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New estimates put the number of measles deaths in 2018 at 142,300, a nearly 15% increase over the previous year, according to a new report by the World Health Organization and the US Centers for Disease Control and Prevention. The vast majority of deaths occurred in children less than five years of age, with the worst impacts felt in sub-Saharan Africa due to a lack of adequate immunization.

Measles is an infectious disease caused by a small spheroid-shaped virus. It's highly contagious, spreading from human to human via contact with droplets usually secreted from the respiratory tract via coughing and sneezing. Complications include fever, pneumonia and swelling in the brain, which can result in death -- particularly in young and malnourished children. However, a safe and effective measles vaccine has existed for over 50 years.

"The fact that any child dies from a vaccine-preventable disease like measles is frankly an outrage and a collective failure to protect the world's most vulnerable children," said Dr Tedros Adhanom Ghebreysus, the WHO's director-general.

Since 2000, the WHO estimates vaccination has prevented over 21 million deaths. However, the disease has been making a comeback in recent times. In January, the WHO declared the anti-vax movement and vaccine hesitancy as one of the top 10 health threats in 2019. Misinformation spread through social media and has seen a rise in the reluctance or refusal to vaccinate which, the WHO warned, could "reverse progress made in tackling vaccine-preventable diseases."

In 2018, the highest rate of measles incidence occurred in the Democratic Republic of the Congo, and so far the country has recorded 5,000 deaths in 2019. Armed conflicts in some of the provinces, in addition to violence directed at health works, make it difficult to access regions and provide vaccines to vulnerable populations.

A similar outbreak is occurring on the Pacific island nation of Samoa, after vaccination rates plummeted in 2018. The Samoan Prime Minister has enforced a two-day shutdown as an epidemic, that has so far killed 62 people, sweeps across the country.