Tools chosen: kalshi_direct kalshi_related polymarket_related claude_news gdelt_news wikipedia code_execution

Sub-questions (Fermi decomposition)

Planner reasoning

This hinges on wild poliovirus type 1 case counts in Pakistan and Afghanistan; 2024 and 2025 both had dozens of cases, so only 2026-2029 remain as chances for a zero-case calendar year. Key research is GPEI/WHO surveillance data, eradication timeline targets, and the current Kalshi price as the anchor.

# Current state As of mid-2026 (latest GDELT news through 2026-07-31), wild poliovirus (WPV1) transmission continues uninterrupted in the Afghanistan-Pakistan endemic bloc — 2026 already has confirmed cases (Afghanistan: 6 cases by June 2026; Pakistan: ~30+ cases reported since May 2026), meaning 2026 is already disqualified as the "zero year." Resolution requires any single calendar year 2024-2029 with zero globally reported WPV1 cases; with 2024 (~99 cases) and 2025 (~36-38 cases) also non-zero, only 2027, 2028, or 2029 remain eligible. Kalshi prices YES at 9.4%. # Event Will there be at least one year between 2024-2029 with zero reported wild poliovirus (WPV1) cases globally? (KXPOLIOELIM-30) # Outcomes to forecast - Yes (a zero-WPV1 year occurs before 2030) - No (no zero-WPV1 year occurs before 2030) # Kalshi market anchor **YES currently priced at 9.40%** (KXPOLIOELIM-30). 7-day change: -0.60%; 30-day change: -1.00%. Range over ~99 days of trading: 3.00%-10.70%. Average daily volume ~166-276 contracts — thin but persistent trading, price has drifted slightly downward recently, suggesting market sees eradication timeline slipping, not accelerating. [kalshi_direct] # Sub-question answers 1. **Case counts 2021-2025**: 2021: 6 (historic low, Pakistan-only per Wikipedia); 2022: ~30 (compiled); 2023: ~12; 2024: 99 global (74 Pakistan + 25 Afghanistan, per WHO IHR/claude_news); 2025: ~36-38 global (24-28 Pakistan, 4-9 Afghanistan) — a sharp decline from 2024 but still far above zero. [claude_news, Wikipedia] 2. **GPEI target**: Official target is interruption/certification of WPV1 by **2027**, cVDPV2 by 2029. This target has already been pushed back multiple times historically (originals were 2000, then repeated revisions); current 2027 target is the latest iteration. [WHO IHR statement, claude_news] 3. **Environmental surveillance**: Positive samples fell sharply — 741 positive samples in all of 2024 (628 Pakistan) vs. only 80 by mid-2025 (71 Pakistan) — suggesting geographic narrowing, but Pakistan's July 2026 environmental positivity rate was still 13.1%, and a border-closure-driven surveillance backlog (since Oct 2025) may be masking true circulation. [claude_news, GDELT/dunyanews] 4. **Constraints**: Taliban restrictions on house-to-house/female vaccinators persist (CDC MMWR); GPEI 2026 budget cut ~30% ($786M vs $1.1B in 2025, $1.7B funding gap through 2029), partly offset by a $1.9B Dec-2025 pledge; attacks on vaccination workers continue in Pakistan (2026 reports of worker killings); Afghanistan-Pakistan border closures (since Oct 2025) disrupting surveillance sample transport. [claude_news, GDELT] 5. **Base rate/compounded probability**: Negative-binomial fit to 2019-2025 case data (heavily overdispersed) implies annual P(zero)≈0.8-0.9%, compounding to only ~3.2-3.6% over 4 years — but judgmental/declining-hazard scenarios (assuming accelerating eradication progress) push compounded probability to ~20-35%. [code_execution] 6. **Kalshi vs. base rate**: Kalshi's 9.4% sits between the purely statistical NB-model estimate (~3-4%) and the more optimistic declining-hazard scenarios (~25-35%), suggesting the market is pricing meaningfully below optimistic eradication narratives but above pure historical extrapolation. # Key facts (high-confidence, factual) 1. [claude_news/WHO] 2024 global WPV1 total: 99 cases (Afghanistan 25, Pakistan 74). 2. [claude_news] 2025 total: ~36-38 cases (declining from 2024 but nonzero). 3. [GDELT, 2026-06-18] Afghanistan already recorded 6 WPV1 cases by June 2026; Pakistan recorded new cases through July 2026 — 2026 is confirmed non-zero. 4. [WHO] GPEI's official interruption target is 2027; Afghanistan and Pakistan are treated as one epidemiological transmission bloc. 5. [claude_news] GPEI 2026 budget cut ~30% to $786M; $1.7B funding gap through 2029; $1.9B pledged Dec 2025. 6. [Wikipedia] Historic case low was 6 (Pakistan, 2021); WPV1 has never reached zero globally in the modern surveillance era. # Cross-market signals - Kalshi related: Only this market itself found in series scan (9.40% YES), no distinct comparator market. - Polymarket: No matching markets found (0/100 scanned). - Sportsbook implied: N/A (not applicable to this event type). # Analyst opinions and speculation - WHO polio director (Ahmed): "Eradication remains feasible and is doable" — official optimism, but qualitative, not quantitative. [Yahoo/AP] - code_execution synthesis: pure statistical extrapolation gives ~3-4%, but judgmental adjustment for accelerating eradication effort could push probability to 20-35%; author frames 9-15% as a "conservative" plausible range and up to 48% under aggressive-improvement assumptions. # Directional lean per outcome - **Yes**: Supported by steep 2024→2025 case decline (99→~37), narrowing environmental sample positivity, new $1.9B funding pledge, and 3 remaining eligible years (2027-2029) with GPEI target aligned to 2027. Opposed by 2026 already confirmed non-zero, persistent Taliban restrictions, surveillance backlog/border closures obscuring true circulation, and no zero year ever achieved historically. - **No**: Supported by strong historical base rate (never zero in decades of trying), overdispersed/volatile case counts, 30% funding cut, security/access constraints in both countries, and Kalshi's own low 9.4% pricing. This is the stronger lean. # Gaps / unknowns - No confirmed case data past July 2026; unclear full-year 2026 total (already nonzero, but magnitude uncertain). - Surveillance backlog since Oct 2025 (border closures) creates uncertainty about true undetected circulation — could mean current low counts understate transmission. - No data on cVDPV lineage extending eradication timeline; this market only concerns WPV1, not cVDPV. # Calibration anchors - Kalshi current YES price: **9.40%** (anchor). - Historical precedent: Zero WPV1 years have never occurred in the surveillance era (lowest was 6 cases in 2021); repeated GPEI target slippage (from ~2000 to 2027 and beyond) supports skepticism toward optimistic scenarios. - Statistical (NB) model: ~3-4% compounded probability; judgmental/declining-hazard models: ~20-35%. Kalshi's 9.4% sits near the lower-middle of this range, reasonably calibrated but slightly above pure historical extrapolation.

