topic, and I urge you to continue to follow our CIDRAP news, because oftentimes in the hour that I have with you now, I can't get all of these articles summarized and into the podcast, but you can read them on our website free of charge. Nothing of CIDRAP should ever cost you a penny except your time, which we know is valuable. But in fact, I hope that you're able to go and check out these stories.

Chris Dall: Mike, as you noted, we're still not seeing much seasonal flu activity yet in the United States, but a recent analysis by investigators in five South American countries found that the 2024 seasonal flu vaccine's efficacy during the Southern hemisphere's flu season was only 35%. How concerned are you about that?

Dr. Osterholm: Well, Chris, it's not actually a surprise. This is a challenge that our group has been very aware of for more than 12 years. When we published our seminal article back in 2011 on this very topic. We have for a long time thought of influenza vaccine as like a measles vaccine. Once vaccinated, long term protection that would cover you through not only the season, but against a variety of different potential influenza strains. It's not the case, but let me remind you what I've said over and over again. Influenza vaccines are good vaccines. They're not great, but they're good. And what do I mean by that? They're good in the sense that if you look at what's happening with vaccination and illness, any given season, you may see somewhere between 25-35% up to 40-45% protection against what we call medically attended illness, i.e. a doctor or a nurse seeing you or even hospitalization and death in this case, this vaccine study, which was conducted by researchers in Argentina, Brazil, Chile, Paraguay and Uruguay, actually found a 35% reduction in hospitalization against influenza, which I'll take any day of the week. That's worth a shot to me if I can get that kind of protection. Now, we've talked about the situation with regard to when you get your vaccination, because in fact, we see anywhere from 2 to 12% reduction in that protection from the month.

Dr. Osterholm: You get it by month. So in the first month, I may lose 2 to 12%, the second month another 2 to 12%, the third month, another 2 to 12%. And that's why you heard me say over and over again, don't get your flu shot in August and September, even early October. Well, as I just shared with you first, the fact is that we're not seeing flu activity right now. That remains a very low level concern in the community. All 50 states and the District of Columbia have reported levels of seasonal influenza activity deemed minimal by CDC. This is good news, but it's not going to continue. We will see flu and the fact that the vaccine we're using in our country now is the same one that was used in the Southern hemisphere for their winter, i.e. last summer. For us, that means we're surely not going to see any better protection against hospitalization than they saw. So the point being here is, is that when do I get my flu shot? As I noted at the early part of the podcast, I got mine this week. Why? Because first of all, it's a challenge to get into some places right now to get a dose of vaccine and so you can count on up to a week to ten days before you can get in and be scheduled for it.

Dr. Osterholm: Number two, it will take you, you know, 7 to 14 days to really begin to mount that immune response. So that's about three weeks out. I think that is the safe place to be right now. I don't think we're going to see this big burst of flu activity, but I can see it picking up by mid to late November. So to anyone who had a question about when is Mike going to get his flu shot. He got it this week and I'm happy to have gotten it. So I got both it and my COVID booster. So at this point, let me just reaffirm that we're in good shape with flu activity right now. Lowest level in conjunction with the other respiratory viruses we've seen in many, many months. But now is the time to get ready for what surely is going to be a flu virus that will return. And we now have some time to get better prepared for it without also, in a sense, wasting our immune protection by not being in that flu season for months and months.

Chris Dall: Let's turn to H5n1 avian flu. California has now reported 11 H5n1 cases, all linked to contact with infected dairy cattle. Mike, are there any differences that we know of between these cases and the human cases that have been reported in Missouri?

Dr. Osterholm: Boy, Chris, I could spend the next hour on this topic. Um, it's one that I have to upfront say I'm probably in a contrarian position on, and I'm not necessarily in sync with some of my colleagues and surely not a number of people in the media. Let me just remind everyone that where we're at right now, we're continuing to see evidence of H5n1 virus activity in milking cows throughout the country, but specifically in California. There are now 305 herds in 14 states that have been documented to be infected. That includes 105 in California. 34% of all the herds. If you look at California, Colorado, Idaho, Michigan and Texas, those five states, they account for 258 of the 305 herds that are infected, or about 85%. And these numbers are going to keep changing by the time this podcast is published and you're listening to it. We could already see another increase in herd document. So this is a challenge inside the dairy industry. And it's a challenge now that we're learning, particularly in California, is of great consequence to the dairy industry at this point. We're seeing increased mortality in the cattle. We're also beginning to realize that they have a challenge in coming back to milking production levels that they had before. And when you look at what's happening in California and in specific, you know, the state that is basically responsible for 20% of all the milk produced in the country. You can see the affected farms run from north to Sacramento, all the way through the Central Valley and all the way to LA.

