Why the US, Mexico and Guatemala may lose their measles-free status

Detailed summary

An independent commission is reviewing whether countries in the Americas still meet measles elimination criteria.

International health experts are meeting in Washington, DC, this week to determine which countries in the Americas have endemic measles transmission.

The outcome could decide whether the United States, Mexico and Guatemala retain their “measles elimination status”: a designation that the virus has not spread uncontrolled domestically for at least 12 months.

The Pan American Health Organization’s (PAHO) Regional Monitoring and Re-Verification Commission (RVC) began its annual conference on Tuesday to assess the countries’ status. The conference will adjourn on Friday.

The review comes as a sharp resurgence of the virus has spread across the Americas, with the US experiencing its largest and deadliest measles outbreak in nearly 30 years. The US has held its elimination status since 2000, but it risks losing it this year.

The commission will review reports submitted by all 35 PAHO member states, with particular attention to countries experiencing prolonged outbreaks.

How does the process work? Al Jazeera breaks down what happens in this explainer.

The RVC is an independent panel of international experts in epidemiology, public health and virology. The group advises PAHO, which is part of the World Health Organization, on which countries have maintained the elimination of measles and rubella.

The Americas became the first region in the world to eliminate endemic measles transmission in 2016, following decades of vaccination campaigns. For this year’s review, the commission is examining epidemiological data from 2025 and the first half of 2026.

The US, Mexico, Guatemala, Peru and Bolivia are at risk. Canada lost its status last November.

Opening of the article, excerpted from Al Jazeera. To read the rest, open the article on the publisher's site.