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.

Episode 40: Vaccine Safety 9 - The FDA Memo That Betrayed Public Trust: What You Need to Know

A leaked FDA memo sparked headlines claiming the COVID vaccine killed children — but the memo included no evidence, no data, and no scientific analysis. In today’s episode, Heather unpacks what the memo actually said, why experts across the field immediately rejected its conclusions, and how vaccine safety is truly evaluated. She explains the real risks of COVID in kids, from MIS-C to long COVID, and why misinformation from inside federal agencies threatens public trust and puts families at risk. Clear, compassionate, and evidence-driven, this episode gives parents the clarity they deserve. NOTE: All sources are cited in the blog post for this episode at infectiousdose.com

12-10
19:38

Episode 39: Cold Comfort - What Winter Rituals Got Right About Microbes

There’s more to your favorite winter rituals than nostalgia. In this episode, we dive into how centuries of winter traditions—across Europe, Asia, Africa, and the Americas—offered accidental protection against infectious diseases. From citrus in stockings to cloves in mulled wine, from kimchi to candlelight, we trace how ancient practices around food, air, warmth, and cleaning helped communities stay healthier in the harshest season. Learn how: Spices like cinnamon, ginger, and clove helped preserve food and reduce pathogens Fires, feasts, and fermentation doubled as primitive infection control Cleaning rituals and seasonal isolation slowed the spread of disease Modern public health can still draw lessons from these old traditions We also address how today’s world—sealed homes, global travel, and misinformation—has changed the game, and why clear science is more important than ever. 🎙️ Plus: a discussion of the recent HHS decision under Robert F. Kennedy Jr. to remove the statement “vaccines do not cause autism” from federal pages—and why this political move contradicts decades of scientific evidence. See the corresponding blog post at infectiousdose.com for all citations.

12-03
19:50

Episode 38: Outbreak After Dark 2 - Pilgrims and Plagues

In this Outbreak After Dark episode, we revisit Thanksgiving’s origin story through the lens of infectious disease. Heather, Sam, and Kate dive into the epidemics that devastated Indigenous nations before the Pilgrims ever arrived, the microbial mismatches between Old World and New, and the narratives that still distort how we talk about “the First Thanksgiving.” It’s a campfire conversation that blends history, science, myth-busting, and respect for the communities whose histories were altered by plague long before the feast. All episode citations and recipes are in the blog post at infectiousdose.com

11-26
20:51

Episode 37: A Prescription for Pestilence - The Global Spread of Antimicrobial Resistance

This week’s episode dives into the roots of the global antimicrobial resistance crisis. How did routine cuts, UTIs, and pneumonias become untreatable? What systems helped superbugs evolve — and why is the problem accelerating worldwide? We explore the science, the policies, the failures, and the future of drug-resistant microbes in A Prescription for Pestilence: The Global Spread of Antimicrobial Resistance. NOTE: All cited references are linked in the blog post for this episode at infectiousdose.com

11-19
30:12

Episode 36: Rift Valley Fever - When Rains Bring Life and Loss

Rift Valley fever is back — and it’s hitting harder than it has in years. In this episode, we trace the 2025 outbreak from Mauritania to Senegal, explore how the virus hides between rainy seasons, and reveal what scientists have learned from unexpected hotspots in Tanzania. From mosquitoes and livestock to people and policy, this is Rift Valley fever: when the rains bring life and loss. Don't miss today's (Nov 12, 2025) free webinar on RVF: The World Health Organization is hosting a free EPI-WIN webinar at 1pm CET, which is 7pm EST called “Rift Valley Fever and Community Protection: Gaps, Needs and Priorities,” and it brings together experts from WHO, Senegal, and Rwanda.