Dr. Osterholm: That's a remarkable level of infection occurring, and I expect you're going to see more. Also, we're now at a very critical time of what is beginning to be the next season, you might say, of milking cow activity. Well, what do I mean? Well, most people don't realize that there is a timing to a cow being milked. And when they're able to produce milk, it's typically a situation where a dairy cow milks for about nine months. The milk production is initially stimulated by the birth of a calf. It then ramps up in the weeks after birth, peaking at about week 6 to 10, and slowly tapers off for the next several months. And then at that point it goes into a new cycle. The cow is then impregnated again roughly two months before she is to give birth. Again, she's taken out of the milking barn and as they say, she is dried out. After that, the birth is given. They put her back into the mix. So when we are looking at this issue, we're not sure what's going to happen in these periods of transition from being impregnated, delivering a calf, stimulating milk production, then being milked continuously until the next cycle starts. And there is some real concern as to what that milk production level might look like. So they have to get this down. Now, from a human standpoint, this is where it gets more interesting.

Dr. Osterholm: You might say, in terms of our immediate concern, if you're not a dairy farmer, is the fact that what risk does this play for humans? You know, I have shared with this audience on multiple occasions my long and tortuous career with H5n1 dating back to the 2003 2005 time period in Southeast Asia, and I have been very involved in a number of areas with H5N1 since that time. Between January of 2003 and July 19 to 2024. So the data are about two months old. There have been 896 cases of human infection with H5N1. 463 or 52% were fatal. Now that's a big number. But if you look at how that was distributed over time, it tells us a lot. For example, if you look at at case numbers in the early days, we saw, for example, after the return of the virus from its original impact on Hong Kong in 1997 and then starting to spread in Southeast Asia in 2004 or 5 and six, we got up to 98, 88. 115 cases a year of what is truly classic severe influenza A pneumonia like illness, not just an eye infection. I'll come to that in a minute. And then we watch those numbers decrease each year over time, primarily in Southeast Asia and Asia in general, such that by the time we got to 20 1213, we were talking about less than 40 cases a year in humans, isolated cases. And then you may recall, as I shared with you before, 2012 was kind of a wake up call moment when two of the really respected researchers in flu work in the world presented data to the National Science Advisory Board on Biosecurity, of which I was a member, saying we were only 1 or 2 mutations away from H5N1 causing the next pandemic.

Dr. Osterholm: You know, you could just feel the hands gripped tightly on the chairs as they saw those data. Well, nothing happened until along comes 2015, and 145 cases suddenly appear in the Nile River valley, of which half died. They were largely among duck farmers. And then, just as quickly as that happened, it went away. And if you look at the period of time from 2017 to 2020, for a seven year period, there have only been 33 cases and 11 deaths documented of human H5n1 infection. Now the US numbers will be added to that where today we have more cases I'll talk about in a moment, but they're not the classic influenza like illness. What am I talking about? Well, as I've also shared with you, over time, the avian flu viruses have a type of sialic acid binding preference, meaning where the virus can bind to a cell and infect that cell, i.e. infecting whoever owns that cell. And in this case, the sialic acid two three binding, which is the avian binding, has surely been a challenge, particularly with the new clade of virus out there. Truly dramatic impact on mammals as well as avian species. Ironically, virtually no impact on swine, which is a very key animal for us because they have the two six sialic receptor sites.

