An electron micrograph of the measles virus. Credit: CDC/ Courtesy of Cynthia S. Goldsmith

Measles has been eradicated from the Americas after decades of vaccination efforts, the world's first region to rid itself of the highly contagious disease, global health authorities said Tuesday.

Measles remains a top killer of children worldwide, and took nearly 115,000 lives in 2014—or about 13 deaths every hour—according to the World Health Organization (WHO).

Before vaccination became widespread around the globe, measles killed about 2.6 million people per year.

"Endemic transmission of measles has been eliminated from the region," said WHO director Margaret Chan.

"The Americas region has shown that with strong national immunization programs... dedicated financing and strong political commitment and partner support, measles can be stopped," she added, describing it as "an outstanding achievement."

Measles is now the fifth vaccine-preventable disease to be eliminated in the Americas, after smallpox, polio, rubella and congenital rubella syndrome, according to the Pan American Health Organization (PAHO).

The end of endemic transmission means the virus is no longer commonly spread locally, although imported cases may still lead to isolated outbreaks.

The region of the Americas reported its last endemic case in 2002.

"However, since measles continues to circulate worldwide, some countries continued to report imported cases," PAHO said in a statement.

Over the past year, from August 2015 to August 2016, all countries in the Americas have showed documentation that endemic measles has been wiped out.

"This is a historic day for our region and indeed the world," said PAHO director Carissa Etienne.

"It is the result of a commitment made more than two decades ago, in 1994, when the countries of the Americas pledged to end measles circulation by the turn of the 21st century."

Highly contagious

Measles is a highly contagious virus that lives in the nose and throat of an infected person, and can linger in the air for hours, according to the US Centers for Disease Control and Prevention (CDC).

Symptoms include a reddish rash, white bumps inside the cheeks, fever, runny nose, and cough.

Severe complications can occur, leading to miscarriage in pregnant women as well as the risk of death by pneumonia or brain swelling.

A vaccine became widely available in 1963, but the virus has proven difficult to eradicate.

In recent years, measles outbreaks have risen in some parts of the United States and Europe where parents have refused to vaccinate their children.

When a person is infected outside the area and returns to an area with lower vaccination rates, more children are at risk of getting sick and spreading the disease.

"Sometimes people that are unvaccinated are in groups, so you can see a cluster of cases," said the CDC's Susan Reef, noting that just such an outbreak in California last year does not qualify as "endemic transmission."

Experts said the success of the Americas should not lead people to become complacent about vaccine efforts, which must be maintained at high levels to keep the virus at bay.

"It is my hope that other regions of the world are encouraged by the success of the Americas," said Chan.

"And that the lessons learned here serve them as they move forward toward their own elimination goals."

Measles: A grim reaper of children despite vaccine

Declared "eliminated" in the Americas on Tuesday, measles still kills tens of thousands of children in the world every year, despite the availability of safe, affordable and effective vaccines.

Things to know about measles:

WHAT IS IT?

Known for its characteristic reddish rash, measles is a highly contagious disease caused by a virus spread through physical contact or coughing and sneezing.

It can weaken the immune system and render children vulnerable to complications from diarrhoea, pneumonia and malnutrition. It can lead to blindness, deafness and brain damage.

In populations with high levels of malnutrition and poor healthcare, up to one in 10 measles cases results in death.

Being infected or innoculated confers protection against the virus for the rest of one's life.

There is no specific antiviral treatment, but symptoms can be alleviated through good nutrition and lots of fluids, and the treatment of associated eye and ear infections.

NUMBERS

About 115,000 people died of measles in 2014—an average of about 13 every hour. Most were children younger than five, a group among which measles remains a top killer.

In 1980, before widespread vaccination, measles claimed an estimated 2.6 million lives every year—dropping to 547,000 in 2000.

VACCINES

Measles vaccination caused fatalities from the disease to fall by nearly 80 percent between 2000 and 2014.

In 2014, about 85 percent of children received a single vaccination by their first birthday. Two doses are recommended to ensure immunity and prevent outbreaks.

Vaccination is estimated to have prevented more than 17 million deaths since 2000. Even so, millions of children go unvaccinated.

In poor countries, many people simply do not have access to the $1 vaccine (90 euro cents).

And in some rich nations, including the United States and in Europe, there is the constant risk of new outbreaks as some parents refuse let their children have the shot.

They cite fears that a triple vaccine for measles, mumps and rubella is responsible for causing autism—a theory traceable to a 1998 British study in The Lancet that has been debunked and officially retracted.

Last year, a measles outbreak began at a Disney theme park in California, sickening about 120 people, and the United States reported its first measles death in 123 years.

ERADICATED OR ELIMINATED?

Public health experts use different terms for describing the status of a disease that has been rolled back.

Elimination means stopping the disease from spreading in a given geographical area. The Americas is the world's first region to achieve this against measles.

Eradication means wiping out the disease permanently and globally. The only example of this in human history is smallpox, which was officially declared eradicated by the World Health Organization (WHO) in 1980 after a worldwide campaign of vaccination.