# Above 15 human H5N1 cases in the United States during 2026

> Liquidity-weighted aggregate at 25% across 8 contracts — refreshed 23 min ago.

URL: https://simplefunctions.dev/odds/h5n1count
Updated: 2026-05-28T20:20:07.631Z
Category: general
Status: active
Closes: 2027-01-01

## Headline

- Probability: 25% (liquidity-weighted across 8 contracts)
- Venue: Kalshi (8 contracts)
- 24h volume: $0

## Bound contracts (8)

| Outcome | Price | 24h | Volume | Venue | Slug |
|---|---|---|---|---|---|
| Above 2 | 33¢ | ±0 | $0 | kalshi | /markets/above-2-human-h5n1-cases-in-the-united-states-duri-kalshi-kxh5n1count-27jan01-a2 |
| Above 0 | 44¢ | −1pp | $0 | kalshi | /markets/above-0-human-h5n1-cases-in-the-united-states-duri-kalshi-kxh5n1count-27jan01-a0 |
| Above 1 | 38¢ | −1pp | $0 | kalshi | /markets/above-1-human-h5n1-cases-in-the-united-states-duri-kalshi-kxh5n1count-27jan01-a1 |
| Above 10 | 10¢ | −2pp | $0 | kalshi | /markets/above-10-human-h5n1-cases-in-the-united-states-dur-kalshi-kxh5n1count-27jan01-a10 |
| Above 15 | 8¢ | +1pp | $0 | kalshi | /markets/above-15-human-h5n1-cases-in-the-united-states-dur-kalshi-kxh5n1count-27jan01-a15 |
| Above 3 | 27¢ | +1pp | $0 | kalshi | /markets/above-3-human-h5n1-cases-in-the-united-states-duri-kalshi-kxh5n1count-27jan01-a3 |
| Above 5 | 22¢ | +4pp | $0 | kalshi | /markets/above-5-human-h5n1-cases-in-the-united-states-duri-kalshi-kxh5n1count-27jan01-a5 |
| Above 7 | 16¢ | −2pp | $0 | kalshi | /markets/above-7-human-h5n1-cases-in-the-united-states-duri-kalshi-kxh5n1count-27jan01-a7 |

## 30-day trajectory

| Day | Aggregate |
|---|---|
| 2026-05-14 | 10 |
| 2026-05-21 | 8 |
| 2026-05-27 | 34 |

_9 days of price history captured. Each row is the daily mean of intraday 5-min captures._

## What moved the line

- 2026-05-22 · Above 5 −5pp 23→18¢ · kalshi
- 2026-05-21 · Above 15 +4pp 4→8¢ · kalshi
- 2026-05-27 · Above 5 +4pp 18→22¢ · kalshi

## Analysis

This contract resolves to 'yes' if 15 or more confirmed human H5N1 cases are reported in the United States during 2026. The 15% probability reflects that such an outbreak would represent a significant escalation from recent years. H5N1 cases in the U.S. have been sporadic, with most occurrences limited to agricultural workers with direct animal exposure. The probability depends primarily on two factors: whether the virus continues spreading in U.S. livestock populations (particularly dairy cattle) and whether human-to-animal transmission rates increase or human-to-human transmission emerges. As of mid-2026, actual case data through the year will provide the primary signals for resolution. The contract's value chain shows declining probabilities at higher thresholds—above 10 cases trades at 6% and above 15 at 3%—suggesting market participants view sustained human transmission as unlikely but not impossible. Seasonal patterns and ongoing surveillance will shape how certainty evolves through the remainder of 2026.

### Key factors

- Current confirmed U.S. H5N1 cases in humans through May 2026 compared to historical annual totals (typically 0-3 cases annually before 2024)
- Extent of H5N1 circulation in U.S. livestock, particularly dairy herds, as a prerequisite for human exposures
- Evidence of human-to-human transmission capability, as nearly all historical U.S. cases involved direct animal contact
- Laboratory testing and reporting capacity across states to detect and confirm cases
- Seasonal transmission patterns, particularly during fall/winter months when influenza activity typically increases

## Methodology

Probability is **liquidity-weighted** across all bound Kalshi/Polymarket contracts: Σ(price × volume) ÷ Σ(volume). 30-day trajectory uses the daily mean of intraday 5-min captures. 24h delta = today's mean − yesterday's mean. Movement events are ≥3pp daily moves in the last 7 days.

## How to use this data

- HTML: https://simplefunctions.dev/odds/h5n1count
- JSON: https://simplefunctions.dev/api/public/odds?slug=h5n1count

## License

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