Dr. Osterholm: So when they look at this infection, we're not seeing two six binding site infections. Those are the ones that you'd expect to see from infection in the lungs, where there's two six receptor sites are at and where we would expect to see people developing the severe, life threatening infection. And so as we've watched the summer unfold, we're now up to 25 cases in humans, all who have contact with either the infected dairy cattle or birds, with the exception of one And all are largely conjunctivitis in the eyes. The human eye has two three receptors in it, as well as two six receptors in our respiratory tract. But we're not seeing respiratory tract illness. And so I'm not convinced that H5n1 is ever going to get over the bar to cause a human related pandemic. Yes, we'll have these one off or two off kinds of cases, meaning that we'll get transmission from an animal to a human and then possibly one more generation. But I don't think it's going to go. Now, I could be wrong and it could happen tomorrow. We could see a reassortment event occur where now we know that the bovine udder has receptor sites for two six and two three, and that in fact, we could see a situation where a individual working in the barn is infected with, uh, influenza and somehow contaminates that udder, causes udder infection, as does the H5N1 that's already there.

Dr. Osterholm: We could have that happen, but for some reason, since 2003, 21 years, we have not seen that happen in humans, even though H5 has gone through a number of changes. So at this point I will just say one, there's going to be more influenza pandemics and they could be a hell of a lot worse than anything we've seen to date. So please know I'm bullish on pandemic preparedness. Number two, there is something about H5N1 in humans that I don't understand. And when I talk to many of my colleagues who are real flu experts, they also will tell you they don't know what's happening or what the likelihood is of H5N1 causing serious illness in humans. And we can't confuse when we call a bird flu case one that has conjunctivitis only as really true bird flu. From my perspective, that is an eye infection. The virus lands in the eye. It has the receptor sites. And if we look at even the data on, can we pick up the evidence of their infection in one's blood? I mean, serology or antibody response, it's mixed. And that was based on data from an H7 outbreak where people with conjunctivitis didn't always even have an immune response that could be picked up in the blood. It was all isolated in the eye. So a long, long winded answer here to say one I am concerned about what's happening with the cows. I think that yes, we want to get rid of that as soon as possible, and the dairy industry should be in the lead in that.

Dr. Osterholm: For all the implications of what it means to their industry. Number two, we have to continue to look closely at what H5N1 is doing to people. We likely in the next two weeks, we'll get information from the CDC studies looking at the individuals with respiratory illness in Missouri, where we had one case of H5n1 infection documented. I've stated before, I think in the end, none of those additional contacts that had some respiratory illness actually had H5n1. But we need to keep looking at that. So at this point, I think we need to back off a bit. I've watched too many journalists, some colleagues who have been out there, you know, not quite screaming, the theater's on fire, but darn near we don't need to have this happen to motivate us to get better prepared for a pandemic. But I will tell you, if we keep saying this is going to happen and going to happen and it doesn't happen, just like I watched in 2012, we are then going to be held holding the message that, oh, you just scared us needlessly again. So we've got to find the right message level. Pandemic influenza is critical to be prepared for. Our vaccines need a heck of a lot of work to get better prepared. But in fact, whether this one will do it or not, we just don't know.

Chris Dall: In Rwanda, the Marburg virus outbreak is now at 62 cases with 15 deaths. Rwandan officials say the outbreak is under control. But last week, the CDC issued a travel advisory that urged Americans to reconsider nonessential travel to the country. The CDC said it will also begin screening travelers from Rwanda. So, Mike, two questions. Do you think this outbreak is under control? And secondly, do you think that travel warning was warranted?

Dr. Osterholm: Well, I don't know if the outbreak is yet really under control, but I would say that we were very fortunate. If that is a word you can use here, that it actually happened in Rwanda, because they likely have the very best health care and public health systems in all of Africa. They're extremely good at what they do. And they were on top of this right away. And again, from a community risk standpoint, the majority of the cases of severe illness and of concern were actually in healthcare workers who were exposed to the individuals who presented with illness and being admitted to the hospital. So I think from that standpoint, um, you know, we're in good shape relative to the ability to control it. We're now watching vaccine roll in. There are over 700 doses of an experimental vaccine that's been administered in Rwanda so far. Using that classic strategy that we talked about so many times before use for smallpox eradication, ring vaccination, vaccinate around those who are at highest risk of having been exposed to a case. We saw that same success work with Ebola. So let me just come back and say, yeah, I think we're going to have this one under control soon. But I do have a challenge with the issue of what the US did with its warning and how it put that out.

