I learned about hantavirus misinformation this week in the same way I now learn about most public health misinformation: My followers sent it to me.
Within hours of the first headlines about a hantavirus outbreak linked to the expedition cruise ship MV Hondius, my DMs started filling with screenshots. One was from the account of a Texas doctor who became well known during Covid for promoting ivermectin. She was already telling followers that ivermectin would work against hantavirus, too.
Some of the messages were from worried parents. Some were from people who had already been told by family members that ivermectin was the answer. A few were from longtime followers who simply wanted me to know it was happening, as if reporting a fire. By the time I sat down to film a video about the outbreak, I had a queue of misinformation to address that I had not yet even seen circulating in my own feed. The audience I built to push back against false claims has, over time, become something closer to a distributed early-warning system.
At this point, the speed of it barely surprises me anymore.
I’m an epidemiologist and a professor at a school of public health, and over the past four years I’ve built a large social media audience largely by debunking medical misinformation in real time. The people who follow me have gotten good at spotting misinformation, too. Before public health agencies even release detailed guidance, they can usually tell where the conspiracy ecosystem is headed next.
This time they were right.
The hantavirus outbreak itself is serious but limited. Eight cases have been linked to a cruise ship called the MV Hondius. So far, three of the cases have been fatal. The strain involved, Andes hantavirus, is the only hantavirus known to spread person to person, but it generally requires prolonged close contact. The World Health Organization currently considers the broader public health risk low.
There is no specific antiviral treatment for hantavirus. Supportive care is the standard treatment. And ivermectin does not treat hantavirus.
But online, the actual facts of the outbreak almost immediately became secondary.
Within a day, social media accounts were claiming the outbreak had been caused by Covid vaccines. Former Rep. Marjorie Taylor Greene amplified the framing, writing that pharmaceutical companies “manipulate the virus, make the vaccine, and then make the profits.” Other accounts warned followers not to take a hantavirus vaccine (one does not exist). Some called the outbreak a pharmaceutical scheme. Others called it a Chinese bioweapon. I saw posts referring to it as “Covid 26.” The hashtag #HantaVirusHoax was filling up with new posts hourly, many from accounts that had run nearly identical playbooks during Covid, mpox, and bird flu.
The claims contradict one another constantly. That doesn’t slow them down at all.
That’s the part I think many people still misunderstand about modern health misinformation. It no longer behaves like a random collection of rumors. It behaves more like an infrastructure: a standing network of influencers, conspiracy accounts, partisan personalities, and monetized outrage pages that speak with authority, rapidly attaching themselves to any new outbreak or health scare. They spread misinformation, it goes viral, and then they monetize whatever potions they are selling at the link in their bio.
The individual claims almost matter less than the cycle itself: See a new disease. Distrust the official explanation. Assume a coverup. Mention ivermectin. Suggest a hidden profit motive. Repeat.
During Covid, this process sometimes took weeks to fully build momentum. Now it happens within hours. This time I saw scientists on social media joking about imminent conspiracy claims before the first major misinformation posts had even appeared. We all know the script.
One of the strangest examples circulating in my messages wasn’t even from this year. People were reposting a social media prediction from 2022 that said: “Corona ended, 2026: Hantavirus.” It was being framed as evidence that the outbreak had been planned years in advance.
But conspiracy accounts make endless predictions. Most are wrong and quickly forgotten. But if one vaguely lines up with reality years later, it gets resurrected as “proof.”
I worry people underestimate what repeated cycles like this are doing to the public psychologically.
Most public health experts are focused, understandably, on whether a specific outbreak is large or small, contained or spreading. But every outbreak now also functions as an opportunity to monetize on viral misinformation. Each cycle conditions more people to approach infectious disease stories through the same preloaded assumptions: The cure is being hidden, the government is lying, scientists are corrupt, vaccines are the real threat.
And increasingly, those messages are not coming from fringe corners of the internet.
Pew Research Center data published this week found that half of Americans under 50 get health and wellness information from influencers and podcasts. Many of the people shaping those conversations present themselves as medical experts despite having little or no relevant expertise.
That audience is enormous. And it’s growing.
So, when a future outbreak with real pandemic potential eventually emerges, and one will, millions of people will encounter it inside an information environment already primed to distrust public health guidance before it even arrives. The narratives are prewritten now. The audience already knows the cues.
What worries me most is not that misinformation exists. It’s that we’ve started treating this environment as normal.
Katrine Wallace is an epidemiologist, researcher, and a professor at University of Illinois Chicago School of Public Health. She also debunks misinformation and educates about disease outbreaks on her popular social accounts as “Dr Kat, Epidemiologist.”
