Infectious Dose

Infectious Dose

Infectious dose is the shot of science you need to protect yourself from misinformation. Heather McSharry, PhD, an expert in viral pathogenesis, brings her blog to the airwaves to help bridge the dangerous gap between the science of infectious diseases and public misperception. On the podcast website, infectiousdose.com, all episodes have corresponding blog posts with the information contained in the episode along with links or PDFs for all sources used. To prevent unwelcome surprises, episodes with limited, mild profanity are marked as explicit. *Podcast intro and outro music are adapted from Heather Nova’s song, I Miss My Sky. Used with permission.

Episodes

October 1, 2025 34 mins

Step into the shoes of a 1970s CDC outbreak detective as a mysterious cluster of fatal pneumonia cases pulls you into the shadows of a crumbling city hotel. In this immersive Month of the Macabre episode, you’ll chase clues through fog-filled ballrooms and forgotten ventilation shafts, racing to stop an invisible killer before it spreads. Along the way, the case, inspired by a real investigation, reveals just how crucial—and fragil...

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Our public health safety net is unraveling. In this episode, we explore why infectious disease surveillance — once our invisible safety net — is quietly vanishing, and what that means for early outbreak detection. Dr. Jim Alwine breaks down common misunderstandings around gain-of-function research and explains how fear-driven narratives like the lab leak theory have warped public perception and policymaking. We also examine how rec...

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Organizer–sociologist Jon Shaffer, PhD, (Defend Public Health / University of Vermont) joins Heather to talk about turning evidence into local, winnable public-health protections. We dig into why “apolitical” public health backfires, how real teams (not one-off mobilizations) build durable power, and practical, nonpartisan roles for scientists and clinicians—even if you only have an hour a month. Though this moment really deserves ...

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West Nile virus is back in the headlines, with new human cases in the U.S. and steady activity in Europe. In this episode of Infectious Dose, Heather tracks the current outbreak season through CDC and ECDC surveillance and state-level reports, explores how the virus cycles between birds and mosquitoes, and examines what happens when you get infected. Most infections are silent, but for a small fraction, West Nile unleashes a devast...

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This week, Heather pulls back the curtain on how she figures out what’s true. From gut checks and trusted sources to the brutal training of grad school and the constant practice of science writing, she shares the habits that help her navigate conflicting claims—like the current confusion around COVID vaccine access. You don’t need a PhD to think like a scientist, just the right process.

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Heather brings you a bonus mini Booster Dose episode to explain everything you need to know about the new changes in FDA-approved access to fall COVID shots, who’s eligible by brand/age, what counts as “underlying,” off-label/insurance realities, why ACIP mainly affects coverage (not labels), a brief CDC leadership update, and practical protections—documentation, ventilation, high-filtration ...

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Back-to-school season means new teachers, new friends…and a whole new round of germs. From runny noses to strep throats, pinkeye to flu, classrooms are a breeding ground for illness once the school bell rings. In this episode of Infectious Dose, Heather breaks down the most common fall outbreaks in kids, when to keep children home, and the prevention strategies that actually make a difference.

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In this gripping episode, we dive into the world of Vibrio vulnificus—a flesh-eating bacterium once confined to warm southern waters, now making deadly appearances from Florida to Cape Cod.

We begin with real-life cases from the 2025 surge across the U.S., then uncover the science behind this microscopic killer: how it invades, how it spreads, and why it’...

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Chikungunya is sweeping through southern China in its largest recorded outbreak—and it’s not just a local problem. In this episode of Infectious Dose, Heather takes you inside Foshan’s summer surge, unpacks how this mosquito-borne virus travels the globe, and explores why its painful symptoms can linger for months or even years. You’ll hear how two species of mosquitoes are redrawing the map o...

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What do vaccines really contain? Why do people still believe they cause autism? And who keeps spreading these lies?

In honor of Immunization Awareness Month, this special episode of Infectious Dose is your guided tour through our vaccine safety series. Heather maps out the key episodes that break down myths, expose disinformation campaigns, and explain ...

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In this episode, Heather unpacks one of 2025’s most urgent and underreported global health crises.

Cholera—an ancient disease we know how to prevent and treat—is resurging across dozens of countries. But this isn’t about biology alone. From Sudan’s displaced families to Angola’s overcrowded clinics and the gold fields of the DRC, people are dying not from mystery—but from neglect.

You’ll learn what cholera is, how it spreads, how c...

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Rabies is one of the deadliest viruses known to science—but its cultural legacy may be even more enduring. Rabies has stalked the screen for decades, not just as a disease, but as a symbol of primal fear, uncontrollable rage, and the thin line between animal and human. This episode investigates the biology of rabies bites and its eerie neurological symptoms, while examining its transformati...

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This episode is a little different. After relaunching and dropping 18 episodes since April, Heather finally shares the personal story behind why she left her blog/podcast/social media—and why she came back. From life upheaval and burnout to pandemic loss and resilience, this is the story behind Infectious Dose. If you're new here, it's a great place to understand the mission behind the mic. A...

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As global focus drifts and vaccine narratives fade, polio—a disease once on the brink of eradication—is finding new paths to persist. In this episode, Heather unpacks the World Health Organization’s latest alerts on circulating vaccine-derived poliovirus (cVDPV2), explores newly issued travel advisories, and traces the virus’s quiet resurgence. From the politics of prevention to the myths that still haunt public memory, we examine ...

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This Fourth of July, we’re serving flaming absurdity alongside a tribute to scientists under attack. In this science-meets-comedy special, Heather tackles the patriotic chaos of backyard BBQs, rogue mortars, and the bacterial battleground of summer salads. Featuring real disaster stories, expert food tips, and a powerful closing tribute to U.S. scientists with an original poem that will leave you ready to Sta...

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More than five years since the start of COVID-19, the virus is still here — evolving, spreading, and leaving lasting impacts. In this episode of Infectious Dose, Heather—a virologist-turned-science writer—examines the costs of the erosion of protective messaging, what new data say about reinfection, and the risks of losing vaccine access under a shifting political landscape. From airborne transmission to long COVID, this episode un...

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What if our biggest mistake in vaccine communication wasn’t misinformation—but misexpectation?

In this episode of Infectious Dose, Heather digs into the seductive myth of sterilizing immunity—the idea that a “perfect” vaccine blocks infection completely—and explores how this scientific fable has distorted public expectations, undermined trust, and set back our ability to fight infectious diseases.

From the remote Faroe Islands in 1...

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In this episode, Heather delves into the story of Sin Nombre virus and the disease it causes, Hantavirus Pulmonary Syndrome. From its rodent origins and rapid progression to the public health response and scientific breakthroughs that followed, we explore how a rare virus rewrote the rules of infectious disease in North America—and why it remains a threat, even in obscurity.

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Heather gives updates on 2025 measles outbreaks in every region of the world and discusses global efforts to curb them. She also debunks the deadly lies about measles from RFK Jr. in her fan favorite segment WTF-RFK! and answers listener questions in her new segment Hot Zone Hotline. 

Explicit rating is for mild and limited profanity because, I mean, RFK. 

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Pregnant and wondering which vaccines are safe? Heather separates myths from facts & shares exactly what science says about vaccine safety during pregnancy—because you and your baby deserve the best protection!

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