The World Health Organization received its first report of a hantavirus outbreak aboard the Dutch-flagged cruise ship MV Hondius on May 2. Two days later, health officials identified it as the Andes strain: the only hantavirus known to spread from person-to-person in rare cases, prompting a surge of misinformation, theories and false claims across social media.
In less than three weeks, the hashtag #hantavirus amassed nearly 406K posts on TikTok alone. Viral videos described the outbreak as “coronavirus 2.0,” warned that “we’re all doomed,” joked about “practicing dance moves for this next round of lockdown" and falsely claimed a “hantavirus rapidly mutating virus update.” Much of this content circulated faster and reached wider audiences than official public health messages, amplifying public anxiety.
“In this day and age, when you have the ubiquity of social media and AI, information can just travel so fast,” said Prof. Katherine McComas, Ph.D. ’00, communication. “There are some people who are well-meaning [that are] sharing information, but there are also bad actors who are profiting off of having more people click on their posts.”
Why the Real Danger is Extremely Low
Despite mass online anxiety, experts emphasize that the risk posed by hantavirus to the general public is low.
Unless individuals were actually on the ship or in close contact with someone who was, they “really shouldn’t be concerned about being infected with hantavirus,” said Prof. Raina Plowright, veterinary medicine. Plowright is an epidemiologist who specializes in zoonotic diseases — diseases that spread between animals and humans — such as hantavirus.
Most hantavirus infections occur due to zoonotic spillover, Plowright said. In these cases, a primary risk factor is accidental exposure to aerosolized rodent droppings, which could occur while sweeping a dusty garage.
Between humans, hantavirus transmission is even rarer. The Andes strain, the only known variant that spreads between humans, is only transmitted through close contact between individuals, such as prolonged exposure from sleeping in the same bed — not simply sitting next to someone at a bar, Plowright explained. This high level of prolonged closeness required for human transmission makes preventing the spread of the disease easier.
“You can identify sick people, isolate them and then you can do contact tracing and find out who they've had close contact with and then [quarantine] those people,” Plowright said. “You can quickly bring the outbreak under control.”
In contrast, SARS-CoV-2 — the virus that causes COVID-19 — spreads much more easily, which made it “very, very hard to control the outbreak,” Plowright said.
The Roots of Public Panic
Despite the low risk that experts say the general public faces, there has been a substantial amount of panic surrounding hantavirus. The apparent paradox is “fascinating” to McComas.
The science of risk communication can make sense of this, she said. One reason behind the panic observed in the public response to the hantavirus outbreak, McComas explained, is the psychological tendency to associate unfamiliar events with familiar ones.
“We know that when people are unfamiliar with a risk, they tend to associate it with things that they are more familiar with,” McComas said. “And so that's why people may associate [hantavirus] with other types of infectious disease or pandemics.”
For Americans for whom the COVID-19 pandemic is still a recent memory, hearing about an outbreak of an unfamiliar zoonotic virus in another country could lead them to associate hantavirus with COVID-19 — and maybe even prompt “COVID PTSD.”
When people are exposed to a personal anecdote of a risk issue, where the severity or consequences of that risk are emphasized, they may perceive it as a greater risk than it really is, McComas said.
The first patients to contract hantavirus on the MV Hondius have received extensive press attention, which even resulted in The New York Times’s use of birdwatching data to create a map of their whereabouts for the month prior. The publicity of this single, poignant example may heighten the public’s perceived risk of the outbreak.
Channels like social media also play a role in public responses to risk events. Social media algorithms can spread misinformation quickly and generate echo chambers, selectively exposing audiences to information that confirms their beliefs and magnifying the perception of threat.
The Bigger Risk
While public attention remained on hantavirus, Plowright said scientists are more concerned about preventing Disease X, also called Pathogen X, a WHO term representing an unknown hypothetical future pathogen that could cause a serious international epidemic or pandemic.
