The hantavirus outbreak on the luxury cruise ship MV Hondius has reignited old hoaxes and conspiracy theories on social media. As with the COVID-19 pandemic in 2020, hordes of misinformation and seemingly serious claims, lacking any scientific basis, have once again spread around this new outbreak, which is of a completely different scale and nature than the pandemic of six years ago.
So far, the World Health Organization (WHO) has confirmed eight cases linked to the outbreak, including three deaths. And although person-to-person transmission of hantavirus is rare — the most common route is through contact with rodent droppings — health authorities are monitoring all passengers on the ship and several dozen people outside the cruise ship who may have come into contact with one of the infected cases.
The cruise ship, carrying approximately 150 people, will arrive in Tenerife, in Spain’s Canary Islands, on Sunday. On Monday, crew and passengers will be repatriated: foreigners to their countries of origin and Spaniards to the Gómez-Ulla Military Hospital in Madrid, where they will be quarantined according to health protocols.
A surge in new cases is not expected, but comments and theories on social media are running rampant, fueling panic about an epidemic similar to the 2020 COVID-19 pandemic. These are the most common conspiracy theories circulating online:
It is the beginning of a new pandemic
There is no scientific evidence or epidemiological indication that this hantavirus outbreak will spread massively. First, because its transmission between humans is not very efficient: the virus’s main reservoir is a specific type of rodent that is not found worldwide; and, although person-to-person transmission is possible —it has been described in the Andes variant, which is the one circulating on the cruise ship — it is very rare. An example of its limited transmission is the fact that the vast majority of people on board the ship are apparently healthy, without any symptoms.
Experts say that more cases may emerge, but they predict very local transmission, rather than a large epidemic.
It is an unknown virus
That’s not true. Unlike SARS-CoV-2, which was completely unknown when it triggered the pandemic in 2020, hantavirus is a microorganism that has been known since the 1950s. It was first isolated in the 1970s, and cases occur every year in many countries. The WHO estimates that there are between 10,000 and 100,000 infections annually, concentrated mainly in East Asia and Northern and Central Europe, where the disease is endemic but mild. In the Americas, cases are much less numerous (just a few hundred per year across the entire continent) but more severe, with a fatality rate of between 30% and 50%. The variant circulating on the cruise ship is the Andes virus.
It’s all a scientific experiment and a plan to get rich off vaccines
Conspiracy theories always spring up in response to health crises of this kind. They never go away. In fact, social media tends to recycle the same arguments for different scenarios. The idea that everything is a scientific experiment to wipe out the planet’s population, that the virus escaped from a laboratory, or that the health emergency is an operation orchestrated by the pharmaceutical industry to profit from vaccines are narratives that resurface periodically whenever there is a public‑health alert.
It is true that some companies are researching therapies against hantavirus infection, but currently there is no treatment for the disease nor any preventative vaccines. There is also no scientific evidence to suggest that the outbreak originated in a laboratory: the WHO’s main hypothesis is that a Dutch couple, who are among the deceased, “were infected off the ship.”
The cruise ship passengers spread the virus to other islands
While it is true that the cruise ship stopped at some remote Atlantic islands before the outbreak was reported, and about 30 passengers disembarked on the island of Saint Helena to return to their home countries, there is no evidence that they were infected when they left the ship, much less that they transmitted the virus to other people or the local population. The incubation period is long — between one and eight weeks — but the likelihood of the virus being transmitted during that phase, and when the person has no symptoms, is extremely low.
For now, the WHO, which is monitoring the group that disembarked in Saint Helena and the passengers of a plane from Johannesburg where the Dutch woman who died from the virus traveled, has only confirmed one case of hantavirus among the passengers who disembarked midway: a Swiss man who left the trip at an as yet undetermined point in the journey, and returned with his wife to his country at the end of April and is now being treated at the University Hospital of Zurich.
Hantavirus is more dangerous than coronavirus
The pathogen detected on the cruise ship has a higher fatality rate, but it is better understood and far less contagious than SARS‑CoV‑2. Hantavirus does not transmit easily between humans, and the reservoirs of the Andes variant — long‑tailed mice — are not found in all regions. Neither the rodent species nor the virus is present in Spain.
That said, the clinical course of hantavirus can deteriorate within hours, and the fatality rate of the respiratory syndrome can reach 50%. By contrast, in 2020 the estimated fatality rate for coronavirus was 1.7%, with huge differences by age (from 0.01% in children aged one to 14 to 23.6% in those over 85).
At present, epidemiological risk assessments place the danger level in Spain and Europe as very low. Experts say this is not a public‑health emergency. On Wednesday, the Spanish Ministry of Health issued a call for calm: “Person-to-person transmission is practically nonexistent. Until now, there had been isolated cases of person-to-person transmission in 1996 and 2018, with one strain, the Andes virus. It is the same strain present on the ship, but transmission occurs in the first few days of the illness and is only possible through sustained and close contact.”
The infection can be cured with ivermectin, vitamin D or zinc
There is no known cure for hantavirus infection, but social media is awash with supposed treatments and products claiming to eliminate the disease. Some users have promoted ivermectin — an antiparasitic drug — as a safe and effective therapy against hantavirus. But there is no scientific evidence to support that claim. Ivermectin was also touted as a remedy for COVID-19, and regulators such as the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) had to step in to warn against its use and to reiterate that no studies demonstrated its effectiveness against the coronavirus.
I actually texted her today and asked what can we treat hantavirus with. I’m so glad she posted it.
Ivermectin.
Also vitamin D and zinc.
Those of us who refused to lockdown, mask up, and get vaxxed took the good ole horse paste and also developed natural immunity. https://t.co/m3mag0hhBm— Former Congresswoman Marjorie Taylor Greene🇺🇸 (@FmrRepMTG) May 6, 2026
Other messages on social media also suggest that vitamin D or zinc might help, but this claim also lacks scientific validity. Currently, there is no specific treatment for hantavirus. Only palliative care is available. According to the Spanish Health Ministry, medical attention focuses on “relieving symptoms and helping to maintain stable breathing and vital signs with oxygen therapy, mechanical ventilation if necessary, and hemodynamic stabilization in intensive care.”
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