The Prediction Markets

How many West Nile neuroinvasive disease cases will be reported among New York City residents in 2026?

Closes
Mar 31, 2027, in 5 months
Traded
$66K
Venues
Polymarket
Prices updated
4 min ago
Share

What the markets expect

20 to 34 90%

Next is 35 to 49 at 9.4%. Only Polymarket lists this market, so there is no second price to compare.

20 to 34 90%35 to 49 9.4%50 or more 0.5%Fewer than 20 0.1%

Odds by venue

Fair chance strips out each venue’s built-in margin (its prices add up to more than 100%), then blends the venues by how much has traded there, so the outcomes add up to 100%. Best Yes price is the cheapest ask across venues, and the payout is what a winning $100 stake returns before fees. Open a row for each venue’s contract name, bid and ask, and how closely their rules match.

Prices come from our regular polls of each venue, the oldest 4 min ago. Ages are as of when this page was built.

  • Polymarket
20 to 34
90%
Polymarket 90.6%(90% fair)polled, 4 min agoBest Yes 90.8¢ on Polymarket, $100 pays $110 (1.10x)
Polymarket
Contract
20 to 34
Last price
90.6%
Fair, margin removed
90%
As of
Polled 4 min ago
Buy Yes
90.8¢
Sell Yes
90.4¢
$100 on Yes pays
$110 (1.10x)
Volume
$26K
Trade this on Polymarket
35 to 49
9.4%
Polymarket 9.5%polled, 4 min agoBest Yes 10¢ on Polymarket, $100 pays $1,000 (10.0x)
Polymarket
Contract
35 to 49
Last price
9.5%
As of
Polled 4 min ago
Buy Yes
10¢
Sell Yes
9¢
$100 on Yes pays
$1,000 (10.0x)
Volume
$16K
Trade this on Polymarket
50 or more
0.5%
Polymarket 0.5%polled, 4 min agoBest Yes 0.6¢ on Polymarket, $100 pays $16,667 (167x)
Polymarket
Contract
50 or more
Last price
0.5%
As of
Polled 4 min ago
Buy Yes
0.6¢
Sell Yes
0.4¢
$100 on Yes pays
$16,667 (167x)
Volume
$14K
Trade this on Polymarket
Fewer than 20
0.1%
Polymarket 0.1%polled, 4 min agoBest Yes 0.1¢ on Polymarket, $100 pays $100,000 (1000x)
Polymarket
Contract
Fewer than 20
Last price
0.1%
As of
Polled 4 min ago
Buy Yes
0.1¢
Sell Yes
—
$100 on Yes pays
$100,000 (1000x)
Volume
$10K
Trade this on Polymarket

Who resolves this market

Polymarket
Polymarket resolves via:
UMA optimistic oracle, source: nyc.gov

How the odds have moved

The top 3 outcomes on both venues, with the consensus between them. Hover for exact values.

  • 20 to 34
  • 35 to 49
  • 50 or more

Order books

Each venue’s resting orders for the selected outcome’s Yes contract, side by side. Top of book streams live; depth refreshes every 15 seconds.

Polymarket

Open on Polymarket ↗

Top of book

Connecting
Best bid
—
Spread
—
Best ask
—

Waiting for the first live quote…

Depth · top 8 levels

Loading snapshot…

Recent trades

Loading…

What your stake buys

Enter a stake to see where it buys the most after fees, using each venue’s live order book.

$
Buy

Loading both order books…

Cover all 4 outcomes across venues

Loading every outcome’s book…

Buys at the asks resting now (taker orders), cheapest after fees first, from order-book snapshots up to 15 seconds old. Fees: Kalshi 0.07 × price × (1 − price) per share, rounded up to the cent; Polymarket 0.05 × price × (1 − price) per share (other / general rate). Fee calculator. Estimates only, not advice.

About this market

Live prediction market odds for "How many West Nile neuroinvasive disease cases will be reported among New York City residents in 2026?". 20 to 34 leads at 90%. Next is 35 to 49 at 9.4%. $66K has traded across 4 outcomes on Polymarket. The market is expected to resolve by Mar 31, 2027.

This market resolves based on the total number of West Nile neuroinvasive disease cases (encephalitis, meningitis, and acute flaccid paralysis) reported among New York City residents in 2026, as published by the New York City Department of Health and Mental Hygiene on its West Nile Virus Reports page at nyc.gov/site/doh/health/health-topics/west-nile-virus-reports.page. Cases are counted as whole numbers, so each outcome covers a distinct range with no overlap or gap. The 2026 count shown on the source as of January 1, 2027 is the starting figure. If the DOHMH publishes or revises the 2026 count on or after January 1, 2027, this market will resolve based on the count shown on the source at 11:59 PM ET on the 14th day after the first such update, or on March 31, 2027, 11:59 PM ET, whichever comes first. If no such update occurs, this market will resolve on March 31, 2027, 11:59 PM ET, based on the 2026 count shown on the source at that time. If no 2026 count has been published on the source by March 31, 2027, 11:59 PM ET, this market will resolve based on the sum of 2026 West Nile neuroinvasive disease case counts reported by CDC ArboNET for the five New York City counties (Bronx, Kings, New York, Queens, and Richmond). Revisions published after this market resolves will not be considered. If the DOHMH changes its reporting format or URL structure, the closest equivalent NYC Health Department publication of 2026 West Nile neuroinvasive case data will be used.

Questions

What does the consensus price mean?

It is the price of a Yes contract that pays $1 if the outcome happens. A 14¢ price means traders put the chance near 14%. Where two venues list the same outcome, we blend their last prices, weighting the venue with more trading volume more heavily (neither counts for less than a quarter). When only one outcome can win, each venue’s prices add up to a little over 100% (its margin); the fair chance removes that margin so the outcomes add up to exactly 100%.

How is the payout worked out?

A Yes contract pays $1 if it wins, so at the best ask a $100 stake buys 100 ÷ ask contracts. At 18¢ that is about 555 contracts, paying $556 (5.56x) if Yes happens. Venue fees and price slippage on larger orders are not included.

Why do the venues show different prices?

Each venue has its own traders, fees and order book. Contracts can also settle on slightly different terms, which is why each row lists how closely the rules match.

Is a price gap an arbitrage?

Only when you can buy Yes on one venue below what someone pays for Yes on the other, after fees, and both contracts settle the same way. We show the executable bid and ask so you can check.

How fresh are these prices?

Venue prices refresh every few minutes, and the order book and live quotes stream continuously. Each venue’s card shows when we last observed it.

More other markets

See all other markets