Episode 204: Holding the Tools

Chris Dall : Hello and welcome to the Osterholm Update, a podcast about infectious diseases and public health featuring Doctor Michael Osterholm. Dr. 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, Dr. Osterholm draws on over 50 years of experience in infectious disease epidemiology to provide straight talk on the latest infectious disease outbreaks, counter misinformation and disinformation about vaccines, and distill the complex and ever evolving public health threats facing our world. I'm Chris Dall, reporter for CIDRAP news, and I'm your host for these conversations. Welcome back everyone to another episode of the Osterholm Update podcast. If you're a longtime listener of the podcast and I know many of you are, you've certainly noticed a shift in the podcast over the last year or so. Obviously, much of the shift has been driven by the Trump administration's systematic dismantling of federal public health agencies and by Health and Human Services Secretary Robert F. Kennedy, Jr. S attempts to undermine vaccine policy. We've devoted a lot of time to these topics because they are the driving force behind one of the most challenging moments for US public health in decades. Meanwhile, the virus that led us to create this podcast has taken something of a backseat. We continue to update you on COVID trends, of course, and we'll do that for as long as this podcast goes on, because we know that many of you want that information so you can keep yourself and your loved ones protected.

And we know this is especially important for people in high risk groups, but it's clear that for many, COVID 19 is not the threat that it was when the COVID 19 pandemic was declared in early 2020, or when the Omicron surge began in November 2021. New variants don't scare us as much as they used to. COVID has become a virus that we live with for the last two winters. In fact, there's been much more focus on flu, so we thought this might be a good time to take a closer look at what exactly is going on with COVID 19. How many people are being hospitalized with COVID? How many are dying? Does wastewater data give us a full picture of how much COVID is in the community? Could a new variant change our perception of COVID? A deeper dive on COVID will be among the topics we cover on this March 12th episode of The Osterholm Update, episode number 204. We'll also provide an update on flu and RSV activity. Discuss the surge in norovirus cases, answer an ID query about measles cases in Puerto Rico, and bring you an update on the latest in the US measles outbreaks and share some data from a CIDRAP news investigative series on antibiotic prescribing by dentists. And we'll bring you the latest installment of This Week in public health history. But before we get started, as always, we'll begin with Doctor Osterholm's opening comments and dedication.

Dr. Osterholm : Thanks, Chris, and welcome back to the podcast family. Today, that term is going to take on new meaning. I hope you'll stick around to the end of the podcast because I will be sharing something very personal with the podcast family. And when I talk about the podcast family, please understand I am the beneficiary of what is absolutely a most amazing outreach by so many of you who listen to this podcast, have listened to the podcast for many, many episodes and who share with us not just the quote unquote scientific interpretation of what we say, but also what does it mean in terms of our heads and our hearts and where as a podcast family are we going? And so I can't say it enough times in enough ways. Thank you, thank you, thank you. If I were to be asked in all honesty, what is the benefit package of doing this podcast? Do you benefit more from getting the information from me? Do I get more out of being able to communicate with this incredible podcast family? I win hands down every time. I get much, much more. So thank you. And for those of you who may be listening for the first time or only listen to us on occasion, I hope again we're able to provide you with the kind of information that you're looking for. And also just in terms of understanding where we as a CIDRAP podcast team are driving these podcasts forward. Before I talk about our dedication, I want to also share with you the fact that I've heard from many, many of you about the podcast in which we close with the bells.

Dr. Osterholm : And I want to just acknowledge the fact that that has been an unexpected gift of the number of you who listen to the bells at Saint Mary's Basilica here in the Twin Cities several weeks ago, when we in fact, were at the height of the ice surge here in the Twin Cities. And I can't tell you the kind of response we've had from that. People have gone back and they have recorded the bells sound from the actual podcast itself and kept it. So occasionally we can hit a mark like that. And that was a very special one. Now today's dedication also is something near and dear to my heart. Many of you know that I was born and raised in Iowa and came from a very dysfunctional, actually very angry family, and I was saved emotionally and physically by the editor of the newspaper where my father worked. She and her husband co-owned the newspaper and her name is Nana. Many of you have heard me talk about her in the past, and I early on understood the incredible power of having a strong female role model in your life. And I surely have that. And it's never, never left me. Well, today this dedication is all about March being Women's History Month. We want to dedicate this episode to the talented, committed, and dedicated women who have contributed to advancing public health and the medical field at large.

Dr. Osterholm : From Dr. Elizabeth Blackwell, the first woman to earn a medical degree in the US who trained union nurses during the Civil War, to Henrietta Lacks, a young black woman whose cancer cells from the 1950s went on to become one of the most important cell lines in medical research, helping develop both the polio and COVID 19 vaccines. To Dr. Margaret Fishl, a professor at the University of Miami who is one of the first physicians to treat patients with HIV and who continues to be on the front lines of HIV and AIDS. I, of course, want to acknowledge I work with some very incredibly talented, thoughtful and kind women at CIDRAP. That, to me is a gift that I have every day when I go to work and to each and every nurse, doctor, pharmacist, healthcare worker, physician, assistant who has tirelessly worked tending to our most vulnerable communities. You will hear more about one of those historic health care heroes in our public health history segment later. According to the World Health Organization, nearly 80% of the global health and social services workforce are women, and that closely tracks with CIDRAP as well, where more than 75% of our staff are women. Despite their majority in the healthcare workforce, women only hold about 25% of the leadership roles in healthcare. This contributes to pay inequity and limited career advancement compared to men in the same field.