Dr. Osterholm: Why do I say that? Well, because first of all, we have watched this happen time and time again. It happened with Omicron in South Africa. It's happened with Ebola. It's happened here where when you put any kind of travel restrictions or even just a warning out, as such, it causes that country that announced its challenge or its outbreak to suffer economically from trade and travel in general. And in this case, there was no immediate danger to citizens traveling to Rwanda who were not in the same kinds of population centers where this virus was located. And so, from my perspective, and I come back to this time and time again, we should save those kinds of recommendations for border closings or travel restrictions, if, in fact, that's going to make a difference. And we don't have any evidence these make any difference anyway. We just don't. And so what it does is it penalizes the country. Now if I'm country A in low income country category and in fact I have a disease outbreak, why am I going to be speedy to report that if I think I'm only going to be punished for it? So we have to look at what is really happening. And I look at the inconsistency. And I picked this up because I think it also points out that we have to be careful not to respond to what we call media related need for doing something.

Dr. Osterholm: Lassa fever is an also another major challenging disease in Africa. It's one where it's located in Western Africa, in a series of seven countries where the primary reservoir is a mouse, the Mastomys mouse. And it's one that actually likes to live in in domesticated locations, i.e. it wants to like rats and do in our country, live in the household area where garbage, scraps, Etc.. The mastermind carries this zoonotic virus that if it's in the urine and you either come in contact with that, you're in a physical environment where you're cleaning up, you inhale it. You basically have a situation where now you're at risk for Lassa fever. And when we look at Lassa, it's a disease for which it's estimated that there are 100,000 to 300,000 Lassa fever cases a year across West Africa, including 5 to 10,000 deaths. Now, these numbers may be slightly higher or lower than some challenge to that, but this is a bad disease and I haven't heard anyone talk about, well, we need to put a warning out not to go to these countries because of Lassa. And this actually dwarfs the entire risk of Marburg, which is not insignificant. But when you're concerned about Lassa. So, you know, my first logical question as a scientist is if you're going to put a travel warning out for Marburg.

Dr. Osterholm: Why are you not putting it out for Lhasa? And in fact, people will say, well, that's different. That occurs all the time. Well then why do you put a warning out? Is it only if it occurs? Sometimes you warn. And so I think at this point we do need to go back to the drawing board and look at what it is that we make recommendations for or about with regard to border closings, travel, follow up for people overseas, surely provide information, make sure everyone knows what the potential issues are. Knows what if you are infected, what the early signs and symptoms are, what to do to protect others if you are infected. But don't just put a warning out. I think that doesn't help and we'll see in the future. I know if this were to happen here in the United States, somebody could say, right now, you know, we better put a warning out in California, don't go there because they have all that H5N1 infection in cows. And we'd say, oh, that's crazy. You don't need to do that. Well, you know, what goes around, comes around. And I think that's what we want to do. We want to do this on good science, not on politics or public relations.

Chris Dall: It's time now for our ID query, which this week I'm going to call ID clarification since we have two of them. And they both regard things that listeners have heard in previous podcasts and have questions about. So first we're going to hear from Yolanda, who wrote on episode 167 of the Osterholm update. You gave a timeline of 2 to 3 months after a COVID infection before getting the new vaccine. The CDC and some other sources suggest three months or even at least three months. Can you say more about your choice of 2 to 3 months after infection?

