WASHINGTON, United States (CMC) –  The Pan American Health Organization (PAHO) has called on countries, including those in the Caribbean, to strengthen surveillance, laboratory diagnosis, outbreak response, and vaccination campaigns amid concerns that the Region of the Americas has lost its verification as free from endemic measles transmission.

PAHO said that the decision follows the conclusion of the PAHO Measles, Rubella, and Congenital Rubella Syndrome Elimination Regional Monitoring and Re-Verification Commission, which met in Mexico City earlier this month to review the epidemiological situation across the region.

It said the Commission determined that endemic measles transmission has been reestablished in Canada, where the virus has circulated for at least 12 months.

As a result, the Americas, which was the first region in the world to eliminate measles twice, has now lost its measles-free status. All other countries continue to maintain their measles elimination status.

“This loss represents a setback, but it is also reversible,” said PAHO Director, Dr Jarbas Barbosa.

“Until measles is eliminated worldwide, our region will continue to face the risk of reintroduction and spread of the virus among unvaccinated or under-vaccinated populations. However, as we have demonstrated before, with political commitment, regional cooperation, and sustained vaccination, the region can once again interrupt transmission and reclaim this collective achievement,” he added.

PAHO said that as of November 7, this year, 12,596 confirmed measles cases have been reported across 10 countries, approximately 95 per cent of the region’s cases in Canada, Mexico and the United States, a 30-fold increase compared to 2024.

It said 28 deaths have been recorded, 23 in Mexico, three in the United States, and two in Canada.

PAHO said active outbreaks are ongoing in Canada, Mexico, the United States, Bolivia, Brazil, Paraguay, and Belize, mostly triggered by imported cases.

“Transmission has primarily affected under-vaccinated communities, with 89 per cent of cases occurring in unvaccinated individuals or those with unknown vaccination status. Children under one year of age are the most affected, followed by those aged one to four year,”  PAHO said.

It said Canada’s measles outbreak began in October 2024 in the province of New Brunswick and has since spread nationwide, with more than 5,000 confirmed cases reported nationwide. Although declining, transmission persists in Alberta, British Columbia, Manitoba, and Saskatchewan.

Measles is highly contagious. A single infected person can transmit it to up to 18 others. Severe complications can include pneumonia, encephalitis, blindness, and death. Outbreaks also disrupt daily life and place additional pressure on health systems.

PAHO said vaccination remains the most effective means of protection and that over the past 25 years, the measles vaccine has prevented more than six million deaths across the Americas, and an estimated 15 million deaths over the last 50 years.

It said nevertheless, in 2024, regional coverage for the second dose of the measles, mumps and rubella vaccine (MMR2) averaged 7 per cent, well below the 95 per cent needed to prevent outbreaks.

In addition, only 31 per cent of countries reached 95 per cent or more coverage for the first dose, and just 20 per cent achieved that level for the second dose.

PAHO said it is continuing to provide technical support to countries to strengthen surveillance, laboratory diagnosis, outbreak response, and vaccination campaigns. Experts have been deployed to several countries and the organisation is monitoring risks in Belize, Brazil and Paraguay.

“Every case we prevent, every outbreak we stop saves lives, protects families, and makes communities healthier,” said Barbosa.

“Today, rather than lamenting the loss of a regional status, we call on all countries to redouble their efforts to strengthen vaccination rates, surveillance, and timely response to suspected cases—reaching every corner of the Americas. As a region, we have eliminated measles twice. We can do it a third time,” he said.

PAHO said it is strongly encouraging countries to continue strengthening surveillance, immunisation and outbreak rapid response activities for every suspect case, expand and consolidate electronic immunisation registries across all countries, following PAHO’s established guidelines.

It is also urging countries to maintain sustainable laboratory surveillance by allocating sufficient financial and human resources, adding that for suspected cases with clinical and epidemiological risk factors and a negative measles IgM result, with specimens collected within 0–3 days after rash onset, perform PCR testing to confirm or rule out infection.

PAHO reiterated that the Americas have previously faced setbacks, including the temporary loss of measles elimination status in Venezuela (2018) and Brazil (2019).

“The region regained elimination status in 2024 through coordinated regional action. To regain measles elimination status, a country must demonstrate interruption of endemic transmission for at least 12 consecutive months, supported by comprehensive vaccination, surveillance, and outbreak-response data,” it said.

Barbosa said that cooperation, solidarity, and science are stronger than any virus “because when we work together, we protect the health and lives of all people in the Americas”.