Dr. Osterholm : And we mustn't forget these discrepancies are only further exacerbated for the women of color. It's critical that we advocate for more equitable pay, opportunities and working conditions for all women this month and every month. Now let me move on to one of the best times of all the year for me. Today in Minneapolis Saint Paul, we have reached the maximum amount of additional sunlight per day at any time of the year. Today, the sun will rise in Minneapolis at 7:30 a.m. it'll set at 7:15 p.m. that's 11 hours, 44 minutes and 28 seconds of sunlight. But notably, we increased our sunlight by three minutes and nine seconds over yesterday. That will continue every day, adding three minutes and nine seconds of sunlight until March 25th. Then we'll keep adding sunlight, but that number will drop and drop to the point when we get to June 21st, then we will see right where we're at the border of losing sunlight. So this is truly a wonderful day for me when we can hit that maximum new sunlight. Love it. To our dearest friends in Auckland, New Zealand, and particularly at the Accidental Belgian Beer House on Vulcan Lane, today your sun rises at 7:16 am. Your sun sets at 7:44 p.m. that's 12 hours, 28 minutes and 35 seconds of sunlight. You're rapidly losing sunlight. However, today you lost two minutes and 22 seconds, and very shortly you unfortunately will break even where your days will actually begin growing shorter.

Chris Dall : So, Mike, we usually don't get to this part of the podcast until about 30 minutes in because we're mostly covering the latest political developments. But today we're going to start with a respiratory virus update. So as we inch closer to the end of winter here in North America, What are we seeing with COVID, flu and RSV?

Dr. Osterholm : Well Chris, there's a lot of confusion right now about which of those respiratory transmitted viruses must we be most concerned? Now, let me just point out we still have concerns about all three. But one of the things that's becoming very clear to me is that, as I have said many times, COVID is not a seasonal virus at this point. You can call it that if you want, but it's only because it occurs in every season. We don't have the traditional winter time flu season like picture with COVID. And today, let me try to share the combination of what we should be thinking about with COVID, flu and RSV. Let's start with flu, where activity does remain elevated. But as I had anticipated during our last episode, we're finally starting to see the signs of declining activity across the board. Remember, we don't declare the end of flu season until outpatient visits for influenza like illness are below 3.1% of all visits. This past week, 3.9% of visits were for influenza like illness, down from 4.5 during our last episode. I think this was a milestone move. I'll add that outpatient influenza like visits decrease in every age group, as did emergency department visits, resulting in a flu diagnosis. These are very positive signs. But let me be clear they don't mean we're completely in the clear. As we've discussed, influenza A typically drives activity in early parts of the flu season. And it did that this year.

Dr. Osterholm : While influenza B activity picks up towards the end of the season. This season is proving to be of no exception to this trend, with influenza B now accounting for 64% of samples at clinical laboratories and 30% at public health laboratories in the past week. While influenza B tends to cause more severe disease and kids. I'm hopeful we can continue to see activity decline and this flu season end quickly, but we're not quite there yet. And just to remind people of the toll that influenza virus can take on kids in particular. If you look back at the 2024 2025 flu season, remember overlapping late 2024 into the winter of 2025, 293 children in this country died from flu 293. Now, this year, we actually see a lower number of cases. But again, remember the season's not over. So far in the 2025 2026 flu season, there have been 90 deaths, well below the 293 of last year. However, even last year, if for the same week of the flu season, we were at 114 deaths. So to get to that 293, there was a lot of deaths that occurred in the period from where we're at right now, i.e. March, until we finally got to the early summer season. So where do I think that the number of deaths will fall? I'm not sure, but I know it will be far below that of 2024 or 2025. But nonetheless, deaths and kids are always a tragedy when we have a vaccine that can make such a difference.

Dr. Osterholm : When you examine the data among children who have died this year, virtually almost all were not vaccinated. Now, on the COVID front, activities decreasing across the board. The national wastewater concentration is low down from the moderate during our last episode, and concentrations are decreasing in every region aside from the West, which is considered very low. Hospitalizations and ED visits for COVID are decreasing across every age group. It's hard to know if activity is going widely undetected because people are not testing or reporting, or if the activity truly is lower. I think in fact, it it is lower based on the wastewater data where we are not dependent on someone reporting an infection. But we'll dive deeper into the COVID trends later in the episode, so please stay tuned for that. I do want to remind you, though, even before we talk about COVID trends, that when we're trying to compare the impact of COVID, particularly in deaths in children with that of influenza, it's remarkable in 2024 for the entire year, rather than a flu season overlapping two years, but in an otherwise equivalent period of time. There were 238 COVID deaths in kids. Remember. That compares to 293 flu deaths in kids. Not a lot of difference there. And that was again with a very severe year for flu. If you look at 2025 so far for cases reported and we know there will be more.