Dr. Osterholm: Well, thank you for that question. And and for me to have the opportunity to further elaborate on getting the vaccine. The comment I made in the last episode about getting a new vaccine dose, 2 to 3 months after the previous illness, came in the context of discussing the low vaccine uptake we're seeing in the US, particularly among those 65 years of age and older. The demographic that actually represents, as I pointed out earlier today, well over 90% of all the COVID deaths in September. So you want to focus on that and the fact that we have this new vaccine dose, as I stressed in the last episode, we're trying to keep up with this changing coronavirus. Cdc encourages waiting three months between the last infection and receiving a new dose to capitalize on the immune response you get after a natural infection, and extend that immunity by delaying a booster by a few months. That's a great plan. I endorse the timeline the CDC also encourages, and I agree with considering your personal risk of severe disease, which means that waiting three months may not be ideal. So if you're one of those in a higher risk categories and maybe have plans on your calendar that could increase your risk of becoming infected, it's reasonable to consider timing your dose to align with your circumstances. These decisions are nuanced, and while the three month benchmark is accurate and helpful, not everyone will be able to time their booster shots at precisely 90 days out from their recovery. But ultimately, what's most important here is keeping up with the new vaccine to protect yourself and those around you. And again, if you're just getting an older dose of vaccine, not the newer dose, then I would say timing isn't as important, but getting that newer dose sooner surely is. So I hope this helps answer the question. It's a good one. And you know, at this point I waited four months between my doses just because at this point I saw the COVID activity reduced here at this time. And I'm anticipating that sometime by mid winter we're going to see another spike again in COVID cases.

Chris Dall: And then, Mike, you received an email from a listener who questioned your explanation of how Marburg virus is transmitted. So can you say more about that?

Dr. Osterholm: Absolutely. And this is actually a issue near and dear to my heart. Last week I drew similarities between Marburg and other hemorrhagic filoviruses like Ebola in terms of symptoms and how they spread. Marburg virus disease is a zoonotic, meaning that it can spill over from animals to humans through contact with infected animals like the Egyptian fruit bats and non-human primates. Marburg virus can also spread from human to human through direct contact with body fluids, from someone who is sick with, or has recently died of the disease. It's also possible to contract Marburg through contact with contaminated objects and needle sticks. Health care workers and caretaking family members are at especially high risk of contracting Marburg, primarily when members of these groups do not follow the proper infection prevention practices. More importantly, though, Marburg virus has not been clearly demonstrated to spread efficiently through an airborne transmission route or more brief casual contact. This is another reason the travel restrictions are really misguided here. So the real challenge here is trying to understand does this virus ever transmit via the respiratory route? Well, it so happens that I waded into this very deeply with Ebola virus, which I think is very similar to Marburg. And therefore whatever you discuss on Ebola surely applies to Marburg. And back in 2015, in the middle of the very large outbreak in Western Africa, that many of you may recall over 11,000 deaths, we published a paper in the journal mBio. I was the first author, and it included 20 of the leading Ebola experts in the world, and the title of the paper was Transmission of Ebola Viruses What We Know and What We Do Not know.

Dr. Osterholm: And in short, we found a number of situations where there was surely some evidence of respiratory transmission of Ebola in laboratory situations with animals, i.e. primates. And from this we concluded as a group. And this was all of these experts. In this review, we addressed what we know and what we do not know about Ebola virus transmission. We also hypothesize that Ebola viruses have the potential to be respiratory pathogens with primary respiratory spread. You might have thought that I was upsetting the entire world. Many of my colleagues were not happy with that statement. They felt that it was a scare tactic that this wasn't true. Well, if you read this paper, first of all, take a look at the authors and you'll get a sense of the world's experts here on on the issue of Ebola virus infection. And then you look at the information contained and this article will be linked on the website for the podcast. And it does, I think, support the fact that there has been respiratory transmission of Ebola. How common it is is not clear yet. Surely it's not at all a primary means for transmission, but if it can happen, what does it mean over time? How often would it happen? And could you see a sudden change in in increasing ability to be transmitted via the respiratory route? Now again, I want to point out, you know, we're not saying at this time that Marburg or Ebola viruses are being transmitted primarily through the respiratory route. But, you know, I had people criticize me at the time that this paper was published.

