Infectious Dose

Nipah virus scares virologists, and for good reason. It infects endothelial cells and neurons. It can cause fatal encephalitis. It spreads from bats to humans, and sometimes between people. So why does it keep burning out? In this episode of Infectious Dose, we examine:

Henipavirus biology and receptor usage (ephrin-B2/B3)

Why neurotropism drives severity

Why outbreaks are small but deadly

Why R₀ remains low

What would actually have to change for Nipah to go pandemic

Why spillover keeps recurring in Kerala

And why survival does not always mean full recovery

This is a grounded look at pandemic thresholds — not panic headlines.

Preparedness requires vigilance not hysteria.

All citations in the companion blog post at infectiousdose.com

Syphilis is back—and it never really left. In this episode, we break down how a curable, preventable infection is resurging to cause a public health crisis across the U.S., and globally, especially among pregnant people and newborns. We unpack the science behind Treponema pallidum, the public health failures driving the crisis, and why trust in health systems is still broken—from Tuskegee to today. Plus: what you need to know about testing, treatment, and why a shot of penicillin makes all the difference.

Sources at Infectiousdose.com

This short, standalone episode is a statement of ethics.

It explains why this podcast will not remain silent in the face of state violence, the dismantling of public health, and the normalization of harm against vulnerable people. It clarifies the ethical boundaries that guide the work behind Infectious Dose: that science is for everyone, but cruelty, authoritarianism, and the protection of abuse are not neutral positions.

This episode is not a scientific explainer and not an invitation to debate. It exists to make clear where this podcast stands, why silence is not an option, and why evidence, accountability, and human rights are inseparable from public health.

RSV is one of the most common respiratory viruses — and a leading cause of hospitalization in young children worldwide.

In this solo episode, I explain what RSV is, how it spreads, and what illness typically looks like in babies, children, and adults. We cover when RSV can be managed at home, how to recognize breathing-related red flags, when to go to the ER or call an ambulance, and what supportive care actually helps.

The episode also looks at the current RSV landscape, including rising cases in parts of the U.S. and new prevention tools — maternal vaccination and long-acting monoclonal antibodies — that are dramatically reducing severe RSV disease in infants. Clear, practical, and evidence-based.

https://www.healthychildren.org/English/health-issues/conditions/chest-lungs/Pages/RSV-When-Its-More-Than-Just-a-Cold.aspx

Spiders inspire some of our deepest fears—but are they actually as dangerous as we think? In this Outbreak After Dark episode, Heather, Sam, and Kate dig into the real science behind spiders, venom, and so-called “spider bites,” separating evidence from exaggeration. Along the way, they unpack persistent myths, medical misattribution, and why spiders loom so large in outbreak lore—despite rarely being the culprit. Creepy? Yes. Deadly? Usually not. Welcome to Outbreak After Dark.

Editor's Note: While this episode leans into humor and fear, spiders play an important ecological role and are rarely a danger to humans. 

See companion blog post at infectiousdose.com for full transcript and references.

What are biological weapons—and what are they not?

In this episode, Heather is joined by bio-risk consultant and biodefense researcher Conor Browne for a grounded, reality-based conversation about biological weapons, biodefense, and why public discourse around these topics so often goes wrong.

Together, they unpack what actually defines a biological weapon, why intent and delivery matter, and how real historical programs differ from the conspiratorial narratives dominating social media and politics. They explore state and non-state capabilities, the real constraints involved in weaponization, and why most pathogens—even deadly ones—are not practical weapons.

The conversation also tackles some of today’s most misunderstood ideas, including gain-of-function research, lab accidents versus deliberate release, dual-use research of concern (DURC), and the limits of attribution when outbreaks occur. Along the way, Conor explains why sloppy language isn’t just misleading—it can actively undermine public health and national security.

This episode is a clear-eyed look at biological threats without fear-mongering, designed to replace panic with understanding and precision.

Topics covered include:

What actually qualifies as a biological weapon

Why dangerous pathogens ≠ weapons

Historical bioweapons programs and what they really looked like

State vs. non-state actor capabilities

Why lab accidents are not weapons

Gain-of-function research, DURC, and political distortion

How misinformation increases real biological risk

In this episode of Infectious Dose, Heather McSharry talks with Terry Virts—retired NASA astronaut, Air Force colonel, and candidate for Congress in Texas—about what happens when leadership ignores science.

Drawing on his experience in aviation, spaceflight, and risk analysis, Terry discusses the real-world consequences of sidelining evidence in public health, climate, and emergency preparedness. The conversation covers COVID-era misinformation, vaccines, measles outbreaks, healthcare access in Texas, and the dismantling of scientific institutions.

The episode also explores the parallels between spaceflight safety systems and high-containment biosafety labs—highlighting why science-based leadership isn’t optional when lives are on the line.

🔗 A full transcript PDF is available in the companion blog post at InfectiousDose.com. And Terry's campaign website is: https://www.terryvirts.com/

Follow Terry: @AstroTerry on Insta/Twitter/Bluesky and astro_terry on Threads

Follow Heather: @pathogenscribe on Insta/Twitter/Bluesky/Threads

This week in “Seasonal, Not Safe,” we confront the truth about influenza in 2025–2026. It’s not “just the flu.” From the tragic stories of children lost to fast-moving infections, to the science of how influenza spreads, mutates, and turns deadly — this episode explores what’s really happening this season. We break down the rise of Subclade K, current global flu patterns, new U.S. vaccine policy controversies, and what makes the flu virus so evasive. Plus: how antiviral medications work, why vaccination rates are falling, and what’s coming next in the push for a universal flu vaccine. 

All citations and updates available in companion blog post at infectiousdose.com

This New Year’s Eve episode isn’t about resolutions — it’s about a reset.

In Still Curious: A New Year’s Reset (Without Resolutions), Heather reflects on a difficult year for science, public health, and trust, and makes the case for curiosity as a quieter, steadier way forward. Rather than focusing on optimism or big promises, this episode explores what it means to pause, to stay engaged without burning out, and to carry curiosity into the new year even when certainty feels loud.

The episode closes with a gentle midnight mantra for anyone listening alone, early, or in need of calm at the turn of the year.

Companion blog post at infectiousdose.com

This month’s Outbreak After Dark is a special holiday episode — and a heavier one.

In A Consumption Christmas Carol , we reimagine Dickens’ classic ghost story through the real epidemic that haunted Victorian London: tuberculosis. Long before antibiotics, TB shaped daily life, art, poverty, and policy — romanticized in parlors, devastating in tenements, and deadly across all social classes.

Guided by familiar spirits of past, present, and yet to come, we trace how tuberculosis was misunderstood, aestheticized, and ultimately revealed as an airborne infectious disease — one that remains among the world’s deadliest today. This episode blends historical storytelling, medical science, and reflection on why some diseases never truly stay in the past.

Because this is a weightier story, we close the episode gathered by the fire for a post-Carol decompression — sharing snacks, drinks, behind-the-scenes thoughts, and space to process the history together.

🕯️ Outbreak After Dark is the after-hours storytelling series of Infectious Dose, where science, history, and a little gothic atmosphere meet. 

This episode is an original reimagining inspired by Charles Dickens’ A Christmas Carol.