Dr. Osterholm : There was 121 COVID deaths reported in kids. Remember I mentioned earlier that we have 90 deaths reported to date in the 2025 2026 season. COVID extracts a very similar painful number of deaths in kids as it does the flu deaths. I hope that people hear this because when I hear the Department of Health and Human Services continue to say, kids do not need a COVID vaccine, that is just simply not true. We could, I believe, prevent many of these deaths that have occurred if these children had been vaccinated. So this is an important point to make. And as we talk more about COVID in a moment, I'll come back to the fact why these vaccines are so very, very important. Now lastly, let me just cover the RSV activity as that continues to increase. The national wastewater concentration is moderate and rising in every region except the West. Test positivity is also increasing. Emergency department visits and hospitalizations for RSV remain elevated in children under one and 1 to 4 years of age. Though both age groups experience declines over the past week, RSV hospitalizations are slightly elevated in adults 65 and older, but they also experienced a slight decrease over the past week. This is a later RSV season that we typically expect, but that just goes to show we can never truly predict respiratory virus seasons. Stay tuned.

Chris Dall : That brings us to the focus of this episode of the podcast. And Mike, this is timely because tomorrow, March 13th, is six years to the day that the US national emergency over COVID 19 was declared. So we just gave you some information on current COVID activity. But Mike, let's step back and take a big picture look at where we are with this virus. The CDC last month published some data on US hospitalizations and deaths from COVID from July 2024 through June 2025. You just talked about COVID deaths in children. What do the CDC data tell us about COVID's continuing ability to cause severe illness and death in adults, and has that all changed in recent years in comparison to where we were at the beginning of the pandemic?

Dr. Osterholm : Well, Chris, one of the things I think that's really important to begin this discussion with is the idea that the COVID coronavirus is not the same as the influenza virus in many important ways. And I'll come back to that in a moment. But let me just say the questions you're asking here, Chris, are really, really important. And part of the reason I say that is because as we move further out from the acute pandemic phase of COVID, it becomes easier and easier to lose track of where things stand with the virus, especially as it relates to the big picture. On the note, as you mentioned, a team of researchers at CDC published a study in the Morbidity Mortality Report, looking at the estimated number of COVID hospitalizations and deaths across the US from July 2024 through June 2025. I do believe that this particular report is scientifically valid and was not altered by the political leadership of the CDC. According to the estimates we just talked about, there were roughly 290,000 to 450,000 hospitalizations and between 34,000 and 53,000 deaths due to COVID during this period. Now, remember, I also just noted that in 2024, 238 children died from COVID and 20 2025 to date, 121. So you can see most of the deaths obviously were in the higher age groups. When you look at the number of deaths in kids, we don't expect to see kids die. They shouldn't die. And so these deaths from COVID are in themselves truly preventable against the nightmares that they cause. Now, let me just add a quick footnote to these numbers, because I think it's important to understand where they came from. Clearly, testing and reporting practices in this country have changed a lot since the earliest days of the pandemic.

Dr. Osterholm : Because of that, the CDC can't simply count up every infection, hospitalization, or death directly to get the national totals. Instead, they use statistical models to estimate the burden of disease based on the data that is available through various studies, surveillance systems, healthcare networks, etc. so there is some uncertainty when it comes to these numbers, and that's really why there is an entire range. Nonetheless, let me validate the fact that the methods they are using are scientifically valid. That being said, even with that uncertainty, I think the overall picture is fairly clear. On the one hand, it shows that COVID is still capable of causing severe disease, hospitalizations and deaths in this country. But at the same time, these numbers indicate that the burdens of severe outcomes associated with COVID have continually declined over the past several years. For example, in a separate publication, the same group estimated that COVID caused 900,000 to 1.4 million hospitalizations and 73,600 to 132,500 deaths in the US from October 2022 to September 2023. So basically double the numbers we're talking about in these latest estimates. I think it's important not to overlook these numbers. We're still talking about a virus that can hospitalize hundreds of thousands of people in this country and cause tens of thousands of deaths each year. So it really remains an important public health challenge. And that's especially true for those at higher risk, particularly older individuals over 65 years of age, but also for infants less than six months of age and people with underlying health conditions. Each of these individuals with these conditions continue to have the highest rates of hospitalization and severe outcomes.

Chris Dall : So then, Mike, going forward, do you think we'll see a pattern similar to flu, where there are some years that are worse than others based on the circulating strains and how well they match with the vaccines?

Dr. Osterholm : Well, Chris, this is where things get very interesting, if not confusing. Will in fact COVID follow a pattern similar to that of influenza, where some years are worse than others, depending on circulating strains and how well available vaccines match. To me, this is where I see some really important differences between the two viruses with influenza seasonal and fits a predictable pattern. Sars-cov-2, on the other hand, continues to circulate year round, and we've basically seen waves of activity during the summer months when the influenza activity is basically nonexistent. So I'd still push back on the idea that COVID is a seasonal virus that follows a predictable pattern. Maybe that'll change. Who knows? Personally, I still believe one of the biggest wild cards with all of this is the virus's evolution and what capacity it has to change. Earlier in the pandemic, we saw these major changes in the virus. First we had the ancestral virus. Then soon after that came the alpha, then the delta and the Omicron. These were very significant changes in the virus as it was adapting to transmission in humans. And this is similar to what happened in 2009 with H1n1 influenza, where it basically had to come to some kind of equilibrium evolutionarily with human. And it kept changing. If you look at the strain that first emerged in the spring of 2009 versus what we saw in the winter of 2009 and ten, they were very, very different viruses.

