Measles outbreak in US surpasses 930 cases as infectious disease expert warns world may have lost herd immunity
The growing measles outbreak that’s taken over North America this year — including nearly 1,000 cases in the US alone — may be indicative of the loss of herd immunity, an infectious disease expert is warning.
Although the US eradicated measles in 2000 by achieving herd immunity through mass vaccination, Dr. Paul Offit, of the Vaccine Education Center at the Children’s Hospital of Philadelphia, said the world may have reverted back to a “post-herd immunity” world when that level of immunization didn’t yet exist.
“I think the measles outbreak proves that,” Offit told The Guardian.
“Measles – because it is the most contagious of the vaccine-preventable diseases, the most contagious human disease really – it is the first to come back,” he said.
The US has struggled to maintain the 95% measles vaccination rate needed for herd immunity with a growing anti-vax movement, as only an estimated 91% of Americans are vaccinated against the disease, according to the National Foundation for Infectious Diseases.
Offit worries the loss of herd immunity being seen with measles could eventually spread to other infectious diseases.
The Centers for Disease Control and Prevention reported US measles cases had climbed to 935 in its last update Friday — at least 2,500 known cases have been seen across the US, Canada and Mexico — with the spread showing no sign of slowing.
Texas continues to be the epicenter of the disease in the US, with 683 confirmed cases since late January — including 20 new infections in the last week.
There have been three confirmed deaths in the US so far, including two unvaccinated elementary school children in Texas with no known underlying conditions, and an unvaccinated adult in New Mexico.
Officials also say the genetic strains of measles spreading in Canada — where the outbreak is believed to have started in the fall — matches the other large outbreaks being seen in the US and Mexico.
Nearly all of the infected — 96% — have been unvaccinated, according to CDC data.
This year’s surge more than triples the total count reported in 2024, when the US recorded just 285 cases.
As many as 13% of those sick with measles have needed to be hospitalized — up from 11% a week ago.
Measles is one of the world’s most contagious diseases and can lead to dangerous complications such as pneumonia, blindness, brain swelling and death.
Before the measles vaccine was available, 400 to 500 people died of measles each year in the US, 48,000 were hospitalized and 1,000 suffered swelling of the brain, according to the CDC.
Meanwhile, Health and Human Services Secretary Robert F. Kennedy Jr. said this week the media should pay more attention to diabetes and autism — not measles — as an “existential threat” to the nation’s health.