11-12
26:32

Episode 35: Travel Bugs & Holiday Hugs - Staying Healthy on the Road

Headed into holiday travel season? This episode of Infectious Dose is your go-to guide for staying healthy on the road — without panic, shame, or disinfecting your entire row like you're filming a CSI episode. We talk practical prevention for planes, airports, road trips, and cruises, including how to avoid RSV, norovirus, and long COVID, what to pack in your health kit, why snacks matter, and how to travel with kids without losing your mind — or your mask. Smart tips, real science, and relatable chaos, all in one episode. NOTE: PDF Infection Prevention Travel Checklist available for listeners in the blog post at infectiousdose.com

11-05
29:38

Episode 34: Outbreak After Dark 1 - Ocularium

Welcome to Outbreak After Dark, a new monthly ritual within Infectious Dose, where the science stays real but the stories get darker, weirder, and yes—sometimes just plain gross. In this Halloween premiere, Ocularium, Heather is joined by cohosts Kate and Sam, to share true “medical horror” stories about parasites that call the eye home: Loa loa, Onchocerca volvulus, Acanthamoeba, and Thelazia gulosa. 🍂 Grab your themed snacks and cider, settle by the fire, and prepare to see infectious disease in a whole new light—if you can keep your eyes open. 🧠 Learn more and get the recipes at infectiousdose.com

10-29
31:09

Episode 33: The Sleep Lecture - A Case of Encephalitis Lethargica

What if you couldn’t wake up—and your mind kept trying to lecture its way out of the dark? In this week’s Month of the Macabre episode, “The Sleep Lecture,” a neurologist begins a talk on encephalitis lethargica—the mysterious “sleepy sickness” that swept the world a century ago—only to discover she’s become part of her own subject. Based on true clinical records and modern research, this immersive narrative blurs the line between dream and science, between consciousness and coma. Listen with the lights low. And maybe don’t fall asleep just yet.   Listener Note: The medical and historical details in this episode are based on real research, but the people and institutions are fictional. Any similarity to real individuals or places is entirely coincidental.

10-22
15:36

Episode 32: The R@VN - A Requiem for Antivaxxers

In this special Month of the Macabre episode, Infectious Dose steps into gothic territory with a haunting reimagining of Edgar Allan Poe’s The Raven—rewritten for the age of science denial. The R@VN follows a man who built his fame on rejecting vaccines and mistrusting public health—until a disease he dismissed returns to claim him. As paralysis sets in, his smart-home AI, the Rational Autonomous Virtual Nexus (R@VN), becomes both witness and judge, speaking in clinical tones that sound increasingly like prophecy. What begins as denial ends as digital haunting—a parable for the consequences of rejecting science. It’s fiction… but the danger is real. Listen to the end for a post-credits scene. 🪶 Listen for:– A modern retelling of The Raven with Poe’s original rhythm and rhyme– The intersection of technology, hubris, and health– How polio still haunts us—and why vaccine denial makes it rise again 💉 Related episode: A Plague Returned Note: R@VN is a fictional artificial intelligence system created for storytelling purposes. Any resemblance to actual products, companies, or technologies is purely coincidental. The R@VN is inspired by Edgar Allan Poe’s “The Raven” (1845), now in the public domain.

10-15
15:00

Episode 31: Salem 1692 - The Grain, the Gallows, and the Whispering Tapes

In 1692, the people of Salem believed the Devil walked among them. But centuries later, scientists and historians would wonder: could the culprit have been something far more earthly—a hallucinogenic fungus lurking in their daily bread? This Month of the Macabre episode of Infectious Dose examines the ergotism theory behind the Salem witch trials, blending science, history, and haunting “found tapes” that may hit too close to home. From convulsive fits and crawling skin to the toxic fungus Claviceps purpurea, we explore the blurred line between infection and imagination—and how fear itself became contagious. Listener note: this episode doesn’t end where you think it will.  See the blog post at infectiousdose.com for more information.

10-08
20:02

Episode 30: Pneumonia Noir - A Mystery Written in Fog and Fever

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 fragile—our public health defenses can be. Pair this one with The Andromeda Strain or The Bay and get ready for a suspenseful story of fog, fever, and fieldwork.

