GENEVA, Switzerland (AFP) — Measles infections soared by a fifth last year to over 10 million cases globally, revealing alarming gaps in vaccine coverage, a study showed Thursday.

Worldwide, there were an estimated 10.3 million measles cases in 2023, according to a joint publication by the World Health Organization (WHO) and the United States’ Centers for Disease Control and Prevention.

That marked a 20 percent increase from 2022, the study showed, saying that “inadequate immunization coverage globally is driving the surge in cases.”

Measles is one of the world’s most infectious diseases. At least 95 percent coverage with two doses of the measles/rubella vaccine is needed to prevent outbreaks.

But in 2023, only 83 percent of children worldwide received their first dose of the measles vaccine through routine health services — the same level as in 2022 but down from 86 percent before the pandemic.

Only 74 percent received their second dose last year, the study showed.

As a result of global gaps in vaccination coverage, 57 countries experienced large and disruptive measles outbreaks in 2023, up from 36 countries a year earlier, the study showed.

All regions except the Americas were impacted, it said, with nearly half of all large and disruptive outbreaks occurring in the African region.

“Measles vaccine has saved more lives than any other vaccine in the past 50 years,” WHO chief Tedros Adhanom Ghebreyesus said in a joint statement.

“To save even more lives and stop this deadly virus from harming the most vulnerable, we must invest in immunisation for every person, no matter where they live.”