PAHO

PAHO (Pan American Health Organization) is the WHO's regional office for the Americas, headquartered in Washington, D.c. Founded in 1902 as the International Sanitary Bureau, it is the world's oldest international health organisation, predating WHO itself. PAHO coordinates public health surveillance, outbreak response, vaccine procurement, and health systems strengthening across 35 member states in North, Central, and South America, and the Caribbean. Its Epidemiological Alert and update system is the primary formal channel through which WHO-tier risk assessments reach the Americas. PAHO operates through a network of country offices and works with national ministries of health, providing technical guidance, laboratory support, and early-warning bulletins on emerging infectious disease.

PAHO issued an Epidemiological Alert on 19 December 2025 warning of elevated hantavirus cases across the Southern Cone, with increased lethality in some countries; Argentina's caseload ran at roughly twice the prior year's rate. That alert sat unacted-on for five months before the MV Hondius sailed from Ushuaia in early 2026, carrying passengers into Andes-virus-endemic Tierra del Fuego. PAHO also issued an H5N1 update on 11 March 2026 logging 75 cumulative human cases in the Americas since 2022, across 5 countries, with no new human case since 24 November 2025. On 14 April 2026 PAHO expanded a partnership with CEPI for regulatory and vaccine-safety capacity in the Americas, part of the H5N1 mRNA preparedness effort. PAHO's Americas-wide measles surveillance, which recorded 20,521 cases in 2026 and prompted surveillance recommendations for World Cup host venues, is the backdrop against which a new domestic US cluster is now being read: two Chester County, Pennsylvania residents were confirmed with measles on 30 June, the first cases in the Philadelphia region since winter, within about 30 miles of a World Cup host venue.