90-Second Read: Tools to Fight Hantavirus Show Promise Despite Limited Funding

Researchers on Wednesday published a hint that a drug used for an autoimmune disease may help Hantavirus patients fight off the most deadly symptoms. The Andes virus, the germ behind the cruise ship outbreak, is a particular focus of researchers because it is the only Hantavirus thought to be able to spread between people in some cases. Separately, in Chile, the Ministry of Health has confirmed 15 deaths and 42 cases of Hantavirus so far this year. They and others hope the attention that the cruise ship outbreak brought to the virus -- and concern that Hantavirus infections could become more common as a changing climate is expected to increase contact between people and rodents -- may bring new momentum to the hunt.

In the U.S., 35% of the Hantavirus cases since tracking began in 1993 have resulted in death, according to the CDC. Four of five patients in an Argentinian hospital survived after receiving tocilizumab in addition to traditional supportive care for Hantavirus pulmonary syndrome, the research team reported in the Lancet Infectious Diseases. Vaccines against so-called Old World Hantaviruses have been developed and used, though the World Health Organization says there are no current licensed Hantavirus vaccines. Authorities in Argentina have reported 32 deaths and 102 cases since June 2025.

But because the viruses are relatively rare and don't spread easily between people, there hasn't been enough sustained investment by governments, global health groups, or drug companies to pay for the extensive safety and efficacy testing needed to make them available. Different Species of Hantavirus Cause Different Symptoms Hantaviruses usually spread when people inhale contaminated residue of rodent droppings. But there are unique species of Hantavirus found in different parts of the world that have their own characteristics and can cause different symptoms. And while Hantavirus infections are rare, they can be extremely deadly.

But there are new vaccines in the works, including ones aimed to fight the Andes virus. Also, because Hantavirus outbreaks are so sporadic and unpredictable, that virus is much harder to study compared with a common germ that regularly circulates, such as the flu. The report is unusual, tracking the first people to receive tocilizumab in an ongoing "compassionate use" study -- meaning doctors can use it in patients they deem eligible.