Above 0 human H5N1 cases in the United States during 2026

Bottom line up front: CDC's count rose from 71 to 72 between the cached copy (about early March 2026) and its Oct 15, 2026 page update. I could not find which case is the 72nd or when it was reported. If it was reported in 2026, the question has already resolved Yes. - [2026-10-15] CDC's "A(H5) Bird Flu: Current Situation" page was updated Oct 15, 2026. Its footnote says there are 72 reported US human A(H5) cases since Feb 2024: 7 found through national flu surveillance and 65 through human monitoring. An earlier cached copy of the same page, indexed about 224 days ago (roughly early March 2026), said 71 (7 surveillance, 64 monitoring). The case table did not load in either fetch, so I could not see the 72nd case's date, state or exposure. https://www.cdc.gov/bird-flu/situation-summary/index.html - [2025-11-15] WHO called the Washington H5N5 case the 71st US case since early 2024 and the first since Feb 2025. It was notified on Nov 15, 2025. CDC sequencing on Nov 20, 2025 verified the virus as H5N5, not H5N1. It was fatal and was reported in 2025. https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON590 - [2026-05-07] The MMWR report on the fatal Washington H5N5 case (Nov 2025) found about 135 exposed people and no additional cases. https://www.cdc.gov/mmwr/volumes/75/wr/mm7517a2.htm - [2026-07-30] A Congressional Research Service report said CDC counted 71 US cases and 2 deaths from 2024 through July 30, 2026. This suggests the 72nd case was added after that date, but that is an inference. https://www.congress.gov/crs-product/R48580 - [2026-10-02] CDC's surveillance page (data through Sep 26, 2026) says flu surveillance shows no unusual influenza activity in people, including A(H5). Between Sep 28, 2025 and Sep 26, 2026, at least 5,000 people were monitored and at least 158 were tested. https://www.cdc.gov/bird-flu/h5-monitoring/index.html - [2026-10-08] FluView Week 39 (ending Oct 3, published about Oct 9) reported no new confirmed novel influenza A human infections that week. https://www.cdc.gov/fluview/surveillance/2026-week-39.html - [2026-10-16] FluView Week 40 (ending Oct 10) was published. Its novel-influenza section was cut from my fetch, so I could not read it. https://www.cdc.gov/fluview/surveillance/2026-week-40.html - [2026-10-08] Washington State announced its first H5N1 detection in dairy cattle, on two Yakima County farms. Officials are monitoring exposed farmworkers. This is the 20th state with infected cattle, per one report. https://afludiary.blogspot.com/2026/10/wsda-washington-confirms-first.html - [2026-10-12] CIDRAP says 93 dairy herds have been confirmed in 2026, against 917 in 2024 and 171 in 2025. Four herds, including some in Kansas and Texas, were detected in the past 30 days. https://www.cidrap.umn.edu/avian-influenza-bird-flu/washington-state-confirms-first-h5n1-avian-flu-detection-dairy-cattle - [2026-10-13] Puerto Rico confirmed avian influenza on two private properties (Cabo Rojo and Lajas). 27 people are being monitored and none had symptoms as of Oct 13. This is a US territory, and the report said CDC still listed 71 cases at the time. https://www.riotimesonline.com/puerto-rico-bird-flu-quarantine-2026/ - [2026-10-16] A Substack roundup lists Washington cattle spread as a watchlist item. It reports no new US human cases, only Cambodia and Bangladesh H5N1 cases elsewhere. This is a secondary source. https://josepheastman.substack.com/p/pathogen-report-10-16-2026 - [2026-06-26] CDC's global summary covers Aug 2025 to Jun 2026. International cases came mainly from Cambodia and Bangladesh. https://flutrackers.com/threads/cdc-global-summary-of-human-cases-of-h5n1-bird-flu-from-august-2025-to-june-2026.1037479/ BOTTOM LINE: As of Oct 17, 2026, I found no confirmed 2026 US human H5N1 case reported by news or by FluView Week 39. CDC's total moving from 71 to 72 is unexplained and is the key thing to check, because a 2026 H5N1 case would settle the question as Yes. If the 72nd case was reported in 2026, the question has resolved Yes. If it was backdated to 2025 or was not H5N1, the answer depends on new cases before the Jan 8 cutoff. Washington's new dairy outbreak and the fall poultry/migration season add some risk of one. NOT FOUND: The identity, date, state, subtype and exposure of CDC's 72nd case. The content of the CDC case table. The novel-influenza section of FluView Week 40. Any state health department announcement of a 2026 US human H5 case.

