For now, prediction market traders aren't too worried about the hantavirus.
Kalshi data shows only a 21% chance of the hantavirus outbreak will be a concern this year. The prediction markets platform opened its market on the hantavirus on Wednesday night, noting it will be resolved if the World Health Organization verifies that the virus is "a public health emergency of international concern" in 2026.
Compared to other markets opened on the same day, trading in this market has been high. On Friday, volume related to the outbreak hit over $174,000, the highest out of any market that opened in that time.
The WHO identified the virus as an outbreak on May 4, according to the Associated Press, a few weeks after several passengers on a Dutch-flagged cruise ship sailing the Atlantic Ocean grew ill. An outbreak is when there are a higher number of people catching diseases than what is expected within a specific community, geographic location or season, the WHO's website states.
The fatal and viral respiratory disease is transmitted through urine, feces or saliva of infected rodents and by touching contaminated surfaces, according to the WHO.
Spanish health officials said Friday that a woman in the country's southeastern region has symptoms consistent with hantavirus, Reuters reported. In the Netherlands, three people with symptoms of the virus tested negative.
That said, the WHO said the public health risk for the virus is low.Â
"While this is a serious incident, WHO assesses the public health risk as low." Director-General Tedros Adhanom Ghebreyesus told the media. "It's possible that more cases may be reported."
The WHO reported that there were a total 147 passengers and crew members on board the cruise ship. A former Centers for Disease Control and Prevention official and another person familiar with the matter told CNBC this week that six states are monitoring passengers who were on the cruise and have since returned to the U.S.
Those states are Arizona, California, Georgia, Texas, Virginia and New Jersey. Health departments from Arizona, Georgia and Texas said the former passengers have not shown symptoms.Â
Disclosure: CNBC and Kalshi have a commercial relationship that includes customer acquisition and a minority investment.