Dr. Osterholm: One of them I thought was fascinating said, look, it once a virus has been established, the way it's transmitted, it never changes. This is ridiculous. It was at the same time that we saw the Zika activity occurring in South America, from which a mosquito borne virus or vector borne virus was now being transmitted sexually. That's kind of a change. And yet and that was right in front and center with us. So to address the issue of Marburg, let me be clear. In this outbreak we don't have any evidence of respiratory transmission. But then I can't say we don't have any evidence that didn't happen, meaning what really took place in the hospitals in terms of personal protective equipment, etc.. How did that happen? Was there individuals that had no body fluid contact, no blood contact that may have become infected? We just don't know. But should we be surprised if we see evidence of respiratory transmission with either Marburg or Ebola? I don't think so. And again, I refer you back to this paper that's linked here. Take a look at it. And I think you'd agree with me that if this can happen with Ebola, there's no reason it can't happen with Marburg. So just to clarify for last podcast. Comments. We have no evidence at this point that Marburg has been spread via the respiratory route in this outbreak. But could it happen much like the evidence we've seen with Ebola? I think the answer is absolutely yes, and we need to be aware of that.

Chris Dall: Now for some other infectious disease news, last week, the Pan American Health Organization said that more than 11.7 million dengue cases had been reported in the Americas region this year, which is more than twice the number reported in all of 2023, which itself was a record year for dengue cases. So, Mike, what is behind the surge in dengue cases in South America, and what does it mean for both the people who live in that region and those who might travel there?

Dr. Osterholm: Well, Chris, this is a complicated issue with this particular mosquito borne disease, and I'll come to that in a moment. But the world and specifically the Americas is in a really tough situation with dengue right now. 2024 has been the worst year on record for this disease. We've seen over a 30 fold increase in the last 50 years. One important consideration for dengue surveillance is that in most otherwise healthy people, first infections with the disease are often very mild, typically causing fatigue and a low grade fever. Most people may be entirely asymptomatic. This means that many, if not most, dengue virus infections go unreported. Severe disease is more likely upon subsequent infections or what we call reinfections. And that might be what we're seeing here. And this is all related to a condition known as immune enhancement. We know that if I'm someone who has previously had dinghy and have high antibody levels against the dengue virus, or I have a vaccine related antibody level, I'll be protected against getting a new infection. If I've never had dengue before, I'll have no antibody. And so in that case, I get infected. But if I have a certain low level amount of antibody, and particularly with certain strains of the dengue virus, that causes a thing called immune enhancement, another one of those immune response issues, like I talked about with long COVID in a sense, but in this case, this can be deadly. The immune enhancement, it causes shock. And that's where you get the dengue hemorrhagic fever picture, where basically people become severely ill.

Dr. Osterholm: And so this is what we're concerned about is we have so much dengue now we're seeing multiple infections over time resulting in many more very severely ill people. The US regularly identifies dengue and travelers, typically those in Latin America, where activity is highest. However, the US and Puerto Rico have identified increased local transmission in the US Virgin Islands, Puerto Rico, Florida and California. So we're beginning to see more and more of that. And this also ties back to the initial discussion we had on climate change. Now the Aedes mosquito, Aedes aegypti, Aedes albopictus, these are mosquitoes that are basically the household mosquitoes. They're day biters. They're very quiet. They bite you behind the neck, behind your knee, places like that. You don't even feel them. They live close to you in discarded plastic garbage that has a little bit of water that particularly if it's hidden in a shade like environment, garbage, is the perfect breeding location for Aids. And so part of the challenge we have right now is that we've seen this major increase in urbanization of many of these areas, and even where there has not been urbanization, there still is lots of garbage, lots of of discarded plastic, which now provides for the breeding site, now with increased precipitation that just keeps these locations. That may be a watering can. They may be any number of things loaded with these mosquitoes living right next to us. The tire temperatures mean that the mosquito virus cycle goes faster. In other words, the mosquito actually becomes infectious after it takes a blood meal on someone who is infected.

Dr. Osterholm: Before then, it gets infected as a mosquito and then feeds on someone else. You can increase the speed of that by having higher temperatures. Now this is different though, than some of the climate change issues where the Culex tarsalis mosquito, a number of other mosquito populations will be influenced a lot by climate change, where bodies of water that now before didn't exist, but with heavy precipitation. Dew creates amazing breeding sites for these types of mosquitoes. So let me just say dengue right now is a huge challenge. If we could clean up the garbage of many areas in the world, we could see a great reduction in dinghy. But where we have that, climate change also can still play an important role in increasing the likelihood of that happening. And I think that this is going to be a huge challenge in the future. And this is one where, again, I would not put a travel warning out to say, don't go, but leave it to your own decision. But I'd want to know if I'm going to an area that has dengue infection in any meaningful level and what I mean by meaningful level 1 or 2 cases in a community. Surely not good, but it doesn't mean you have widespread dengue transmission. But if I'm going to on a vacation or I'm going for work reasons, family visits to a dinghy infected area, I'd want to know that just so I make sure I protect myself.