- [2026-10-16] CIDRAP's avian flu page lists a "Quick takes" item with the headline "US human avian flu case". It says the H5N1 case is in a Yakima County, Washington resident who was exposed to infected dairy cows . I read only the index listing, not the full article, so I have no case date, confirmation status (confirmed or probable) or onset date. https://www.cidrap.umn.edu/avian-influenza-bird-flu - [2026-10-16] Health and Me, in a piece dated Oct 16, 2026, reports a Washington human case. It follows H5N1 detection in dairy cattle on two Yakima County farms, and the resident was exposed to infected animals. The farms are quarantined. This is a secondary source. https://www.healthandme.com/health-news/washington-reports-human-bird-flu-case-after-dairy-cattle-exposure-should-you-be-worried-article-156352801 - [2026-10-15] The CDC situation page, dated Oct 15, 2026, says 72 total human A(H5) cases have been reported in the US since February 2024. Of these, 7 were found through national flu surveillance and 65 through human monitoring. Earlier 2026 sources (CRS, the AAO, a viruswatcher page) all gave 71, so the count appears to have risen by one. The page does not show which case is the 72nd or its date. CDC says it reports additional cases on that page and in FluView. https://www.cdc.gov/bird-flu/situation-summary/index.html - [2026-09-08] The CRS report (R48580) says 71 confirmed cases and 2 deaths since 2024, with the table running through July 30, 2026. That table lists no 2026 cases, and the report shows no increase in 2026 up to that point. Probable cases are counted separately (7). https://www.congress.gov/crs-product/R48580 - [2025-11-14] Washington state confirmed the first US human case since February 2025. It was H5N5, not H5N1, in a Grays Harbor County resident. It was the first human H5N5 infection ever. This is relevant because a strain mismatch could matter for this contract's "H5N1" wording. https://www.cidrap.umn.edu/avian-influenza-bird-flu/first-ever-human-case-h5n5-avian-flu-confirmed-washington-state - [2025-08-04] Base rate by year: CDC counted 70 US cases in 2024 and early 2025. Only 3 US cases occurred in 2025 through early August, and none were reported after mid-February 2025 until the Nov 2025 H5N5 case. The gap between reported cases ran about 9 months. https://www.cdc.gov/bird-flu/spotlights/h5n1-summary-08042025.html - [2026-09-26] CDC monitoring data: at least 5,000 people monitored and at least 158 tested for novel influenza A between Sep 28, 2025 and Sep 26, 2026. Testing volume is low compared with 2024. CDC says its flu surveillance shows no unusual flu activity in people. https://www.cdc.gov/bird-flu/h5-monitoring/index.html - [2026-10-15] CIDRAP headlined an "avian flu uptick in US" on Oct 15, 2026, the day before the Yakima case item. This suggests animal-side activity is rising in the autumn migration season. The item is in the index listing only, and I did not read it. https://www.cidrap.umn.edu/avian-influenza-bird-flu - [2026-10-07] Reference class, annual US human H5N1 cases: about 66 in 2024, a few in early 2025 (3 in 2025 through August, plus the H5N5 case), and apparently none or very few from Jan to Sep 2026. Autumn and winter poultry and dairy outbreaks have historically driven case clusters. Globally, only 12 non-US H5N1 cases were reported from Aug 2025 to Jun 2026. https://www.cdc.gov/bird-flu/spotlights/global-summary-06262026.html - [2026-10-14] I found no formal forecasts, expert estimates or sibling-market odds for 2026 US human cases. I did not search for this contract's own price, as instructed. BOTTOM LINE: Several signals suggest a US human case was reported on about Oct 16, 2026: a CIDRAP headline, a secondary article, and CDC's count rising from 71 to 72. If it is a confirmed H5N1 case with a 2026 report date, the outside view points to YES. The base rate for any single year is otherwise mixed, since 2025 had only a few cases, so the forecaster should verify the case's status, subtype (H5N1 vs H5N5) and date. NOT FOUND: the full text of the Yakima County case article, the Washington DOH or CDC announcement with the date and confirmation status, whether any case occurred earlier in 2026, any expert or market forecasts, and the Kalshi source-agency hierarchy.

