On Sept. 27, 2016, the Region of the Americas was the first in the world to have eliminated measles, a viral disease that can cause severe health problems, including pneumonia, brain swelling and even death. This achievement culminated a 22-year effort involving mass vaccination against measles, mumps and rubella throughout the Americas.

Measles was the fifth vaccine-preventable disease to be eliminated from the Americas, after the regional eradication of smallpox in 1971, poliomyelitis in 1994, and rubella and congenital rubella syndrome in 2015.

Before mass vaccination was initiated in 1980, measles caused nearly 2.6 million annual deaths worldwide. In the Americas, 101,800 deaths were attributable to measles between 1971 and 1979. A cost-effectiveness study on measles elimination in Latin America and the Caribbean has estimated that with vaccination, 3.2 million measles cases will have been prevented in the Region and 16,000 deaths between 2000 and 2020.

Measles transmission had been considered interrupted in the Region since 2002, when the last endemic case was reported in the Americas. However, as the disease had continued to circulate in other parts the world, some countries in the Americas experienced imported cases. The International Expert Committee reviewed evidence on measles elimination presented by all the countries of the Region between 2015 and August 2016 and decided that it met the established criteria for elimination. The process included six years of work with countries to document evidence of the elimination.

Measles is one of the most contagious diseases and affects primarily children. It is transmitted by airborne droplets or via direct contact with secretions from the nose, mouth, and throat of infected individuals. Symptoms include high fever, generalized rash all over the body, stuffy nose, and reddened eyes. It can cause serious complications including blindness, encephalitis, severe diarrhea, ear infections and pneumonia, particularly in children with nutritional problems and in immunocompromised patients.

As a result of global measles elimination efforts, only 244,704 measles cases were reported worldwide in 2015, representing a significant decline from earlier years. However, more than a half of these reported cases were notified in Africa and Asia.

To maintain measles elimination, PAHO/WHO and the International Expert Committee have recommended that all countries of the Americas strengthen active surveillance and maintain their populations’ immunity through vaccination.