In this episode of A Moment in Health, Dr. Ashish Jha highlights a striking new statistic: 40% of fully subsidized ACA enrollees had no insurance claims last year — a number far higher than the 15–20% typically seen in employer-based plans. He then reviews a major New England Journal of Medicine trial showing that a modified mRNA influenza vaccine reduced lab-confirmed flu infections by 35% compared to traditional flu shots, producing stronger immune responses with slightly more short-term reactogenicity. Associate Professor of the Practice Dr. Craig Spencer, emergency physician and public health leader, joins to discuss his experience attending the Children's Health Defense conference in Austin — unpacking the movement’s growing cohesion, the small but vocal anti-vaccine contingent, and why many attendees feel unheard by the health system.

Dr. Jha discusses:

• Efficacy, Immunogenicity, and Safety of Modified mRNA Influenza Vaccine — New England Journal of Medicine
• I’m a physician who went to the anti-vaccine movement’s biggest gathering. More of my colleagues should too — STAT

About the Guest

Dr. Craig Spencer is an emergency medicine physician and an Associate Professor of the Practice of Health Services, Policy and Practice at Brown University School of Public Health. As a physician he focuses on frontline preparedness, both in the U.S. and globally, especially on the impact of COVID-19 on health systems. This includes the real world impact of pandemic preparedness – or lack of preparedness – for clinicians and patients, particularly from a humanitarian perspective.

About the Host

Dr. Ashish K. Jha is the dean of the Brown University School of Public Health.

Music by Katherine Beggs, additional music by Lulu West and Maya Polsky

Hey everybody. Ashish Jha here from Providence, Rhode Island, coming at you with another dose, another episode of moment in health, the podcast where you talk about one data point, discuss a study and answer a question, and let's jump into the data point. And the data point this week is a little controversial, but I'm going to go ahead and going to go ahead and say it. It's 40% 40% according to the Paragon Institute, 40% is the proportion of fully subsidized ACA enrollees who did not have any claims in the last year. Now, why is that number interesting, and why is it controversial? Well, it's interesting and controversial because the Paragon Institute, Brian Blaise, who runs it, has been arguing that there has been massive fraud in the ACA plans, certainly lately, since the enhanced subsidies in the covid era. And when he brought up that number, and members of Congress touted that number, a lot of people went nuts and said, Well, that doesn't really show fraud. 40% of people not using health insurance in a given year. That's no big deal. I mean, 95% of people don't file a claim against their the homeowner's insurance in a given year. Similarly, 95% of auto insurance people don't file a claim against their auto insurance. So that doesn't tell us anything. But here what? Here's why I actually think that number is interesting. If you look at similar plans, employment based plans, in a typical year, about 15 to 20% of people do not file any claims. That's non elderly Americans who get health insurance through their employer. About 15 to 20% don't file claims in a given year at 40% for the ACA fully subsidized plants. That does feel like a pretty high number. And you begin to worry, I do that there are a bunch of people signing up who may not even know that they have health insurance. And if you care about the ACA the way I do, and I actually think the ACA has been, in general, a success, not not a home run, but a success. And I believe that

everybody should have health coverage, then making sure there is not fraud in the system should absolutely be a priority for those of us who believe and care about universal coverage and care about the ACA. So I want to talk about that 40% number, because the bottom line is we need to make sure everybody is covered, but we also need to make sure that we have integrity in the program, and the ACA needs to be a program that actually gets implemented the way it was intended, making sure that people who need subsidies get it and people who don't need subsidies don't.

All right, I want to now move on to the study of the week. And the study of the week comes from the New England Journal of Medicine from November 20, 2025, and it is entitled efficacy, immunogenicity and safety of modified mRNA influenza vaccine. So you all know, having heard me before that, I'm a big believer in the flu vaccine. Actually think the evidence is not just a random belief, the evidence is very, very clear that everybody should get the flu vaccine, and we have multiple ways that we make the flu vaccine, egg based, cell culture based, but a lot of us have been interested in the mRNA technology because it should allow us to design flu vaccines more efficiently, better targeted. But we don't actually know if that is true, and moderna and other companies have been working on mRNA vaccines, and this paper, published in the New England Journal, shows pretty convincingly a couple of things. First of all, a modified mRNA influenza vaccine is at least as good, and actually the stat the study really the data, seems to show that it is better than your traditional flu vaccines in terms of efficacy that is preventing infections from influenza. Now this study looked at about 18,000 people randomized to a traditional flu vaccine versus mRNA, and they found about a 35% reduction in laboratory confirmed influenza vaccine or influenza infections in the people who got the mRNA vaccine, they saw much better and higher levels of immunologic titers. And then when it came to safety, as you might expect, with mRNA vaccines, you tend to get a little bit of what we call sort of reactogenicity. We saw this with the covid vaccine, where in the first 24 hours, you tend to just feel a little bit worse than you do with traditional vaccines. They saw that here as well. No no real signal of anything significant, nothing serious in terms of side effects, but more of that kind of reactogenicity. So what's the bottom line conclusion here? I actually think mRNA vaccines for flu are

