Rising Measles Cases Trigger Global Alarm
A sharp rise in measles cases worldwide is serving as an early warning that other vaccine-preventable diseases may be set to follow, the World Health Organization said Friday. Dr. Kate O’Brien, who leads the WHO’s Department of Immunization, Vaccines and Biologicals, described measles as the “fire alarm” of declining vaccination coverage because the virus spreads so easily.
“When we see measles cases, it signals that gaps are almost certainly likely for other vaccine-preventable diseases like diphtheria or whooping cough or polio, even though they may not be setting off the fire alarm just yet,” O’Brien said. The WHO’s Progress Toward Measles Elimination report, released Friday, shows a global surge in measles infections, including in countries that had previously eliminated the disease.
Global and U.S. Outbreaks Intensify
According to the new report, an estimated 11 million measles infections occurred worldwide in 2024, nearly 800,000 more than in 2019. Last year, 59 countries experienced large outbreaks, and in 2025, the United States joined that list.
Whooping cough cases are also climbing sharply in the U.S. The CDC reports more than 20,000 infections so far in 2025, on pace to reach the highest level in a decade. The simultaneous rise in two major illnesses underscores how even modest drops in immunization rates can weaken population protection.
Elimination Status Under Threat
Measles elimination — meaning the virus no longer spreads within a country — is at risk in several nations. Eighty-one countries had achieved elimination by 2024, including Canada in 1998 and the United States in 2000. But elimination status can be lost when the same strain of measles circulates continuously for a full year.
Canada crossed that threshold this month. The U.S. may follow if ongoing outbreaks are linked to a Texas cluster that began in January. Many early U.S. samples were identified as genotype D8, and that same variant has now been detected in outbreaks in South Carolina, Utah and Arizona.
South Carolina officials have reported 58 infections, mostly in Spartanburg County. Along the Arizona–Utah border, infections continue rising: Arizona has logged 153 cases, nearly all in Mohave County, while Utah has reported 102 cases. Additional clusters have emerged near Salt Lake City.
Vaccination Declines Fuel the Spread
New data shows that routine childhood vaccination rates in the U.S. have slipped significantly. According to an NBC News review, 77% of counties have seen declines in immunization coverage since 2019, reducing the community protection needed to stop outbreaks from spreading.
As of Wednesday, the Centers for Disease Control and Prevention had confirmed 1,798 measles cases across 42 states in 2025. Three deaths have been reported — an adult in New Mexico and two young girls in Texas.
Experts warn that unless vaccination rates recover, more illnesses could follow. Rising cases of whooping cough, along with ongoing measles outbreaks, indicate a growing vulnerability to diseases that had once been largely contained through routine childhood immunization.