Dr. Osterholm : The same thing has happened with COVID. If we look now today as SARS-CoV-2, it is changing very little. We're not seeing these big jumps in the evolutionary changes in the virus. And I think until that happens, we're going to see a pretty similar pattern for COVID over the years to come, with year round transmission potentially enhanced transmission in a winter season just because of the humidity and temperature impact on respiratory virus transmission. But in a sense, I don't see any kind of variant emergence right now that is suddenly going to change this virus in a big way, but it could happen tomorrow. It's just not here now. And so for the past several years now, basically all the circulating COVID viruses we've seen have been the remnants of the Omicron lineage with no major curveball thrown at us. And some of those initial sublineages like the Ba1, the Ba2, the Ba4, Ba5, etc. if those start to happen again, we could see a reemergence of the COVID virus challenge. Remember, we know that the immunity from actual infection and from the vaccines wanes over time. We could see a period several years down the road where more and more of us who have previously been vaccinated or had COVID are not protected against a new strain that might emerge.

Dr. Osterholm : So we're going to have to stay tuned on that. Meanwhile, influenza, I think we're going to continue to see it act like an influenza virus has acted for many, many, many years. And until we have a major evolutionary change in the virus, like we saw in 2009 or in 1918 or 1957, those changes were very different in a way that meant we were not protected against that virus. We had not encountered it before and had no immunologic memory. Unless that happens, we will continue to see rather the seasonal changes where we go from an H3n2 of one type to another H3n2 of another type, but not going from an H3n2 to an H5n2 for example. That would be the difference. So stay tuned. I think flu is going to continue to cause us great harm. And I think COVID is going to continue to cause us great harm. Our job is to minimize that harm as much as possible. And what that means is that, in fact, vaccination remains by far the most important tool. We have to take that on. So I would urge you to get your annual COVID shot and a booster and an additional dose, if in fact, you are at an increased risk for serious illness. And clearly, each season gets your flu shot.

Chris Dall : Mike, we're also seeing an uptick in norovirus cases that began in late December of last year. Is this the typical pattern that we see with norovirus or is something different going on?

Dr. Osterholm : Well, let me first of all say that many of us in this business of infectious disease epidemiology have had to wrestle with certain infectious diseases over the course of our career. I can honestly say that some of my very earliest work, before we even knew what a norovirus was, occurred with this virus. So I've had more than 50 years of arm wrestling with this virus, and I unfortunately have been on the bad side of its infection status sometimes, too. Any of us listening to this podcast today can attest to the fact a norovirus infection is nasty. It is not something any of us want to experience. Last season, norovirus outbreaks did reach decades high levels. For example, from August 2024 to early February 2025, the CDC's Neurostat network, which monitors norovirus activity in 14 states, reported 1707 outbreaks, not 1700 cases, but outbreaks. However, outbreaks normalized during the same period this year at 644, placing the season within the middle 50% of outbreaks from the same period during 2012 to 2025. Norovirus wastewater levels are still moderate to high across the country, but have been declining over the past three weeks. Now, it's important to understand a little bit about what we know about the virus itself and how it changes as much as we just had the discussion about COVID and influenza, and it turns out the original norovirus that was first isolated and identified goes by G1, and now we're into a G2 status with the Noroviruses.

Dr. Osterholm : And even within G2, we have a whole series of numbers. And right now we're in G2 17 with some cases occurring from G2 14. So the virus itself can change and does change. And that's important because our waning immunity like we see with COVID is very real with norovirus within 6 to 12 months. Any immunity you may have had from a previous infection wears off, and the immunity from a G2 17 versus, say, for example, G2 four virus may mean that you don't have protection from one norovirus infection to another. So this makes it fairly complicated in many, many ways. While we can't be sure what causes this outbreak fluctuation, it likely has something to do with the G2 17 norovirus strain, which emerged in Asia a decade ago. Many Americans do not have immunity to G2 17, which caused 75% of US norovirus outbreaks last season, and that is up from 10% in 2023, but now down again in this year of 24%, which again could account for why we're seeing the case numbers drop. So the bottom line message here you want to understand is that there is some very important evolutionary issues that are occurring with these noroviruses. And if you get caught with waning immunity and with one of these new strains, good luck, you may be in trouble. On the other hand, if you have had an infection with a specific norovirus strain recently, you may very well be protected if you encounter it again.