going to be a really important part of the of the sort of playbook for how we're going to want to prevent and manage influenza every season. And I think mRNA vaccines, yes, they might have slightly more side effects in that short run, but if, but if you pair that with much greater efficacy, it is going to end up being a winner. So we'll see what happens as these things move forward. Go through the FDA process, but I am looking forward to a future where we have mRNA vaccines for influenza.

All right. And now for the one question of the week, and for this question of the week, I have my friend and colleagues, Craig Spencer. Dr Spencer is an ER physician, widely known for all of his fantastic writing in stat the Atlantic, et cetera, and also a professor here at Brown School Public Health, Craig, thanks for being here. Thanks for having me really excited. So I'm going to talk about that stat piece you wrote a few weeks ago, which I loved. And if you haven't had a chance, you should find it. And it's about the MaHA conference that happened recently that Craig went to. And I loved it. I felt like I learned a lot, but I would love it if you would talk about, why'd you go and what did you learn at this event?

Yeah, it kind of started as a joke, texting with someone that I know that runs a podcast. And I said, Hey, we should go to this. And then she said, Yeah, should we go to this? I was like, Yeah, we should go to this. And so we signed up and we went. And I'll be honest, it was probably the most impactful, most interesting and most educational conference that I've been to, because I learned an incredible amount. One of the big things that I learned me going in, I wanted to understand what part the anti Vax community had as part of Maha, that larger Maha tent, and the understanding that I had going in was that, you know, one wasn't the other wasn't one, but I saw that what you had was this really in bold and really ascendant community of folks. Again, this was started by CHD, started by RFK, Jr, who was no longer at the head, but who was pushing a lot of the agenda on the federal level. And this was a group of people that felt emboldened, and we're taking action, and we're claiming the anti Vax title, right? Like to turn it from a slur or two into a symbol of pride, yeah? And so I learned that. I also learned that this community, the anti Vax community, the community skeptical about vaccinations, is incredibly polished, incredibly strong, incredibly well funded and organized. This was the most organized conference I've ever been to, on the inside, and the outside, things ran on time. But what was fascinating to me was that when I go to conferences, there's always an opportunity to ask a question. There's microphones around the room. There weren't any here. And I thought, Well, does that mean they don't want us to question they're there. They're telling us to question everything. But the reality was, is that there wasn't anything to question. Everyone was it was brought in and bought in, and it was more like a revival or a religious experience, yeah, where everyone felt community. At one point, someone said, I want everyone in

the room who has a family member who is vaccine injured to stand up, and about two thirds, maybe three quarters of the room stood up. Wow. So this is clearly like a biased community in their own experience, but what they're bringing is, is, is a strength and a passion that, frankly, I would love to see more from our side in public health.

Yeah, I think the idea of the community being biased, every community is biased. So there's something that brings people together. Here's a couple of clarifying questions. How much of the MaHA movement is anti vaccine? Is the overlap? Very, very high? Is it medium like, what's your sense? I don't need an exact number, but Maha is much bigger than vaccines, of course, absolutely. And what is your sense of that from attending this event? If I were to guess,

I would say that under the Maja umbrella, probably somewhere between five to 10% of the movement is kind of anti vaccine. Now, I think there's also a difference between the really anti vaccine folks are going to spend money to show up in Austin to listen to del Bigtree and Gavin de Becker say, you know, it could be an anti Vaxxer and, like, get excited about it. I think the majority of folks probably exist in some space in between where they have questions about the Hepatitis B birth dose, or they want vaccines to be offered on a little bit of a different schedule that might be more individually tailored for them or their family. I think that's the majority from this. I've also seen that there's a lot of people in maha that are not anti vaccine at all, that people that have been pushing for the same things that we in public health have been talking about for decades, chronic diseases, environmental issues, concerns about pharmaceutical influence, health care costs, all these things that you've talked about and written about and we've all been concerned about for a long time. I think the difference is, and what is really inspiring the MaHA movement right now, it's giving it more traction, and I think allowing it to grow stronger is the fact that they see RFK Jr, in this movement doing things. And in public health, we will say we've been doing this stuff for we've been looking at these issues for so long. But what they see in RFK Jr, in this administration, is them doing things, even if the things that they're doing they don't necessarily always agree with. They like the fact that they're trying stuff. And I think that is what's uniting all of the people under that big Maha tent, the anti Vax groups, the environmental people, the people concerned about costs, are all concerned and united on one thing, getting things done. Awesome.