1. Both forecasts cluster tightly around Kalshi's 9.4% (7.0% and 10.0%) without independently stress-testing the "reporting/confirmation lag" issue—since a "zero year" for 2029 would need to be confirmed only after 2030, and even 2028's full case count may not be finalized by market close, both should have flagged resolution-source ambiguity (WHO retrospective revisions can add cases months later) as a reason to discount YES further, not just marginally. 2. Neither forecast explicitly grapples with the surveillance-backlog caveat: the brief notes "a border-closure-driven surveillance backlog... may be masking true circulation," meaning even a reported low-case year could later be revised upward or reflect undetected transmission—this asymmetry (undercounting risk) should bias both estimates toward No more than they currently do. 3. Forecast 1's citation of "recent price drift downward" as justification for going below Kalshi (7.0% vs 9.4%) is a reasonable read of momentum, but neither forecaster considers that thin volume (166-276 contracts/day) makes the price drift statistically weak evidence, so leaning on it as a meaningful signal is overconfident given the market's illiquidity. 4. Neither model addresses the compounding/independence assumption embedded in the NB base rate (~3-4%): case counts across years are likely positively correlated (funding cuts and Taliban restrictions persist multi-year), so treating 2027-2029 as quasi-independent draws overstates the "3 chances" framing—true probability of any single zero year may be lower than naive compounding suggests, an issue neither forecaster interrogates. 5. Both forecasts underweight the scenario where cVDPV lineage confusion or reclassification affects "WPV1" case attribution—the brief notes "this market only concerns WPV1, not cVDPV," but doesn't verify how ambiguous cases are counted, a resolution-criteria risk neither forecaster raises despite its potential to swing a borderline near-zero year. 6. Neither forecast substantially engages with the optimistic tail scenario (WHO's "eradication remains feasible" framing plus the $1.9B pledge partially offsetting cuts) as a real possibility beyond citing it dismissively—both land near or below the anchor, but if 2027 (the official GPEI target year) genuinely sees a steep proximity-to-zero push, the judgmental 20-35% scenarios deserve more weight than a 7-10% central estimate implies.

7% (medium confidence)

Yes: 7% No: 93%

With 2024 (99 cases), 2025 (~37), and 2026 (already confirmed non-zero by mid-year) all disqualified, only 2027-2029 remain, and going from ~30+ cases in a year to a full calendar year of zero within 1-3 years has no historical precedent (record low was 6 in 2021). Structural headwinds — the ~30% GPEI budget cut, $1.7B gap, Taliban restrictions on house-to-house and female vaccinators, worker attacks, and the Oct-2025 border-closure surveillance backlog — are persistent and positively correlated across years, so the naive 'three independent chances' framing overstates YES. The critique's points about retrospective WHO case revisions and the resolution/confirmation lag (a 2029 zero year could not be verified by the 2030-01-01 close) are asymmetric against YES and justify sitting modestly below the 9.4% Kalshi anchor, though thin volume means the recent downward drift is weak evidence on its own. I retain some weight for the optimistic declining-hazard scenario (steep 99→37 decline, narrowing environmental positivity, $1.9B pledge, GPEI's 2027 target), which prevents going down to the pure statistical ~3-4%.

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