Dr. Osterholm : Time will tell as we better understand the immunology of this virus. Let me note that this is a highly contagious virus, and that it's one of the leading causes of vomiting and diarrhea from infection related inflammation of the stomach and intestines. Most cases resolve on their own, but it can be deadly, especially among older adults. While norovirus outbreaks can occur at any time of the year, they are most common in the cooler months when people gather indoors. Norovirus was spread through both direct physical contact or contaminated food or water often makes the news for causing outbreaks on cruise ships, but it also often affects hospitals, restaurants, nursing homes, schools and child care facilities. Contaminated raw oysters, leafy greens and fresh fruits are common foodborne sources of norovirus, and we know from our own studies that the Minnesota Department of Health that, in fact, aerosolized vomit can also be a very important source of virus. In terms of transmission, I can remember very well an outbreak that we worked up in a Minneapolis suburb at a school that was basically one large room with six grades, all in different pods but no walls. And the kindergarten children in a separate part of the building on a different ventilation system. And at that particular school, one day a child vomited at a certain location in this area with all these different classes.

Dr. Osterholm : The janitors immediately went to work on the carpet where the vomit was and scrubbed it up and used a brush to basically brush it out. Well, unfortunately, two days later, over 60% of the school was out with norovirus. When we actually plotted out the location of where the vomitus occurred and the location of the open room classroom for a given class, there was a perfect correlation between the distance from where the janitor had scrubbed the rug and where the people actually got infected. So this is another important area. We do hear some people talking about fomites with norovirus. This seems to be a popular comment from the CDC. Our own experience is that Fomites probably play very, very little role in transmission. And it really is largely about consumption of contaminated food or being in very close contact with someone and actually aerosolizing the virus that way. Due to the challenges of developing vaccines against this highly diverse group of noroviruses, there are currently no approved vaccines, but development and testing continued. In the meantime, you can protect yourself from norovirus by heating food to adequate temperature. Washing fruits and vegetables before eating. Washing clothes in hot water and washing hands frequently with soap and water rather than hand sanitizers, which doesn't work necessarily all that well against norovirus.

Chris Dall : Mike, I'm going to return here to flu for a minute because two weeks ago, the World Health Organization announced the viral strains that will be used to update next season's flu vaccines for the northern hemisphere. This is a process that happens every year, but this year was a bit different, with the US having left the W.H.O. today. The FDA's Vaccine and Related Biological Products Advisory Committee is meeting to discuss the W.H.O. recommendations. Mike, given the chaos we've seen at the FDA this year, do you have any concerns about how this process is going to play out?

Dr. Osterholm : Well, Chris, without sounding like I'm trying to be smart. Yeah, I have a lot of concerns. I can't even imagine what might happen. In short, it's just tough to say how anything will play out with this administration. Chris. They don't follow the usual playbook, but I'd be surprised if they came to a different conclusion than the W.H.O.. Typically, the W.H.O. makes the strain recommendations based on samples collected from independent labs across the country. Then countries are responsible for deciding if they agree with the W.H.O. recommendation and subsequently producing their own vaccines in the US. The decision of whether or not to agree with the recommendation falls in the hands of the FDA. Historically, the FDA has agreed with W.H.O. recommendations, but today's meeting you mentioned will be very telling, not only for the strain selection process, but also for manufacturing. Let me remind you that just last month, the FDA refused to even consider Moderna's application for their mRNA flu vaccine, claiming that the clinical trials did not include the appropriate standard of care comparator in the control arm, despite FDA approving the trial design prior to enrollment. As you all know, the FDA later backtracked and agreed to review the application. But this raises major questions about the FDA's actions and their attempts to create new barriers for vaccine manufacturers, particularly if it involves an mRNA vaccine.

Dr. Osterholm : Needless to say, we'll be watching the Vrbpac meeting closely. The W.H.O. recommended that next season's flu virus include the H3n2 subclade K that has been circulating this flu season, which comes as no surprise. Remember, this subclade was identified last year near the end of the Southern Hemisphere season, but after strain selection for our current season had been made, meaning it was too late to include it in our current vaccines. Because vaccine manufacturers need six months to produce these vaccines. It's also too late to adjust the current vaccines for the southern hemisphere. Despite this mismatch, these vaccines still reduce the risk of medically attended H3n2 by 40% in vaccinated individuals compared to unvaccinated individuals. Again, all the reason why I get my flu shot. The W.H.O. recommendation also includes updates to the H1n1 strain and the influenza B strain, with these specific updates being based on samples from Pennsylvania and Missouri. This might be surprising considering the US lack of involvement of the W.H.O., but again, it is typical for the strain selection process to rely on samples from independent laboratories across the world. Today's meeting will be very telling, and we can only hope that it resembles the strange selection meetings that have occurred in the past. But I'm far from confident that will actually be the case.

Chris Dall : That brings us to this week's ID query. This week we heard from Kristen, the mother of a three month old who's traveling to Puerto Rico in April and wanted to know if we had any information on measles cases and the MMR vaccination rate in Puerto Rico. Mike, what can we tell her?

