Global measles cases rose 18% in 2022 amid low vaccination rates: Report

Global cases of measles increased by 18% from 2021 to 2022, following a drop in vaccinations over the past few years, according to a new report Thursday from the World Health Organization and Centers for Disease Control and Prevention.

Deaths due to measles have also increased globally by 43% from 2021 to 2022, the new data shows.

"The alarming increase in measles cases and deaths globally is a clear warning sign," said Dr. John Brownstein, an ABC News medical contributor and chief innovation officer at Boston Children's Hospital. "The drop in vaccination rates over recent years has set the stage for this resurgence, particularly impacting children who are most vulnerable."

So far this year in the United States, 41 measles cases have been reported by more than a dozen states. Domestic cases of measles surged in 2019, with an estimated 1,274 people sick in at least 31 states -- the greatest number of cases reported since 1992.

"The recent outbreaks of measles in the U.S. are a stark reminder of the consequences of vaccine hesitancy, emphasizing the need for robust public health campaigns to bolster confidence in and uptake of the MMR [measles, mumps and rubella] vaccine," Brownstein said.

Most of the cases were among young people who were not vaccinated, and most outbreaks occur in groups of people who are not up to date on their vaccines.

An estimated 92% of American adolescents aged 13-17 were vaccinated against measles in 2019, according to the CDC. The federal agency notes that a vaccination coverage rate of 95% with both doses is necessary to protect communities from outbreaks.

Childhood immunizations overall -- including the measles, diphtheria, tetanus and pertussis (DTaP), polio and chickenpox vaccines -- have dipped in recent years among kindergarteners, decreasing from 95% in 2019 to 94% in 2020, then to 93% in 2021, according to the CDC.

The MMR vaccine is about 93% effective against measles, increasing to 97% after the second dose, according to the CDC.

Children in the U.S. need two doses of the MMR vaccine for best protection. The first dose is given between 12-15 months of age followed by a second dose between 4 to 6 years of age.

According to the latest global report from health officials, a total of 37 countries experienced large outbreaks in 2022 compared to 22 countries in 2021.

The majority of the countries with outbreaks were located in Africa, as well as a handful in the Eastern Mediterranean region.

"The rise in measles [is] a reflection of a growing health crisis that disproportionately affects children, especially in low-income countries. It's crucial to close the immunization gap and guarantee every child access to essential vaccines," Brownstein said.

There were an estimated 9 million cases of measles and 136,000 deaths globally, mostly among children, according to the report.

There were 33 million children who missed a measles vaccine dose in 2022, including about 11 million getting their first shot but missing their second dose, the health agencies said.

Measles can cause serious health complications, especially in children younger than 5, according to the CDC. About one in five people in the U.S. who get measles will be hospitalized.