The Pan American Health Organization (PAHO) is urging countries to strengthen vaccination and outbreak preparedness ahead of religious mass gatherings, warning that increased travel could accelerate measles transmission across the Americas.
In a regional risk assessment released Friday, PAHO said the risk of spread remains very high amid continuing outbreaks, vaccination gaps and cases appearing in new geographic areas.
The agency reported 55,792 confirmed cases and 77 deaths across 17 countries and territories between January 4 and October 3, 2026 – 4.8 times the number of cases recorded during the corresponding period last year.
Guatemala recorded the most cases, followed by Mexico, the United States, Peru and Canada. Together, the five countries accounted for 99.5 per cent of confirmed infections.
Cases were also reported in Argentina, Belize, Bolivia, Bonaire, Brazil, Chile, Colombia, Costa Rica, El Salvador, Honduras, Panama and Uruguay.
‘Measles is highly contagious, and we are seeing the consequences of gaps in vaccination coverage across the Americas,’ PAHO Director Dr Jarbas Barbosa said.
He urged parents to protect their children with the measles, mumps and rubella (MMR) vaccine and called on governments to close immunity gaps, strengthen surveillance and respond rapidly to infections.
PAHO said rising global cases increase the likelihood of infected travellers introducing the virus into communities with low immunity. People can transmit measles before its characteristic rash appears, potentially exposing others unknowingly.
Large gatherings and travel between countries and communities can further facilitate transmission, the agency warned.
‘Anyone planning to attend a large gathering should check that they are protected against measles,’ said Dr Daniel Salas, PAHO’s executive manager of Comprehensive Immunization.
He said domestic travellers could also face exposure when people from different regions gather. People aged six months and older without evidence of vaccination should receive a measles-rubella vaccine dose before travelling or attending a gathering, preferably at least two weeks beforehand, he added.
Regional vaccination coverage in 2025 reached 88 per cent for the first MMR dose and 85 per cent for the second, below the 95 per cent level PAHO said is needed to prevent outbreaks.
An estimated 1.6 million children in the Americas received no measles vaccine dose last year.
PAHO attributed the gaps to setbacks accumulated during the COVID-19 pandemic, vaccine hesitancy, difficulties delivering immunisation services and barriers to healthcare access, particularly among Indigenous peoples, migrants and displaced populations.
The agency said it is helping countries strengthen vaccination, laboratory surveillance, genomic monitoring, contact tracing and outbreak response.
With outbreaks continuing and major gatherings approaching, PAHO urged governments to expand access to vaccination while maintaining the capacity to detect and respond rapidly to cases.