Chris Dall: Now it's time for this week in public health history. Mike, who are we celebrating this week?

Dr. Osterholm: We actually have a really fascinating person to talk about this week Harvey Washington wiley. He was born October 18th, 1844, in a log cabin in southern Indiana. His family, made up of farmers and preachers, were also conductors of the Underground Railroad, helping to transport people across the border from slave owning Kentucky. Wiley himself fought in the Union Army, finishing the war as a corporal in the Indiana Infantry Regiment. Wiley then completed a degree in Humanities, followed by an MD. He became a chemistry professor at Purdue University and was appointed as the State Chemist of Indiana. Wiley was constantly learning and seeking out new information. He traveled to Germany to study some of the latest in food chemistry, particularly the impact of different food additives on human health. He began to publish papers on the adulteration of foods from milk to canned green beans to sugar. Wiley he was offered the position of chief chemist for the US Department of Agriculture, where he flourished. Using his strong public relations skills and background in agriculture and food industry. At the outset of his government career, Wiley sought to improve food labeling practices so that consumers had more transparency in what they were eating. But Wiley soon introduced the idea that some food additives should not just be listed on the label, but banned from the food supply entirely. Additives like formaldehyde were readily used in the food industry at the time without testing to determine their safety.

Dr. Osterholm: Wiley developed safety trials to learn more about the health impact of substances from borax to salicylic acid. His 12 test subjects, known colloquially as the Poison Squad, brought national attention to the threat of toxic additives. However, his initially proposed food Bill of 1902 did not even make it to a vote before being defeated by lobbyists from major food companies. This did not deter Wiley's pursuit. Wiley began to engage with the population who actually purchased groceries in the US. Women. His campaign took hold with notable cookbook author Fannie Farmer, who championed the importance of, quote, pure food. The tipping point came in 1905 with the publishing of Upton Sinclair's book The Jungle, which revealed the repulsive conditions of the meat industry in Chicago. Wiley, local female activists and some more progressive food companies, including Heinz Ketchup, met with President Theodore Roosevelt soon after the Meat Inspection Act and the Pure Food and Drug Act were passed. Popular press at the time even referred to this legislation as Doctor Wiley's Law. The resulting years of research, enforcement battles, and lawsuits over the safety of various attitudes to food and medicine can fill volumes. Wiley built the foundation for the nation's Bureau of Chemistry, which later took on the name the Food and Drug Administration or the FDA. We owe him a debt of gratitude for putting science first and ensuring that the public safety is above any corporate profit. Thank you, Doctor Wiley.

Chris Dall: Mike, what are your take home messages for today?

Dr. Osterholm: Well, first of all, we're living in a what I would call a better time with respiratory viruses than we have in a long, long time. Rsv, COVID and influenza are at low and dropping levels, but please don't forget that won't continue like that. And for some people, it's even still a risk. Now get those vaccines. Number two get that flu shot. So just to emphasize point one now's your time I got mine. I told you I'd get it when I thought it was about the time to maximize on being able to get in and get it and develop some immunity. And then the flu season come. Uh, the third one is, you know, the Marburg virus will be controlled, I think, soon. Uh, and it's one, though, that we have to keep our eye on all the time because it could take off again any of the filoviruses, Ebola, Marburg, much like we saw back in 2015 to 2016. This is a huge issue. And let me give you a second, third priority. H5n1 virus is going to continue to be a story to be told. I don't understand what's going on. No one really does. And I don't know what risk it poses to humans in the big picture. I surely think it's possible we'll never see a pandemic associated with H5n1, but we could. Now that's a hard line to listen to and say, well, tell us what? What is the answer? And the answer is, we don't know. But what that answer means is that's why we have to be much better prepared for any flu virus to cause the next pandemic, any coronavirus to cause the next pandemic. We will never waste an investment in getting better vaccines and better opportunities for manufacturing quickly when we need them.

