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Trade: Confirmed case of Hantavirus in US by May 15?

82% YES 18% NO

Opened · Settles · 40 comments

Resolution criteria on PolyGram: This market will resolve to "Yes" if there is a confirmed case of Hantavirus in the territory of the United States of America reported between market creation and May 15, 2026, 11:59 PM ET. Otherwise, this market will resolve to "No". Any laboratory-confirmed hantavirus infection identified within U.S. territory will qualify, regardless of where exposure or symptom onset occurred. The primary resolution source for this market will be official government information (e.g., the CDC); however, an overwhelming consensus of credible reporting will also suffice.

PolyGram is an on-chain prediction market where you trade YES or NO outcome shares with real USDC on Polygon. For this market, buy YES if you believe the event will happen, or NO if you think it won't. Your maximum loss is your stake — winning shares pay $1.00 each at resolution. Unlike sportsbooks, there is no house edge: prices are set by supply and demand from other traders and reflect the crowd's real-time probability.

Liquidity
$17K
Total Volume
$211K
24h Volume
$109K
Open Interest
$66K
Trade this market on PolyGram →

Market outcomes

Confirmed case of Hantavirus in US by May 15? 82% YES18% NO

Market context

Hantavirus detection in the United States represents a genuine public health surveillance outcome. The virus, primarily transmitted through contact with infected rodent droppings or urine, causes hantavirus pulmonary syndrome (HPS), a severe respiratory illness with significant mortality rates. Cases occur sporadically across North America, typically linked to environmental exposure in rural or semi-rural settings. The current 44% implied probability on Polymarket's order book reflects meaningful uncertainty about whether at least one confirmed case will be identified and reported by mid-May 2026—a roughly 13-month window.

Historical context shapes the baseline expectation. The United States has documented confirmed hantavirus cases nearly every year since the virus was first identified in 1993, with annual case counts typically ranging from zero to a handful. Between 2015 and 2023, the CDC recorded confirmed cases in most years, though numbers remained low. This consistent but infrequent detection pattern underpins the moderate probability currently priced. The virus circulates in rodent populations across much of the country, making complete absence unlikely over a 13-month period, yet cases remain rare enough that non-occurrence remains plausible.

Traders should monitor CDC surveillance reports and official health department announcements, which represent the primary resolution pathway. Seasonal rodent activity typically peaks in autumn and winter months, potentially increasing exposure risk during those periods. Any cluster of respiratory illness cases or unusual rodent activity reports in endemic regions could signal heightened detection likelihood. The market's probability reflects genuine epidemiological uncertainty rather than extreme tail-risk pricing.

How this market resolves

Resolution is handled by the UMA optimistic oracle on Polygon. A proposer submits the outcome, a two-hour dispute window opens, and if no one stakes a counter-claim the payout is final. Contested outcomes escalate to UMA token-holder voting. Payouts clear in USDC to the winning side.

How to trade this market step by step

The mechanics for trading "Confirmed case of Hantavirus in US by May 15?" are the same as any other PolyGram event contract. Each YES share resolves to $1 if the event happens, or $0 if it doesn't. The current price between 0¢ and 100¢ is the market's probability estimate, set live by the order book.

  1. Sign in on polygram.ink with your email — no full KYC under $1,500 lifetime trading volume.
  2. Deposit USDC on Polygon (lowest fees, ~$0.01 per transaction) or Ethereum. Funds credit after 12 confirmations.
  3. Pick a side. Buy YES if you believe the event will happen; buy NO if you think it won't. The current YES price reflects the market's collective probability.
  4. Size your position. If you stake 100 USDC at 82% YES, you'll receive shares that pay $122 if YES resolves true — a 22% gross return. If NO resolves, your shares are worth $0.
  5. Set risk controls (optional). Stop-loss, take-profit, and limit-order types all supported. Use the trade ticket's slippage box to cap your maximum entry price.
  6. Wait for resolution. When the event resolves on-chain via the UMA optimistic oracle, the winning side settles to 100¢ automatically and USDC hits your balance within seconds. Withdrawable to any wallet you control.

How active is this market?

$211K in lifetime turnover and $17K of resting liquidity puts this market in the top 10% by volume for weather contracts on PolyGram. Order-book depth is modest — expect a couple of cents of slippage on $1k+ trades.

Last 24 hours alone saw $109K in turnover, well above the lifetime daily-average for this market — a clear sign of news catalysing trader activity right now.

The market has been open for under a month — fresh enough that information asymmetry remains a real factor.

Higher-volume markets tend to have tighter spreads and faster price discovery — meaning the displayed YES/NO percentages are more likely to reflect the true crowd-implied probability rather than a single trader's directional view.

Key terms

YES / NO share
A binary outcome token that pays $1.00 if the underlying claim resolves true (YES) or false (NO), and $0 otherwise. The market price between 0¢ and 100¢ is the implied probability.
CLOB
Central limit order book. The matching engine that pairs YES buyers with NO buyers (effectively the same trade). Polymarket's CLOB on Polygon executes trades on-chain via the conditional-tokens framework.
Liquidity
USDC capital sitting in resting limit orders inside the order book. Deeper liquidity means smaller slippage on large trades and a tighter bid-ask spread.
UMA optimistic oracle
The on-chain dispute system that settles each Polymarket market. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution.
Slippage
The difference between the displayed mid-price and your fill price. Affects market orders most; limit orders avoid slippage but may take time to fill.
Conditional token
ERC-1155 outcome share issued by Gnosis Conditional Tokens on Polygon. The token type that resolves to $1.00 or $0.00 at settlement.

See the full prediction-market glossary →

Frequently asked questions

What is the current probability for "Confirmed case of Hantavirus in US by May 15?"?

As of today, traders on Polymarket price this outcome at 82%. The number updates continuously as the order book clears. PolyGram mirrors the same live odds with locale-aware formatting and USDC settlement.

How does this market resolve?

Resolution is handled by the UMA optimistic oracle on Polygon. A proposer submits the outcome, a 2-hour dispute window opens, and if uncontested the payout is final. Contested outcomes escalate to UMA token holders.

When does this market close?

This prediction market is scheduled to close on 15 May 2026. After the resolving event occurs, settlement typically clears within 24 hours once the UMA optimistic oracle confirms the outcome. All payouts are in USDC on the Polygon network.

How can I trade on "Confirmed case of Hantavirus in US by May 15?"?

To trade on this prediction market, create a free PolyGram account at polygram.ink, deposit USDC via Polygon, and place a YES or NO order on the outcome you believe in. You can learn more on our how-it-works page. Your maximum loss is limited to your stake — there is no leverage or margin.

What happens when the market resolves?

When the outcome is determined, winning YES shares pay out $1.00 each in USDC, while losing shares pay $0. Settlement is handled by the UMA optimistic oracle on Polygon — a proposer submits the result, a two-hour dispute window opens, and if uncontested, payouts are distributed automatically. You can withdraw your winnings to any Polygon wallet.

Risk and regulatory note

Prediction-market positions can lose 100% of staked capital. Outcomes are uncertain by definition — historical accuracy of crowd-implied probabilities is high in aggregate but not for any single market. PolyGram does not provide investment advice. Trade only with capital you can afford to lose.

Regulatory status varies by jurisdiction. Germany, the United States, and most EU countries treat Polymarket-style event contracts under one of three frameworks: financial derivative, gambling product, or unregulated novel asset. Consult local counsel before trading.

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