10-01
34:20

Episode 29: Surveillance, Research Rules, and Preparedness - A Conversation with Jim Alwine, PhD

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 recent regulatory changes are limiting the ability of U.S. scientists to study viruses...and what systems we urgently need to restore if we want to be ready for the next pandemic. Take Action: https://www.defendpublichealth.org/get-involved Further Reading & Resources: TWiV 1121: SARS-CoV-2 Still Didn’t Come from a Lab https://www.microbe.tv/twiv/twiv-1121/  Oversight of Pathogen Research Must Be Carefully Calibrated (J. Virol.) https://journals.asm.org/doi/10.1128/jvi.00176-23 Virology Under the Microscope: A Call for Rational Discourse https://journals.asm.org/doi/10.1128/jvi.00089-23 Improving the Health of America Together – DPH https://www.defendpublichealth.org/resource/improving-health-americans-together-evidence-based-framework-addressing-root-causes Field Research Is Essential to Counter Virological Threats (J. Virol.) https://journals.asm.org/doi/10.1128/jvi.00544-23 🔗 Full article links, summaries, and transcript: infectiousdose.com/jim-alwine

09-24
37:16

Episode 28: From Evidence to Power - Organizing for Public Health with Jon Shaffer, PhD

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 more from each of us. In this episode: • Why public health is inherently political—and what it costs to ignore that • Organizing vs. advocacy vs. lobbying (and why teams are the power unit) • What a mini-campaign looks like and how it strengthens a new team • Overcoming fear with relationships, stories, and clear, winnable demands • Why state-level organizing fits local political culture—and actually wins Take action: • Join a digital action today: https://www.defendpublichealth.org/get-involved • Set up a 1:1 with Jon to plug into a state team: jonshaff@gmail.com                                        Disclaimer: Views expressed by guests are their own. (Full blog post + transcript at infectiousdose.com )

09-17
01:02:12

Episode 27: Neuro Invasion - The Silent Siege of West Nile Virus

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 devastating attack on the nervous system. With no proven treatments and no human vaccine, prevention remains our best defense—making this one of the most enduring mosquito-borne threats in the U.S. and beyond.

09-10
23:35

Episode 26: Not Smarter, Just trained - How I Sort Fact from Fiction

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.

09-03
40:09

Episode 25 1/2: Booster Dose - New COVID Vaccine Access Explained

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 masks, testing, and an antiviral plan.

08-28
14:37

Episode 25: Classroom Contagions - A Back-to-School Survival Guide

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. You’ll also hear about the role vaccines play in keeping kids healthy, what to do if masks aren’t welcome in your school, and how new attendance policies—like the controversial one in Tennessee—make it even harder for parents to do the right thing. This episode is a practical, parent-friendly guide to surviving sick season with sanity intact.

08-27
52:58

Episode 24: No Boat Big Enough - The Rise of Vibrio Vulnificus

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’s rising globally. From wound infections to raw oysters, climate change to coastal vulnerability—this is a public health warning. Because with Vibrio vulnificus, a bigger boat won’t help.

08-20
31:55

Episode 23: Blood and Bone - The Battle Against Chikungunya

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 of where chikungunya can strike, why genetic changes have made it more adaptable, and what public health responses—from targeted mosquito control to controversial government overreach—look like on the ground. Whether you’re a traveler, a science enthusiast, or just someone who hates mosquito bites, this is your deep dive into the past, present, and future of a virus that won’t stay put.

08-13
38:04

Episode 22: Booster Dose - A Guided Tour Through the Infectious Dose Vaccine Safety Files

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 the real science behind some of the most common vaccine fears. From “Too Many Too Soon” to the truth about mRNA vaccines and RFK Jr.’s ACIP overhaul, this curated “booster dose” is perfect for new listeners, long-time followers, or anyone seeking facts they can trust. Use it to figure out which episode to listen to next or share with a friend on a quest for the truth about vaccines, who's not sure where to start.

08-06
24:48

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