Dr. Osterholm : Well, first of all, thank you for your question, Kirsten. It can be really difficult to navigate travel decisions when you have an infant who is too young for routine vaccinations. I'm afraid I don't have a clear yes or no about whether travel is appropriate for your family. This conversation is best to have with your child's healthcare provider. However, I can share what we know about measles in Puerto Rico. For the first time in a while on this podcast, we have some positive measles news. The last measles case confirmed in Puerto Rico was in 2019. This was a single imported case that did not lead to ongoing transmission. So that's the good news. No evidence of active measles transmission on the island. Now, Christian, that doesn't necessarily mean you wouldn't encounter measles or any other infectious disease while traveling in airports and other common areas. But certainly for those on the island, it's a sigh of relief. Unfortunately, the good news stops there. The Pan American Health Organization, or Paho, which is the regional office for the World Health Organization in the Americas, is facing a much larger challenge. In a report released last month, Paho noted ongoing outbreaks in 13 countries in 2025 alone. The region had almost 15,000 reported cases of measles. 95% of those cases were reported in Mexico, Canada and the US. Because of this surge, Paho has called on countries in the region to meet and review the status of measles elimination in the Americas.

Dr. Osterholm : The meeting was originally planned for this April, but the US had requested the panel to delay until November, when the November date was noted. There was a lot of pushback from the public health community suggesting this was a political decision, that, in fact, they wanted to not have this negative information come out just before the midterm elections. I've actually had an opportunity to talk to several of the leaders in viral disease, CDC, people who I have great respect for and have been there for many years who said no. In fact, the complexity of the investigations right now of tracing down all the measles strains genetically sequencing them and evaluating them does mean that they need this much time. So I, for one, am willing to acknowledge the conspiracy theory doesn't hold here that in fact, according to the real experts who were not influenced by a political leadership decision, said, we need this much time because of the complexity of what's happening with transmission, outbreak evaluations and so forth. So Kristenl Puerto Rico currently appears to be measles free. A regional resurgence in the Americas and major pockets of Under-vaccination globally are important reminders that the United States is increasingly part of the global measles problem, not just a country worrying about imported cases from outside our borders.

Chris Dall : So, Mike, the measles picture in Puerto Rico looks okay, but that's not the case with the rest of the United States. What are the latest numbers on the US measles outbreak?

Dr. Osterholm : Unfortunately, Chris, the measles situation in the US keeps getting worse. This is not a surprise. According to the latest CDC update on March 5th, there are 1281 confirmed cases in the US across 31 jurisdictions. And this is just for 2026. Putting that into context, at the same time, last year, March 2025, we had around 200 confirmed cases of case of measles. So again we're comparing 1281 versus 200 at the very similar times of the year. So we're really off to a rough start. And there are no signs of things slowing down. As I mentioned in our last question on the Paho update, the US, Canada and Mexico have all experienced substantial recent waves of measles cases. We've mentioned Canada on this podcast before as a potential harbinger of things to come. After a record year of more than 5000 cases in 2025 and the loss of their measles elimination status, Canada actually has fewer cases of measles compared to the US right now. Approximately 320 compared to our 1300. Now, I might note that also again, remember Canada has a substantially much smaller population than we do 40 million versus our 340 million. Mexico is another close neighbor that we haven't discussed in much depth in recent podcasts. They also experienced record highs in measles last year, more than 9000 cases in 28 deaths.

Dr. Osterholm : If we were to do the math again, the US population is approximately two and a half times the size of Mexico. So if we were to follow the same trajectory from last year, that would be the equivalent of 22,500 cases in the US. Similarly, with the same analysis for Canada suggest over 40,000 cases in the US. If we were to follow their path. So just to summarize, per capita, Canada and Mexico has experienced the steepest relative increases in the Americas. But I think the lesson to be learned is very clear. North America is in big trouble when it comes to measles, and the US is a sitting duck for this situation now. The surge is a reality check on why vaccination matters. Those small pockets of undervaccination really add up over time, leaving communities vulnerable. It's especially frustrating because we have such a highly effective vaccine. We are holding the tools to stop further harm and halt the spread of a really nasty virus. I can only hope that as people witness the severity and devastation measles can cause, it sparks a collective wake up call across the public to take action and protect our communities once again.

Chris Dall : Mike, what is the latest from CIDRAP vaccine Integrity project?

Dr. Osterholm : Well, Chris, let me just start out by saying it has been a true gift in my career to be able to be part of this operation and what we're doing and to see the many, many very talented, committed individuals who are investing into this effort. We are making up for the major deficit that our government has put us in in terms of vaccine recommendations and use. Our team has been hard at work on this effort, including many of our incredible podcast team members who you all never hear their names, but you benefit from them every time you're on this podcast. And let me just say, I so appreciate their dedication to gathering, reviewing, analyzing, and sharing the best information we have on vaccines. Clinicians, policymakers, and the public all depend on the information they can trust. And that's exactly what the Vaccine Integrity Project seeks to provide. As we covered in our last episode, an evidence review is currently underway on the human papillomavirus, or HPV vaccine. We anticipate that the HPV vaccine may be a topic of discussion at future ACip meetings. So that work is moving forward quickly. We also announced last episode that we have kicked off our 2026 2027 Respiratory Virus Immunization Evidence Review in collaboration with the American Medical Association. This review will include COVID 19, RSV and flu immunizations. Evaluating the latest evidence on the safety and effectiveness of vaccines. A new initiative we have recently announced is a focus on vaccine safety and effectiveness in pregnancy. After the addition of two obstetricians gynecologists to the ACip who have expressed concerning views on vaccines, the Vaccine Integrity Project announced another independent review of a critical vaccine given in pregnancy, namely that of Tdap.