YES means: the number of human H5N1 cases reported in the US during 2026 is above 0, so at least one case is reported with a 2026 date by the Jan 8, 2027 cutoff. - [2026-10-15] The Yakima Health District, working with Washington DOH, announced a "confirmed case of avian influenza" in a Yakima County resident. The resident was exposed to infected dairy cattle at a Yakima County dairy. The person is not severely ill, was not hospitalized and is isolating at home. This is the primary release, which I read in full on Avian Flu Diary. It names the dairy-linked H5N1 outbreak as context but does not itself state the subtype. https://afludiary.blogspot.com/ - [2026-10-16] CIDRAP's Quick Takes search snippet says "Yakima County, Washington, officials reported an H5N1 highly pathogenic avian influenza (HPAI) infection in a resident exposed to infected dairy cows." The snippet says the case came a week after the state's first dairy detection. CIDRAP's page returned HTTP 403 when I fetched it, so I am relying on the search snippet. https://www.cidrap.umn.edu/avian-influenza-bird-flu/quick-takes-us-human-avian-flu-case-dengue-florida-plague-madagascar-mers - [2026-10-16] Feed Strategy reports the Yakima Health District announced the case on Oct 15. It says the resident tested positive for avian influenza after exposure to H5N1-affected herds. https://www.feedstrategy.com/animal-health-veterinary/livestock-poultry-diseases/avian-influenza/news/15837700/yakima-county-washington-resident-contracts-h5n1-after-exposure-to-affected-cattle - [2026-10-16] Poultrymed says the infection was confirmed by the Yakima Health District and Washington DOH. It describes the person as an agricultural worker with mild symptoms who is recovering at home. https://www.poultrymed.com/ID-Eng-Yak161026 - [2026-10-16] Apple Valley News Now, a local outlet, independently reports the positive test. It says the health district is contacting close contacts. https://www.applevalleynewsnow.com/news/yakima-county-resident-tests-positive-for-avian-influenza-after-exposure-to-infected-dairy-cattle/article_0570354a-58e7-4285-82aa-afebf4814a50.html - [2026-10-08] The case is a worker-exposure case. The dairy detection was confirmed Oct 8, and officials stated then that there were no human cases. The case therefore appeared in the week after, which fits an onset in October 2026 and makes a 2025 backdating implausible. https://www.yakimaherald.com/news/local/avian-influenza-detected-at-two-yakima-county-dairy-farms/article_7dc797b5-e06a-487e-93b2-c403a1258a7b.html - [2026-10-15] Mechanism for CDC counting: CDC's page update on Oct 15 moved the count from 71 to 72, which coincides with this announcement. The most likely explanation is that CDC added the Washington case. This is an inference, because the case table did not load. See the colleague reports for the count. - [2026-10-08] The case occurred at a dairy that was newly infected. Cattle onset was about a week before Oct 8, with sick cows and reduced milk yield. Two infected herds, ongoing worker contact and testing of exposed people leave room for further 2026 cases. https://hoodline.com/2026/10/bird-flu-hits-two-yakima-county-dairy-herds-washington-s-first-cattle-cases/ **Most likely path to YES:** the Oct 15 Yakima case is already reported. It needs only to be treated as H5N1 and counted as 2026 by the resolving source (CDC's situation page or FluView). That seems to be happening: CDC's count rose, the dairy outbreak is H5N1 clade 2.3.4.4b, and there is no 2025-vs-2026 date ambiguity. Backup path: additional contacts and workers at the two dairies, plus fall poultry outbreaks, produce more cases before Jan 8. BOTTOM LINE: A confirmed, dairy-exposed human avian influenza case in Yakima County was announced Oct 15, 2026, in an outbreak officially identified as H5N1. That makes YES very likely already satisfied, and the remaining risk is mainly resolution-source technicalities. NOT FOUND: An explicit statement from DOH or CDC confirming the human case's subtype as H5N1 (the release only says "avian influenza"). CDC's case table and FluView Week 40 entry for this case. CIDRAP's full article text (HTTP 403).