One last quick question. This is a Claire, well, I've blown the one question rule already. So what advice do you have to physicians, to public health people about how to engage this group of Americans who feel strongly have community care deeply about health. We care deeply about health. They care deeply about health. What advice do you have for people like me and others in public health?

We need to engage. And I know it's really hard, and having conversations with people that we completely disagree with is not easy. Look, I spent a decade in humanitarian response negotiating access with like, you know, terrorists and you know, people that were like, trying to, like, kill my community or whatever. And so talking to anti vaxxers Doesn't seem like a step too far, yeah, but for a lot of us, it's hard in this moment where it feels like RFK, JR And this administration has destroyed the CDC, destroyed our global standing, has inspired people to shoot hundreds of bullets at the CDC, to feel like we are unsafe and we're under attack. I think that is all true, but I also have seen the majority of the time that I reach out to people that disagree with me, that have been ostracized from medicine, from public health, they have this exterior that seems really hard to crack, and they're hurt, but as soon as you reach out a hand, they'll reach one back, and they'll have a conversation with you. And I have heard dozens of times in the past couple of weeks. This was the first time that someone was willing to treat me like a human in the last five years. I don't think it's going to change anything. I'm not trying to change them. Yeah. What I'm trying to do is I'm trying to understand what we need to do if we want, as a public health community, to wall off the anti vaccine part of this, I think we need to take action on all the other things that Americans have identified as important, health care costs, concerns about pharma, all those other things. Maha went from 0% support because it didn't exist, to somewhere near 50% support, not because of RFK Jr, but because he surfaced a lot of tensions that have been there for a long time. We as a public health community need to recognize that it's not just an immediate knee jerk reaction to everything that comes out of his mouth to say that it's wrong, but to look at the substance engage and rebuild trust

with people, otherwise we risk undermining all of the efforts that we're trying right now to protect our vaccine infrastructure in

particular, awesome Craig, thanks so much for coming by and thanks for the conversation. Thank you. Applause. All right. There you have it. Another episode of a moment in health where we talked about one data point, 40% 40% comes from the Paragon Institute proportion of fully subsidized ACA enrollees who didn't have any claims in the past year, a number that's higher than you'd expect with generally privately insured people at least suggested that there may be some amount of fraud going on in the system, or just people are enrolling who don't even know that they have health insurance. And for those of us who care about the ACA and want to make sure the program has integrity, that is a number worth understanding better. We talked about one study, the efficacy, immunogenicity and safety of modified mRNA influenza vaccines, phase three trial in the US, South Africa and Philippines, 18,000 people, and found that the vaccine was about the mRNA vaccine was about 35% more effective at preventing infections. It was a little bit more reactogenic, as I said, that sort of crumminess you can feel for 12 to 24 hours after an mRNA vaccine. That happen more often with the mRNA than traditional but but significantly higher efficacy. And then, last but not least, we talked to my friend Craig Spencer about his visit, his time in Austin, Texas, at the MaHA conference. I thought that conversation was fascinating. He talked about people there, feeling a strong sense of community, feeling like they're finally being heard. An important point that he made is that we should not ever confuse Maha with anti Vax, that while there are people who are anti vaccine inside the MaHA movement, they're the minority. A lot of people are questioning about vaccines, and a lot of people are there because they feel like they have been treated badly by the healthcare system. And his final point, which I thought was so critical, is all of us have to do a better job of reaching

out, of listening and of understanding what is driving people towards Maha because a fundamental principle of public health is that we don't leave people behind, and if they don't agree with us on some issue or other, we don't decide that they are unworthy of us engaging and doing what we can to help them live healthier, better lives, and we should be absolutely applying that principle to people in the MaHA movement as much as we do for anybody else. So I thought it was a great conversation and a great point. Thanks so much for listening. This week, I'll be back next week with another episode of a moment in health where we'll talk about a data point, discuss a study, answer a question. Have a great week. Folks. You.