Dr. Osterholm : The Tdap vaccine protects against tetanus, diphtheria and pertussis, and is especially important in providing infant protection against whooping cough in the first months of life, prior to when they are eligible for a vaccination themselves. The recommendation for maternal Tdap was established 25 years ago and has been highly effective in protecting vulnerable infants around the world. Our independent review will examine relevant literature on the safety and effectiveness of this vaccine during pregnancy to equip clinicians, our partners and the public with the best available science, regardless of future ACip discussion. While Tdap has not received nearly as much political attention compared to COVID 19 and mRNA vaccines by this administration, it does contain aluminum based adjuvant, which have been criticized by some ACip members and the broader Maha movement. Rest assured, the Vaccine Integrity Project will always put science rather than politics first in these discussions, and it's worth noting that pregnancy will also be a population of interest in our respiratory vaccine review this summer as well. Beyond evidence reviews, our team is also working in other forms of public communications to respond rapidly to the growing misinformation and chaotic public health actions emerging from the current administration. Our latest viewpoint article, written by VIP staff and advisors, highlights the importance of Gavi, the Vaccine Alliance. This organization is one of the most prolific initiatives for expanding access to vaccines globally, especially to young children in lower income countries.

Dr. Osterholm : The US has been a longtime supporter of this work until Secretary Kennedy pulled funding last year. We will link the viewpoint article in our show notes so you can learn more about the impact of this decision and the millions of lives that are at risk. I'll close by saying how impressed I continue to be with this team and the many partners we work alongside. That includes medical societies, state and local public health organizations, and the general medical, nursing and pharmacy communities throughout the country. Thank you to all of you for all that you do to help make this possible. Even in the challenging times we find ourselves in for vaccines and public health, there are fierce advocates ready to ensure these tools remain available to everyone who needs them. Chris. Now I have the opportunity to kind of flip the switch here and to introduce you to actually cover a very important topic area that we've addressed recently at CIDRAP news. I want to just compliment you for your long history of providing outstanding reporting on issues around antimicrobial resistance and the issue of antibiotic stewardship. I'll let you explain more about what has happened here. But for all the listeners, I'm telling you, this is a landmark effort that was just completed at CIDRAP, and we're very, very proud of it. So, Chris, I'll turn it over to you in terms of the antibiotic aftershock series.

Chris Dall : So yeah, Mike, I wanted to take a minute here to talk about our new investigative series by CIDRAP news reporter Liz Szabo called Antibiotic Aftershocks. I mentioned it on our last podcast. If you haven't had a chance to read the series, I encourage you to do so. In her reporting for this series, Liz obtained data showing that US dentists wrote 27 million antibiotic prescriptions in 2025, a 6% increase from 2020. In many cases, these prescriptions are written to prevent a potential bacterial infection after a dental procedure. And while prescribing preventive antibiotics is appropriate for patients with certain medical conditions, research has shown that up to 80% of these types of prescriptions are not necessary, and this is important for two reasons, Mike. For one, we don't want to overuse antibiotics because that promotes antibiotic resistance and makes these drugs less effective when they are actually needed. Secondly, antibiotics have side effects. Lizzy's series, in fact, kicks off with the story of Dolores. Hernandez owns a 92 year old woman who developed a deadly infection caused by Clostridioides difficile, a bacterium that causes severe diarrhea. She developed this infection after taking the antibiotic clindamycin following a tooth extraction. Now, clindamycin has long been known to pose an especially high risk for C diff infections, and while it's used by dentists as declined, there were still 2.3 million prescriptions written by dentists in 2025. So Mike, this series, which also examines the reasons why dentists write so many unnecessary antibiotic prescriptions and what you can do to avoid unnecessary dental antibiotics, is another reminder that inappropriate antibiotic use and antibiotic resistance are ongoing public health issues that will threaten all of us if they are not addressed.

Dr. Osterholm : And thank you, Chris, for sharing that information with us. And I want to compliment Liz on what was simply an outstanding effort to pull this information all together. As you laid out, Chris, these challenges are immense. And every day that we continue to inappropriately use antibiotics, we just end up favoring the development of resistance from these organisms. And I don't think most people have any idea of what the potential risk is for some of these infections, based on the fact that they acquire a resistant strain due to taking an antibiotic that they never needed to take to begin with. So thank you to you and the news team and Liz in particular for your outstanding work.

Chris Dall : That brings us to this week in public health history. Mike, what are we celebrating this week?

Dr. Osterholm : Well, to kick off Women's History Month, which I mentioned in the dedication, I want to highlight Jane Delano, a founder of the American Red Cross Nursing Service. Jane was born on this day, March 12th, back in 1862. She studied nursing in New York City before moving to Jacksonville, Florida, to become a superintendent of nurses at a local hospital. During Jane's time in Florida, there was a yellow fever epidemic. She installed window screens and mosquito netting in patient's room and in nurses quarters. This was truly innovative because scientists had not yet confirmed that mosquitoes carried the disease. Jane continued to work all over the country, supervising and training nurses from coast to coast. She was determined to uplift the nursing community, especially at a time when nurses weren't fully recognized as valuable members of the medical profession. By 1912, Jane had multiple leadership roles in the nursing world. She was the superintendent of the Army Nurse Corps, president of the American Nurses Association, the chairman of the Board of Directors of the American Journal of Nursing, and the chairman of the new National Committee on Red Cross Nursing Services.