YES means: the total of human H5N1 cases reported in the US during 2026 is above 0 under the source-agency rules. The strongest NO case is thin. A Yakima County, Washington case was announced on Oct 15, 2026, so NO now needs a technicality to hold. - [2026-10-15] The Yakima Health District release, coordinated with Washington DOH, calls it a "confirmed case of avian influenza" in a resident exposed to infected dairy cattle. The release does not say "H5N1" for the patient, and it does not mention CDC confirmation. H5N1 appears only in its sentence about the herd detections. That is the best NO technicality: a subtype or CDC-confirmation gap. The H5N5 case in Nov 2025 also had an H5 label before sequencing said otherwise. https://afludiary.blogspot.com/ (reproduces the release) - [2026-10-16] The Hogvet51 veterinary blog says human H5N1 cases are normally confirmed by CDC in Atlanta, and that state and local officials usually defer to federal labs. It notes the 10/16 FluView had no mention of the Washington case and that CDC may not yet have run its assays. It calls the human isolate "likely" H5N1. This supports a NO argument that the case is still pending and unsequenced. https://hogvet51.substack.com/p/yakima-county-wa-health-district - [2026-10-16] Feedstrategy and CIDRAP both describe the case as H5N1 and tied to cattle. CIDRAP says the person is not seriously ill and is isolating at home. These do not independently confirm the human subtype, since they appear to rely on the same health-district release. They weaken the subtype-mismatch argument, though not to zero. https://www.cidrap.umn.edu/avian-influenza-bird-flu/quick-takes-us-human-avian-flu-case-dengue-florida-plague-madagascar-mers - [2026-10-16] Poultrymed says the infection was confirmed by the Yakima Health District and Washington DOH. This is still state-level confirmation, not CDC. It undercuts the NO argument that the case is only "probable". https://www.poultrymed.com/ID-Eng-Yak161026 - [2026-10-02] CDC's front page had the "no unusual flu activity including A(H5N1)" banner dated Oct 2. The 71→72 change on the situation page is the only CDC-side sign of a new case. I found no CDC press release, and no CDC case-table entry that I could read. https://www.cdc.gov/bird-flu/index.html - [2026-09-26] CDC monitoring says animal and linked human data update on the first Friday of each month. This supports a NO argument that CDC's official count could lag. It does not help much, because the rules count newly reported cases through Jan 8 if backdated to 2026. https://www.cdc.gov/bird-flu/h5-monitoring/index.html - [2026-08-20] The CRS table (data downloaded Aug 20) lists 71 cases and no 2026 case, and the AAO and Stony Brook pages say the same for May and early 2026. So from Jan to early Oct 2026 the status quo was zero. The Yakima case is the only candidate for a 2026 case. https://www.congress.gov/crs-product/R48580 - [2026-10-16] Hogvet51 says WA DOH's own human-case table "acknowledg[es] the likely case". This implies a likely/probable label at the state level, not a final confirmed one. The CRS report shows CDC keeps probable cases (7) separate from its 71 confirmed. If CDC logs this case as probable, the NO argument is that it is excluded. https://hogvet51.substack.com/p/yakima-county-wa-health-district - [2026-10-16] A third Washington herd was confirmed on Oct 15, per Hogvet51, so exposure is growing. That makes further cases more likely, and so it hurts the NO case. https://hogvet51.substack.com/p/yakima-county-wa-health-district BOTTOM LINE: A Washington H5N1-linked human case was publicly announced as confirmed on Oct 15, 2026, so NO now depends on that case being dropped, reclassified as non-H5N1 or probable only, or not counted by the resolving source. Status-quo inertia no longer supports NO. NOT FOUND: A CDC or Washington DOH statement giving the human case's subtype or CDC confirmation status. The CDC case table entry for the 72nd case. The Kalshi source-agency hierarchy. Any report of the case being retracted.