Timeline

1. 10 Jun 2026
   WHO and IAATO inspection team en route to Rotterdam ahead of June 12 final biosafety check for MV Hondius. ECDC marks day 22 without a new case — no classification change before inspection outcome. WHO-IMO Antarctic code enters final editorial stage, June 20 release on track. Argentina holds at 121/38, third straight day of zero new cases. CDC upgrades Coconino County (AZ) and San Juan County (UT) to elevated risk as the US passes the statistical peak-window midpoint at 24 cases.
2. 9 Jun 2026
   WHO and IAATO begin pre-inspection logistics for the June 12 MV Hondius Rotterdam visit — documentation and travel arrangements confirmed. ECDC marks day 21 without a new Hondius-linked case; residual cohort follow-up now routine. Argentina holds at 121/38 for a fourth straight week of declining incidence. CDC issues a pre-peak Southwest advisory as the US deepens into the June-July window at 24 cases. WHO-IMO legal review of the expedition biosafety code is complete; June 20 draft confirmed on schedule.
3. 8 Jun 2026
   WHO and IAATO say MV Hondius refit is about 90% complete ahead of a June 12 final inspection in Rotterdam. ECDC keeps the cluster in LOW-risk review after 20 days without a new case. The US season holds at 24 entering the June-July exposure window, while Argentina remains at 121/38 in sustained decline.
4. 7 Jun 2026
   WHO says only a final small Hondius contact cohort remains under active 60-day follow-up. The expedition biosafety code consultation closes with broad support for onboard PCR and isolation minimums. Argentina remains at 121/38 in a low-transmission phase.
5. 6 Jun 2026
   ECDC downgrades the Hondius cluster from MODERATE to LOW after Dutch and French cohorts clear follow-up. MV Hondius crew biosafety certification is completed in Rotterdam. Chile formally closes its 2026 season at 14 cases and 3 deaths.
6. 5 Jun 2026
   CDC issues a June cleanup reminder after the US total reaches 24 cases. WHO-IMO moves the expedition biosafety code into legal review after 60+ submissions. Argentina holds at 121/38 as the national curve flattens further.
7. 4 Jun 2026
   WHO and IAATO schedule a June 9 joint inspection for MV Hondius in Rotterdam. Montana confirms a new Sin Nombre HPS case, raising the US total to 24. France closes tertiary Hondius tracing with zero onward transmission.
8. 3 Jun 2026
   ECDC says the first Hondius 60-day cohorts exit monitoring without positives and opens review for LOW-risk status. WHO-IMO publishes diagnostics and isolation chapters of the expedition code for comment. Argentina remains at 121/38 in a third week of decline.
9. 2 Jun 2026
   MV Hondius isolation cabin construction is completed in Rotterdam. Chile says its 2026 season is operationally closed at 14/3. The Netherlands clears its earliest monitoring cohorts with no secondary transmission.
10. 1 Jun 2026
    IAATO interim biosafety rules enter force for Antarctic operators. Argentina ticks to 121/38 after an isolated Rio Negro detection, but the broader decline holds. ECDC reports no new Hondius-linked positives through day 13 after the MODERATE downgrade.
11. 31 May 2026
    WHO and IMO open targeted consultation with operators and flag states on the new expedition biosafety code. CDC says the Colorado HPS patient remains stable with no secondary exposures identified. ECDC reaches day 12 without a new Hondius-linked positive.
12. 30 May 2026
    WHO publishes the Rotterdam refit timeline for MV Hondius. Argentina remains at 120/38 as the post-peak decline continues. CDC expands deer mouse surveillance in New Mexico and Arizona as the summer exposure window opens.
13. 29 May 2026
    ECDC weekly bulletin confirms Hondius cluster at MODERATE risk — no new cases in 10 days, 95%+ of contacts past 30-day midpoint symptom-free. CDC issues 2026 summer hantavirus advisory for Southwest with peak window June–July. WHO-IMO code 40% finalised, on track for June 20 draft.
14. 28 May 2026
    ECDC formally downgrades Hondius cluster risk from HIGH to MODERATE — 10 days without new cases, no tertiary transmission confirmed. MV Hondius Rotterdam refit: PCR laboratory installation completed, isolation cabin work begins. Argentina 120/38 unchanged — Neuquén reports zero new weekly cases.
15. 27 May 2026
    ECDC: 93% of Hondius contacts past 30-day midpoint with no symptoms — formal risk downgrade review initiated. WHO-IMO second taskforce session confirms June 20 code deadline achievable. Chile season at 14 cases with no new cases in 10 days — approaching seasonal close.
16. 26 May 2026
    MV Hondius arrives Rotterdam shipyard — PCR lab and isolation cabin refit begins. US 2026 season reaches 23 cases after new Colorado HPS case (Sin Nombre, rural Montrose County, stable). Argentina enters second consecutive week of declining incidence — 120/38.
17. 25 May 2026
    All 17 MV Hondius cases fully discharged or in community recovery — outbreak status moves to monitoring-only. WHO-IMO taskforce releases first working draft of Antarctic expedition vessel biosafety code. Argentina 119/38 with seasonal peak confirmed passed — week-over-week rate declining for first time.
18. 24 May 2026
    MV Hondius departs Tenerife for Rotterdam biosafety refit. US Southwest season holds at 22 for five consecutive days — possible plateau signal. Chile Aysén reservoir density declining with autumn season shift.
19. 23 May 2026
    WHO formally grants conditional return-to-service approval for MV Hondius — PCR lab and isolation cabin upgrades required before resuming operations. ECDC contact monitoring: majority of Hondius contacts past 30-day midpoint with no new positives. Argentina late-May peak transition signalled.
