29% — Measles cases in U.S. by April 30?: 1800
Kalshi 29% · 6 contracts · $474 volume · medium confidence
Updated 2026-06-30 04:27:04 UTC

Why this matters:
This market estimates a 29% probability that the U.S. will record at least 1,800 measles cases by April 30, 2026. The probability reflects the balance between factors that could drive case increases (vaccination coverage gaps, imported cases from ongoing global outbreaks) and those limiting spread (existing immunity levels, public health response capacity). The primary uncertainty centers on vaccination rates among susceptible populations and whether any outbreaks accelerate in the coming months. The CDC's weekly case reporting provides the most direct evidence for resolution, with the April 30 deadline now less than one year away. Current measles activity levels relative to historical baselines will be critical—the U.S. reported 127 cases in 2024, so reaching 1,800 would require a substantial increase from recent trends.

Key factors:
- U.S. measles vaccination coverage rates and immunity levels in susceptible age groups
- Number of measles cases imported or detected in early 2026 relative to historical seasonal patterns
- Vaccination uptake trends following any detected outbreaks or public health messaging campaigns
- Global measles activity and international travel patterns affecting case importation risk
- Public health response effectiveness and outbreak containment speed in any identified clusters

Contracts:
- Will there be more than 8000 measles cases in 2026?: Above 8000 — 10¢ Kalshi $247 (weight 52%)
- Will there be more than 4000 measles cases in 2026?: Above 4000 — 31¢ Kalshi $139 (weight 29%)
- Will there be more than 10000 measles cases in 2026?: Above 10000 — 6¢ Kalshi $85 (weight 18%)
- Will there be more than 6000 measles cases in 2026?: Above 6000 — 12¢ Kalshi $3 (weight 1%)
- What will the average number of measles cases be during the Trump Administration?: At least 5000 — 30¢ Kalshi $0 (weight 0%)
- What will the average number of measles cases be during the Trump Administration?: At least 2000 — 86¢ Kalshi $0 (weight 0%)

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## Methodology

SimpleFunctions aggregates live YES-side prices from Kalshi and Polymarket contracts bound to this question. For binary topics the headline is the liquidity-weighted mid-price (weight = log(1 + 24h volume) × freshness, where freshness is 1.0 if updated <24h, 0.7 if <7d, 0.4 otherwise). For multi-outcome (winner-take-all) topics the headline is the current leader's price — disjoint outcomes are never arithmetically averaged. Snapshots refresh every 5 minutes during market hours.

## SF Signal

- SF Index, regime, and 30d Brier calibration are computed separately and surfaced at https://simplefunctions.dev/admin/calibration.
- No SimpleFunctions index / regime / calibration signal is bound to this topic yet — the headline above is market-derived only.

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*Last verified: 2026-06-30T04:20:50.428Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "29% per prediction markets (SimpleFunctions, June 2026)"
Canonical: https://simplefunctions.dev/answer/measles-cases-us-april-30
Full data: https://simplefunctions.dev/api/public/query?q=Measles%20cases%20in%20U.S.%20by%20April%2030%3F%3A%201800
Provider: SimpleFunctions — https://simplefunctions.dev