The Americas Just Eliminated Measles, But Vaccination Will Help It Stay Gone

A milestone in disease control

Earlier this week, the Pan American Health Organization/World Health Organization (PAHO/WHO) announced that after a 22 year eradication effort, measles had been eliminated in the Americas.

The victory was declared after a long campaign to vaccinate children against the highly contagious disease most often associated with a high fever and a rash. It can also cause brain swelling and death in severe cases; before a vaccine was developed, the measles killed millions of children worldwide.

But eliminating measles in the Americas isn’t the same as eradicating the disease. For a disease to be eradicated, it has to be absent in all parts of the world, like smallpox was in 1977, when the last naturally occuring case was contracted in Somalia. This news means that there are no longer any known cases caused by strains of the measles virus that are endemic, or native to the region.

In 2016, there have already been 54 cases of measles in the United States. In these instances, the individuals either contracted the disease while traveling outside of the Americas, or they acquired it from another person who had traveled outside and spread it around once they returned. As people go trotting around the globe, it’s not that uncommon for diseases like measles to travel with us.

Thanks to travel, diseases can rebound into a population quickly, even when the disease vector isn’t highly contagious to humans, and even if the distance travelled isn’t very far. Venezuela was the first country in the world to eliminate malaria in the 1960’s, but a recent economic downturn sent people in search of work out of cities and into rural areas where pockets of the disease had survived. There, in the swampy mosquito heaven that is illegal gold mines, the workers contracted the disease, and returned to the cities where it continued to spread through mosquito bites. Without sufficient medical supplies and treatments available the disease has made a horrifying comeback, with hundreds of thousands infected in recent years.

Unlike malaria, which has no commercially available vaccine, measles outbreaks are easily preventable. The measles mumps and rubella (MMR) vaccine is widely available, and can reduce the incidence of death by other infectious diseases.

But vaccinations only work if people get vaccinated. Measles outbreaks in 2014 and 2015 infected hundreds of people in the United States, and were traced back to a measles outbreak in the Philippines. The majority of people who contracted the disease in the United States during the 2015 and 2014 outbreaks were unvaccinated.

In order to prevent measles from spreading in a population 93 percent of people need to be vaccinated. According to the CDC’s latest National Immunization Survey, 23 states and Puerto Rico had MMR vaccination rates in children that were above that 93 percent threshold and 18 states had vaccination rates in children above 90 percent. But that still leaves a long way to go to minimize the risk of measles to communities across the United States.

Eliminating measles in the America’s is a great start, but until measles is permanently eradicated, like smallpox was in 1977, keep getting vaccinated.