Resolution criteria

This market will resolve to YES if the total number of confirmed measles cases in the United States reported by the Centers for Disease Control and Prevention (CDC) for the calendar year 2027 is strictly greater than the total number reported for the calendar year 2026. If the 2027 count is less than or equal to the 2026 count, the market will resolve to NO.

The primary source of truth will be the CDC's official Measles Cases and Outbreaks page. If this page is unavailable or no longer updated, official numbers published in the CDC's Morbidity and Mortality Weekly Report (MMWR) or the National Notifiable Diseases Surveillance System (NNDSS) will be used.

Details and Edge Cases:

• The resolution will rely on "confirmed" U.S. cases as defined and tracked by the CDC.

• Because weekly provisional numbers are subject to revision, the market will resolve using the final consolidated case numbers for each year as published by the CDC (typically updated in the first half of the following year). If the cumulative provisional count for 2027 exceeds the final 2026 count at any point, the market may resolve immediately to YES. Otherwise, resolution will wait until near-final or final counts for both years are available, no later than June 30, 2028.

Background

Measles was declared eliminated in the United States in 2000 due to high vaccine coverage, but imported cases and subsequent transmission in under-vaccinated pockets continue to cause periodic flare-ups.

The U.S. experienced a significant resurgence of measles starting in 2025 (which saw 2,289 confirmed cases). In 2026, the outbreak worsened, with the CDC reporting 2,318 confirmed cases by late July 2026—making 2026 the worst year for U.S. measles infections in 35 years. This market tracks whether this rising trend of case counts will persist into 2027, or if public health containment strategies and vaccination campaigns will succeed in bending the curve downward.