International health authorities will evaluate measles transmission data from the US and Mexico amid thousands of cases reported nationwide.
RT’s Three Key Takeaways:
- Status Review: The Pan American Health Organization (PAHO) will convene a closed-door meeting to evaluate whether the US and Mexico have lost their measles elimination status following sustained outbreaks.
- Transmission Benchmarks: The US met a key criterion for losing elimination status in January 2026 by recording 12 consecutive months of uninterrupted disease transmission.
- Rising Caseloads: Federal health tracking confirms more than 5,000 measles cases in the US during 2026, bringing the total to nearly 7,500 cases since the beginning of 2025.
This week, the US and Mexico will meet with the Pan American Health Organization (PAHO) for a three-day closed-door meeting to evaluate their respective measles elimination statuses.
The formal evaluation will occur during the annual meeting of the Regional Verification Commission for the Elimination of Measles, Rubella, and Congenital Rubella Syndrome (RVC), an independent technical body that reports to the director of PAHO. The meeting was originally scheduled for April 2026 but was postponed to November 2026 to allow authorities to finish technical analyses.
According to PAHO, the RVC defines endemic transmission as the uninterrupted circulation of the same virus genotype and lineage for 12 months or longer within a specific geographic area. In January 2026, the US reached that threshold, marking one full year of sustained transmission following the start of reported outbreaks on Jan 20, 2025.
Surveillance and Caseload Data
According to CDC data, more than 5,000 measles cases have been documented in 2026 and nearly 7,500 cases since the beginning of 2025. The 2025 surge followed 2,255 confirmed infections that year, which was previously the highest annual total reported in the country since 1991.
In addition, eight measles-related deaths across three states have been reported in 2026, though the CDC officially recognizes four as of November 2026. The US originally declared measles eliminated in 2000, a benchmark defined by the CDC as the absence of endemic transmission for 12 months or longer under an effective healthcare and surveillance infrastructure.
To support outbreak control, US health authorities have conducted viral genome sequencing and constructed a bioinformatics platform for molecular data analysis, which the commission will evaluate during the November review.
Regulatory Discussions and Regional Precedents
Despite the duration of transmission, federal officials argued in January that 12 continuous months of cases should not automatically trigger the loss of elimination status without demonstrating an epidemic linkage through a common source between cases.
The upcoming review follows widespread shifts in regional elimination classifications. In November 2025, PAHO revoked Canada’s elimination status after that country confirmed 5,197 cases in 2025. Under regional guidelines, the re-establishment of endemic circulation in Canada caused the entire Americas region to lose its status as free of endemic measles. Furthermore, international health panels recently revoked the elimination status of six European and Central Asian nations, including the United Kingdom, Spain, Austria, Armenia, Azerbaijan, and Uzbekistan.
Following the upcoming technical sessions, the RVC will deliver its findings and formal recommendations to the director of PAHO, who will communicate the official status determinations directly to member governments. PAHO emphasized that maintaining high vaccination coverage, sustaining active surveillance, and implementing rapid outbreak responses remain vital to stopping transmission across healthcare systems.
