According to a new report, gamblers in the United States have bet millions of dollars on measles outbreaks using prediction markets. Since January alone, nearly $9 million has reportedly been bet on measles using Kalshi and Polymarket.
In 2025, the U.S. Centers for Disease Control and Prevention reported 2,065 confirmed cases of measles in the United States. In 2000, the year health officials officially declared measles eliminated in the United States, only 85 people nationwide reported infections. The U.S. recorded just 285 cases in 2024. In 2025, Texas alone reported 803 cases of measles. So it is a growing problem.
People betting on measles outbreaks isn’t all bad
Now, as bizarre as it may sound, and putting aside the ethical considerations of betting on a potentially deadly infectious virus, those who study such things can see a positive side to people betting millions of dollars on measles outbreaks.
Spencer J. Fox at Northern Arizona University, who forecasts COVID-19, influenza and the respiratory virus RSV, tells New Scientist that people betting on measles outbreaks using prediction markets may prove to be a promising source of data.
“Everyone is looking for an edge for forecasting infectious diseases, and we’re constantly on the lookout for new data streams,” said Fox.
For example, in June 2025, prediction markets projected there would be around 2000 cases of measles in the United States by the end of the year. They weren’t off by much.
Prediction markets won’t, however, ever replace real science. One reason for this, according to New Scientist, is that they don’t provide as much granularity or integrate as many diverse forecasts on potential future outcomes as scientific models do.
“You would have to make 1000s of bets a week for all of the different forecasts that we’re making,” said Fox, adding that predicting measles is much easier than predicting more rare health events like COVID-19.
“If we don’t invest in the expertise for forecasting infectious diseases now, we’re going to be caught flat-footed,” he said.