20. 22 May 2026
    WHO approves Hondius biosafety compliance package — conditional sign-off issued, firm departure date expected within 48 hours. WHO-IMO taskforce sets June 20 deadline for first draft expedition biosafety code. Argentina edges to 118/38.
21. 21 May 2026
    ECDC publishes updated rapid risk assessment formalizing 14-day pre-symptomatic contact tracing window and maintaining HIGH risk classification. Hondius operator submits return-to-service compliance package to WHO — decision expected within 5 days. Argentina season edges to 117/38 as late-May peak extends. All 17 Hondius cases remain stable. No new cases confirmed.
22. 20 May 2026
    WHO and IMO hold first taskforce meeting to codify Antarctic expedition biosafety standards. CDC updates HPS clinical workflow for ED and ICU teams. ECDC broadens contact tracing after pre-symptomatic Andes RNA finding. France third-generation contacts remain asymptomatic. Italy and Netherlands remain stable. Argentina remains at 116/38.
23. 19 May 2026
    Netherlands confirms 17th global Hondius case (third Dutch passenger). WHO and IMO launch joint biosafety taskforce for Antarctic expedition vessels. CDC reports one new US domestic HPS case (US total 22). Argentina rises to 116/38. Chile confirms 14th case. France reports no new tertiary positives.
24. 18 May 2026
    MV Hondius decontamination clearance certificate officially signed. WHO full interim biosafety rules published (28 pp). ECDC: Andes virus RNA detected in nasal secretions 48–72 h pre-symptom — confirms pre-symptomatic infectious window. France both P2P cases improving, moved to ward. Germany all 21-day contacts cleared. Italy 15th case improving. Netherlands 16th case contacts asymptomatic. CDC updates HPS guidance to 60-day monitoring. Chile Aysén rodent density above outbreak threshold. Argentina 115/38 at seasonal peak.
25. 17 May 2026
    France confirms second P2P Hondius event — genomic sequencing conclusive (France now 2 P2P events). Netherlands adds 16th case. WHO expert panel concludes: onboard PCR and isolation cabin mandatory for all Antarctic cruises. USA 2026 season reaches 21 cases. Argentina reaches 115 cases / 38 deaths.
26. 16 May 2026
    Italy confirms 15th case (Spallanzani, stable) — 10th country affected. WHO expert panel opens in Geneva. France second household contact symptomatic (under investigation). IAATO biosafety framework updated — mandatory from June 1. UK clears all Hondius contacts. Argentina 114 / 38. Chile 13 cases.
27. 15 May 2026
    Germany confirms 14th case — last remaining Hondius contact tests positive (Munich, stable). WHO extends household contact monitoring to 60 days. ECDC HIGH risk maintained; updated rapid risk assessment published. Nature Medicine: Andes R₀ ≈ 0.5 below epidemic threshold. Switzerland patient upgraded to stable. Spain surface sampling negative — MV Hondius clearance on track for May 18. Argentina reaches 112 cases / 37 deaths.
28. 14 May 2026
    CONFIRMED: France reports first proven P2P Andes virus transmission — Lyon couple, genomic analysis conclusive. ECDC upgrades EU/EEA risk to HIGH. Belgium confirms 12th case (UZ Leuven, stable). Switzerland confirms 13th case (Zurich, serious). CDC revises Andes P2P guidance. Argentina reaches 110 cases / 36 deaths. IAATO formally adopts WHO biosafety requirements.
29. 13 May 2026
    Germany confirms 11th case (Munich, stable) — one of 3 contacts under observation. Spain investigation report: rodent excreta (O. longicaudatus) found in 3 below-deck areas. WHO issues interim expedition vessel biosafety guidance. Argentina season reaches 108 cases / 35 deaths. NEJM rapid case series published. Australia clears all 6 monitored contacts.
30. 12 May 2026
    New Zealand confirms 10th case (Auckland ICU) — NZ first-ever hantavirus case. Netherlands and France each confirm 2nd Hondius case. WHO full genome sequencing: no definitive P2P evidence. CDC extends US monitoring to 45 days. Argentina season reaches 106 cases.
31. 11 May 2026
    Canada confirms 8th case (passenger, British Columbia). WHO releases preliminary P2P findings: ‘limited but not conclusive’ evidence of person-to-person transmission. ECDC upgrades EU risk to moderate. Spain drafts mandatory biosafety protocol for Antarctic-route vessels.
32. 10 May 2026
    All passengers disembarked. Vessel enters decontamination. WHO convenes emergency expert meeting on Andes P2P transmission. 7th case confirmed (crew member, Argentina).
33. 9 May 2026
    MV Hondius arrives Tenerife. Disembarkation begins under public health supervision. US CDC charters flight for American passengers.
34. 8 May 2026
    WHO confirms 6 cases. Ireland, Belgium, Australia, New Zealand begin contact tracing. 16+ countries now involved.
35. 7 May 2026
    CDC issues Level 3 Travel Health Notice (Avoid Nonessential Travel). UK UKHSA activates national response.
36. 6 May 2026
    Andes strain genetically confirmed. Spain authorises Canary Islands (Tenerife) docking.
37. 5 May 2026
    Cape Verde refuses docking on public health grounds. Hondius anchors off Praia.
38. 4 May 2026
    WHO publishes Disease Outbreak News DON-599. Three deaths confirmed.
39. 2 May 2026
    WHO formally notified. RT-PCR confirms hantavirus in multiple samples.
40. 26 Apr 2026
    Second death after emergency disembarkation in Buenos Aires.
41. ~15 Apr 2026
    First passenger develops symptoms; evacuated to hospital.
42. 20 Mar 2026
    MV Hondius departs Ushuaia, Argentina. ~200 passengers, 13 nationalities.