Will the U.S. see 1,900+ measles cases by May 31, 2026? Current traders estimate 98% likelihood, reflecting ongoing outbreak concerns. Live odds.
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The United States is currently experiencing a measles outbreak, and traders are pricing in a 98% probability that case counts will exceed 1,900 by May 31, 2026 — just over two weeks away. This extremely high odds reflects the current outbreak trajectory and the rapid spread of measles in multiple states. Measles is the most contagious of human viruses, spreading rapidly through unvaccinated populations with reproduction rates of 12-18 secondary infections per case. Given recent epidemiological data, the current threshold of 1,900 cases appears highly attainable. The market's pricing suggests traders believe cases have already approached or substantially progressed toward the threshold as of mid-May, with only official case confirmation timelines remaining variable. CDC reporting procedures create lags between actual infections and official surveillance counts, but the 98% odds indicate near-unanimous trader consensus that the 1,900 threshold will be met by May 31. The outcome depends on CDC case confirmations recorded by the resolution date, with vaccination rates and containment measures serving as secondary factors affecting trajectory.
The United States has experienced periodic measles outbreaks tied to vaccination coverage gaps and population immunity thresholds. Measles is one of the most contagious viral diseases, with an R-value (reproductive number) around 12-18 in unvaccinated populations, meaning each infected person typically infects 12-18 others. The current outbreak appears concentrated in regions with lower vaccination rates, particularly affecting children and young adults. Historical context shows that measles elimination in the U.S. was declared in 2000, but imported cases and local transmission chains periodically establish new transmission clusters. The 2019-2020 measles outbreak in New York involved several hundred confirmed cases before containment measures reduced transmission. The primary drivers pushing this market toward YES resolution include the inherent transmissibility of measles in susceptible populations, ongoing unvaccinated clusters, and the time lag between infection and official case reporting. If cases were already in the range of 1,200-1,500 as of mid-May, the 1,900 threshold becomes highly probable given exponential early-outbreak dynamics. Even at slower transmission rates, two weeks of continued spread could generate 400-700 additional documented cases. School-year factors—unvaccinated children in close contact—and travel during late spring could accelerate spread. The reporting pipeline means confirmed cases are typically documented within 2-4 weeks of symptom onset, so cases emerging in late May would likely be officially counted by May 31 deadlines. Factors that could push the market toward NO are primarily epidemiological interventions: large-scale vaccination campaigns targeting high-risk communities, outbreak containment through case isolation, and reduced transmission as the low-hanging fruit of unvaccinated populations becomes saturated. Public health responses or voluntary isolation due to increased awareness could slow transmission. However, the tight two-week window between May 16 and May 31 limits time for such interventions to meaningfully reduce case counts. The 98% odds reflect trader conviction that measles transmission is already so advanced that hitting 1,900 cases is nearly inevitable. Historically, measles outbreaks in similar U.S. settings have shown rapid acceleration, and the high odds also imply that current confirmed cases are already substantial—likely in the 1,300-1,700 range—leaving only a few hundred additional cases needed to cross the threshold. The market spread here is extremely tight, indicating little disagreement among traders.
The market resolves YES on May 31, 2026, if the CDC surveillance system records at least 1,900 confirmed measles cases in the U.S. The threshold is met by official confirmation date regardless of symptom onset timing.
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