Measles Cases Climb Across the Globe

The virus sickened an estimated nine million people worldwide in 2022, most of them children.

Measles cases worldwide rose 18 percent and deaths increased by more than 40 percent from 2021 to 2022 as countries struggled to get routine vaccinations back on track after the pandemic, according to a new report from the World Health Organization and the Centers for Disease Control and Prevention.

The report captures the continued burden of measles, one of the world’s most contagious diseases. In 2022, there were an estimated nine million measles cases and 136,000 deaths, according to the report.

The disease spreads when infected people cough or sneeze — someone can get infected by breathing in the virus, which can linger in the air for hours, or by touching a contaminated surface and then rubbing the eyes, nose or mouth. Vaccination is highly effective at stopping the spread of measles, and preventing people from getting sick if exposed to the virus. The measles vaccine, which experts say is ideally delivered in childhood, also includes protection against two other infectious diseases, mumps and rubella.

The report found that slightly more people were vaccinated against measles in 2022 than the year prior, but that nearly 33 million children still missed a dose of the vaccine. Worldwide, 74 percent of people were fully vaccinated, meaning they had received two doses. Low-income countries had the lowest vaccination rates, with only 66 percent of children receiving their first dose, and the highest risk of death from measles. Countries in Africa and Southeast Asia had particularly low coverage, said Cynthia Hatcher, a public health scientist at the C.D.C. who works on measles elimination in Africa.

Many areas are struggling to recover their public health systems in the wake of the Covid-19 pandemic, she said.

“Measles is really difficult — it will find even the smallest gaps in your protection,” she said. Public health officials estimate that 95 percent of people in a community must be fully vaccinated in order to prevent outbreaks, a concept known as “herd immunity.”

Most of the cases and deaths in 2022 occurred in children, who are at risk for severe complications from the disease, including pneumonia and brain swelling. More commonly, measles leads to fevers, rashes and coughs.

Large or disruptive outbreaks of the disease also became more widespread in 2022. Thirty-seven countries experienced such outbreaks that year, compared to 22 countries in 2021.

The rise in cases is likely a legacy of the pandemic, said Dr. Amesh Adalja, an infectious disease physician and senior scholar at the Johns Hopkins Center for Health Security. Vaccinations against many diseases, including measles, were “pushed off to the wayside” as people focused on Covid, he said. “There was just major disruption in getting children back on schedule — it’s harder than it appears to be,” he said. And many people avoided going to the doctor during the worst of the pandemic, delaying routine vaccinations and potentially leaving people susceptible, said Dr. Walter Orenstein, associate director of the Emory Vaccine Center.

While the burden of measles is largely concentrated abroad, the United States has faced its own challenges controlling the disease. In 2019, there were several large outbreaks across more than 25 states. So far this year, the C.D.C. has reported 41 measles cases nationwide.

But experts are eyeing the United States with concern: The pandemic, and misinformation about the safety and efficacy of Covid vaccines, has fueled vaccine hesitancy across the country, Dr. Adalja said. A C.D.C. report released this month showed that the number of vaccine exemptions increased slightly among U.S. kindergarten students between the 2021-22 and 2022-23 school years.

“What people need to understand, and where we have not done a good job in public health, is explaining to people that all vaccines are not created equal,” said Dr. Camille Sabella, a pediatric infectious disease specialist at the Cleveland Clinic. The C.D.C. estimates that two doses of the vaccine are 97 percent effective against measles. And it’s never too late for someone to get vaccinated.

“The way out of this is to increase vaccination rates and make sure all children have received their age-appropriate measles vaccination,” he said. “That’s really the only way out of this.”