Chris Dall: And what closing song have you chosen for us today, Mike?

Dr. Osterholm: Well, this song kind of came to me fortuitously this week. We all recognize it's been a challenge being alive today, just with all the bad news around us. It's almost like we have this terrible, terrible miasma that has settled in in so many parts of the world, and specifically even right here in this country. And so, you know what? I'm one of those people that would much rather smile than feel sad, feel angry, feel scared. And I was actually walking back to my condo that I live in here in Minneapolis earlier this week, and in the distance with rain clouds that I knew were going to miss me, so I had the luxury of watching them. But all of a sudden, in those rain clouds, a big rainbow appeared and it just made me feel so special, so wonderful that, you know what? There's still a lot of good in this world. There's a lot of beauty in this world, even if everything around us seems to be a challenge. And so I had to go back to my old standard here. For those of you who've been long term listeners of the podcast, you already know what I'm going to talk about today here. This particular song has been used three previous times. You'd think I like it, don't you? On December 10th, 2020, in episode 35, The Last Mile to the Last Inch on November 18th, 2021. Remember way back then on episode 78 Breakthroughs and Boosters.

Dr. Osterholm: And then in a very special episode December 29th, 2022, in episode 121. Thank you, Doctor Jena. Part two. And so today, I've picked that same particular song to play a fourth time. And of course, you probably have guessed it by now. Rainbow connection is a song from the 1979 film The Muppet Movie, with music and lyrics written by Paul Williams and Kenneth Ascher. The song was first performed by Jim Henson as Kermit the Frog in the film Rainbow Connection. It actually reached number 25 on the Billboard Hot 100 in November 1979, with the song remaining in the top 40 for seven weeks in total. Williams and Ascher received an Academy Award nomination for Best Original Song in the 52nd Academy Awards. For me, it tells a very important story of someone who is continuing to search for that rainbow connection and what that means, and let you never stop searching. So here it is. Rainbow connection. Why are there so many songs about rainbows and what's on the other side? Rainbows are visions, but only illusions and rainbows have nothing to hide. So we've been told. And some chose to believe it. I know they're wrong. Wait and see. Someday we'll find it. The rainbow connection. The lovers, the dreamers and me. Who said that every wish would be heard and answered when wished on the morning star. Somebody thought of that and someone believed it.

Dr. Osterholm: And look what it's done so far. What's so amazing that keeps us stargazing? And what do you think we might see? Someday we'll find it. The rainbow connection. The lovers, the dreamers and me. All of us under its spell. We know it's probably magic. Have you been half asleep? Have you heard voices? I heard them calling my name. Is this the sweet sound that calls the young sailors? The voice might be one and the same. I've heard it said too many times to ignore it. It's something that I'm supposed to be. Someday we'll find it. The rainbow connection. The lovers, the dreamers and me. Rainbow connection Kermit the frog. Well, thank you again for joining us for another podcast. We've covered a lot of material today. I hope that it's helpful. Again, we welcome your feedback. We appreciate your support. And in following up on this song, I hope this is the emotion you take away from this podcast. Surely consider all the other information presented. But when you go to sleep tonight, think about the rainbow connection. That's the important thing. And when you have an opportunity, please, please be kind. Boy, the world needs it right now. The bugs are out there and a lot of other things that make us feel sad. And now's our chance to respond. So be safe and be kind. Thank you so much for joining us. We appreciate you. Thank you.

Chris Dall: Thanks for listening to the latest episode of the Osterholm update. If you enjoy the podcast, please subscribe, rate and review wherever you get your podcasts, and be sure to keep up with the latest infectious disease news by visiting our website CIDRAP. Edu. This podcast is supported in part by you, our listeners. If you would like to donate, please go to CIDRAP.com edu forward slash support. The Osterholm Update is produced by Sydney Redepenning and Elise Holmes. Our researchers are Cory Anderson, Angela Ulrich, Meredith Arpey, Clare Stoddart, and Leah Moat.