“From all the information that we have currently, we’re not at risk from this hantavirus,” Plowright said. “What we really worry about is Pathogen X, … the undiscovered, uncharacterized virus that’s probably circulating somewhere in nature. And it hasn’t found the right interface to be able to transmit from animals to humans.”
Although no one can predict when the next Disease X will emerge, scientists say that these outbreaks are becoming increasingly frequent due to environmental change.
Human activities such as deforestation, mining, wildlife trade and hunting are rapidly altering animals’ habitats and food sources. These disruptions can stress wildlife, leading them to migrate to new environments that are often populated with humans, increasing opportunities and risk for zoonotic spillover, according to Plowright.
In preparation for Disease X, researchers are now developing vaccines by targeting shared elements among known pathogens, which could allow for a prompt intervention when a similar pathogen emerges.
But vaccines alone are not enough to prevent future pandemics, according to Plowright, who emphasized the importance of an established global alliance that plans for and guides the public in the event of an outbreak. For example, the WHO launched an international Pandemic Agreement in 2025 to improve future pandemic responses. The U.S. is currently not part of WHO or the international Pandemic Agreement.
“The United States sits on the outside now. … I think as a country, it's in our best interest to be on the inside and to have the most updated information and be a part of an international coordinated response, not a separate response, ” Plowright said. “There's no doubt it is in our best interest for the health [of the population] to be in WHO.”
These coordinated global resources are especially important for communicating credible messages during an outbreak, helping prevent the recurring pattern of public speculations and misinformation, Plowright said. This emphasis on coordination points to a broader challenge: how to ensure such clear and credible communication in times of crisis.
Towards a Risk Communication Infrastructure
For risk communication researchers, the hantavirus outbreak and the COVID-19 pandemic have revealed the need for improved risk communication in potential future outbreaks.
Part of improving risk communication includes building infrastructure for this communication on a federal level, McComas noted.
“What we have learned through … other types of crises like this is that we have to build important infrastructure systems of risk communication [such] that we're able to respond when these next crises happen,” McComas said. “We want to try to prevent them, but we have to be able to respond to them.”
One key strategy is creating crisis communication plans for any organization, whether Cornell or a cruise ship, that detail how it will respond to a given crisis.
A good crisis communication plan “provides a clear structure for how to respond,” McComas said. “Who is going to be the spokesperson for this? Who needs to be contacted? All of this is laid out in your crisis communication plan.”
The end goal of building risk communication infrastructure is that institutions like the Centers for Disease Control and Prevention or WHO possess what communication researchers call “surge capacity,” according to McComas — the ability to reach out to allies and networks in a crisis to scale up risk communication operations, such as implementing institutional risk communication advisory councils.
For example, the U.S. Food and Drug Administration has a Drug Safety and Risk Management Advisory Committee, and the National Academies of Sciences, Engineering, and Medicine hold a Standing Committee on Advancing Science Communication.
Finally, building a strong communication infrastructure requires building trust between experts and the public, especially after the decline in public trust in health officials after the COVID-19 pandemic.
Unlike what many scientists may assume, there are many different antecedents of trust beyond scientific expertise, McComas said. Factors such as whether people believe sources share similar values may also affect their judgements on whether or not to trust a source.
“We have to [first] understand what has caused us to lose the trust and then we have to actively work to respond to that,” McComas said. This can include allying with trusted sources like religious leaders to target audiences in different communities and allowing people to voice their concerns, she added.
Above all, McComas emphasized the importance of investing in risk communication.
“In crisis communication, you really can be proactive,” McComas said. “You don't just have to be reactive. And the best is to be as proactive as possible.”
Building Trust in Science
For both experts, the response to the current hantavirus outbreak shows that preparing for Disease X will require not only vaccines and crisis communication plans, but also restoring public trust in scientists and health authorities.
“By supporting science, we really are supporting the public good,” Plowright said. “We’re supporting a lot of people working incredibly hard to try to do things that make our lives better.”
