Waning vaccine coverage has fueled a 20% spike in measles cases worldwide, with 10.3 million people struck by the preventable illness in 2023, health officials reported Wednesday.
"Inadequate immunization coverage globally is driving the surge in cases," of what was once a common childhood disease, the World Health Organization and the U.S. Centers for Disease Control and Prevention said in a joint statement issued by both agencies.
"The number of measles infections are rising around the globe, endangering lives and health," CDC Director Dr. Mandy Cohen said in the statement. "The measles vaccine is our best protection against the virus, and we must continue to invest in efforts to increase access."
"Measles vaccine has saved more lives than any other vaccine in the past 50 years," WHO Director-General Dr. Tedros Adhanom Ghebreyesus said in the statement. "To save even more lives and stop this deadly virus from harming the most vulnerable, we must invest in immunization for every person, no matter where they live."
How dire is the situation?
More than 22 million children did not receive even a first dose of the two-dose measles vaccine in 2023, according to the WHO and CDC. Globally, roughly 83% of children received a first dose of the vaccine last year, while only 74% received a second dose.
Unfortunately, health officials recommend at least 95% vaccination coverage to prevent outbreaks. An infected person can spread the highly contagious disease to up to 90% of people close to them if they are not immune, according to the CDC.
Because of global gaps in vaccination coverage, 57 countries experienced measles outbreaks in 2023, the agencies noted, representing a nearly 60% increase from 36 countries in 2022. Nearly half of all outbreaks occurred in the African region, according to the WHO.
In the United States, measles vaccination rates among kindergartners have missed the federal target for four years in a row and fell to 92.7% coverage in 2023, according to CDC data.
The drop in vaccination coverage has had consequences: An estimated 107,500 people worldwide, mostly children under the age of 5, died from measles in 2023.
While that represents an 8% decrease from the year before, the agencies said the “slight reduction in deaths” was mainly because the biggest surges took place in regions of the world where children with the disease were less likely to die because they had access to health care.
In the United States, 277 measles cases were reported in 31 states and Washington, D.C., in 2024, with 16 outbreaks, according to the CDC. Last year, only four outbreaks were reported in the United States.
Measles symptoms tend to include a high fever, cough, conjunctivitis (pink eye), runny nose, white spots in the mouth and a rash that spreads from head to toe. Infants and young children are most at risk of serious complications from the disease that include pneumonia or swelling of the brain, the WHO says.
Vaccination coverage for measles fell globally during the pandemic, reaching the lowest levels seen since 2008.
The new data on measles was published Thursday in the CDC publication Morbidity and Mortality Weekly Report.