Measles is a highly contagious infectious disease that remains a significant public health concern in the United States despite successful vaccination efforts over decades. This market resolves based on official CDC reported measles case counts through April 30, 2026. The current YES odds at 2% indicate traders assess a very low probability of 2000 confirmed cases being reached by April's end. For perspective, the U.S. has recorded fewer than 100 cases annually in recent years, making a 2000-case threshold an extreme scenario requiring either major breakdown in vaccination coverage, substantial transmission surge among unvaccinated populations, or critical failure in disease surveillance systems. The market's stable 2% price reflects strong consensus that such an outbreak is highly improbable given current vaccination rates, public health infrastructure, and epidemiological conditions. Measles is preventable through vaccination, which remains the primary control measure in the U.S. public health response. Any significant increase in cases would indicate either waning immunity or reduced vaccination uptake, both rare developments in the current landscape.