As measles cases mount in the US, what's the situation worldwide?

Experts point to declining measles vaccination rates worldwide since the COVID-19 pandemic. In the United States, most states now are below the 95% vaccination threshold for kindergartners — the level needed to protect communities against measles outbreaks.

Britain reported 2,911 confirmed measles cases in 2024, the highest number of cases recorded annually, since 2012.

Measles cases in the United States last year were nearly double the total for all of 2023, raising concerns about the preventable, once-common childhood virus. Health officials confirmed measles cases in at least 18 states in 2024, including in New York City, Philadelphia and Chicago.

"Measles anywhere is a threat everywhere," the U.S. Centers for Disease Control say on their website.

Are measles outbreaks common outside the U.S?

According to the World Health Organization, an estimated 10.3 million people were infected with measles in 2023 and 107,500 died. Most were unvaccinated people or children younger than five. Cases were most common in parts of Africa, the Middle East and Asia where incomes are low and health services insufficient.

In places where measles have largely been eradicated, cases have been spread by travelers from other countries.

While measles-related deaths declined slightly in 2023, the number of outbreaks increased. Major outbreaks took place in 57 countries in 2023, including India and Indonesia, Russia, Yemen and Iraq. The largest number of cases in 2023 was 311,500 in the Democratic Republic of the Congo.

What is the impact of vaccinations?

The worldwide rate of childhood vaccinations has fallen in recent years, to 83% in 2023 from 86% in 2019, partly due to disruptions in immunization and health care due to the pandemic.

The WHO estimates that vaccination helped to prevent more than 60 million deaths worldwide between 2000 and 2023, as efforts to get the shots to more people ramped up. In 2000, 800,062 people are estimated to have died of measles. Before the vaccine was introduced in 1963, major epidemics caused about 2.6 million deaths a year.

Measles is so highly infectious that 95% immunity is required to prevent epidemics, the WHO says. Put another way, it infects about 9 of 10 people exposed if they lack immunity.

What international efforts are underway to prevent epidemics?

The WHO and others are backing an effort called "Immunization Agenda 2021-2030," to push for elimination of measles.

Independent experts declared the Americas free of endemic measles in 2016 but that status was lost in 2018 due to measles outbreaks in Brazil and Venezuela. Reduced vaccination rates are undermining efforts to fully eradicate the disease, experts say.

Global health organizations and other groups have increased their efforts to speed up immunization programs and close the gaps in prevention.