Dr. Osterholm : Wow, what a lineup of efforts. Jane organized a Red cross nursing service as the official reserve for the Army, Navy and Public Health Service. She is credited with helping register more than 8000 nurses in the Red cross. By the time the U.S. entered World War 1 in 1917, by Armistice Day in November 1918, there were over 20,000 Red cross nurses who had volunteered both at home and abroad during World War One. Jane's work took her all over the world. In 1919, she traveled to France to visit some of the nurses she had helped recruit for the war effort. There, Jane became sick and needed surgery. Unfortunately, her condition did not improve and she died at April 15th, 1919, at the age of 57. It's reported that her last words were, what about my work? I must get back to my work. So today, on Jane's birthday, we honor the life and legacy of a true hero, Jane Delano. Thank you, Jane, for your tremendous dedication to nursing and for all the good that you brought so many people.

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

Dr. Osterholm : Well, you know, come on, audience, you got to admit, I gotta say something about of the three take home messages, what sunlight means. So my first take home today is here we are in Minneapolis, three minutes and nine seconds of additional sunlight than yesterday, but three minutes and nine seconds less than it'll be tomorrow. So this is a big, big day for us and we celebrate it. My second point is, is that clearly the winter respiratory season is on the wane. I think that within the next 3 to 4 weeks, we will continue to see the numbers of infections from COVID, influenza and RSV continue to drop. And that's obviously good news. And the third message is measles, measles, measles, measles. We're going to have an academic diet filled with truly devastating stories of measles in the months ahead. It's so unfortunate. So unnecessary. Yet it's going to occur. So sunlight respiratory season and measles I think are the three take homes today.

Chris Dall : And what is your closing for today?

Dr. Osterholm : Well, Chris, this is probably going to be one of the most unusual closings I've ever had in the 200 plus editions of this podcast. It's going to come in two different tranches. First, marking Women's History Month in the dedication and the public health history segment really does not do justice to the contributions that women have made to so many areas of public health and the kind of issues that we deal with. So today, I also want to highlight one additional woman who I've actually highlighted in the past, and it's one that I believe is a hero of heroes for her perseverance. For her contributions to medicine and her overall approach to saving the lives of so many people. I'm talking about Madame Marie Curie. Marie Curie was born in Poland in 1867. She lived until 1934. In 1903, Marie Curie was the first to work towards developing the many possible benefits that humankind may extract from radioactivity while minimizing its enormous risk. More than a century later, the struggle still continues. Marie Curie was a two time winner of the Nobel Prize, won in 1903 for physics, won in 1911 for chemistry. She also had a life story impacted significantly by infectious diseases. Her mother developed TB shortly after her birth and 11 years later died from TB.

Dr. Osterholm : In addition, her older sister died from typhus. I could quote many, many statements from Madame Curie that would help demonstrate the true person she was and the significance she brought to her work and to the world. But let me just leave you with one. I think it's one that fits the time. Nothing in life is to be feared. It is only to be understood. Now is the time to understand, more so that we may fear less. Such wise, thoughtful words. Now the second part of my closing. This may surprise some of you that I do this, but you're part of the family, you know, and family needs to share things sometimes. I want to also, in keeping the notion of leadership and women, I had the good fortune. The miracle, you might say, on Friday night, February 27th, of marrying the dream person of my life, someone who brings such great strength, brings great common sense, dedication, and is just all around the best person I've ever known. Fern Peterson and I got married. It was a wedding, was a beautiful event with our kids and grandkids there, and I am the luckiest man in the world. So from a family standpoint, you got to know we've officially added someone in, although she has a podcast listener, so I guess we had her already captured that way.

Dr. Osterholm : But Fern, thank you, thank you, thank you. You make life for me a gift. And in that light, I hope all of you find a way in the next two weeks before our next podcast to find a way to also provide gifts to those in your life, and to remember that at this crazy, crazy time when there are so many things that are upsetting, concerning, frankly, very difficult, how do we get through? We get through with kindness. We get through by trying to do the right thing to help. And so I hope that all of you are able to find a way in the next two weeks to just one kind thing, just one kind thing, and understand the impact that that will have. It's like a riffle of a rock being thrown into a pond. Watch the riffle. So anyway, thank you so much for joining us. I hope that we're able to provide you with the information you're looking for. And I look forward to being back with you in two weeks. In the meantime, be kind. Be safe. Thank you.

Chris Dall : Thanks for listening to the latest episode of the Osterholm update. If you enjoyed 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. The Osterholm update is produced by Sidney Redeppening Elise Holmes and Ruby Guthrie. Our researchers are Cory Anderson, Meredith Arpey Leah Moat, Emily Smith, Clare Stoddard, Angela Ulrich, and Mary VanBeusekom.