CDC: Surge in U.S. measles cases threatens elimination status

April 11 (UPI) -- More than 100 cases of measles were recorded in the United States since the beginning of 2024, and the rapid spread of the disease could threaten its elimination status, according to a report from the Centers for Disease Control and Prevention.

According to the CDC report issued Thursday, 338 confirmed measles cases occurred in the country since the beginning of 2020, 29% of which were recorded in 2024.

The median patient age was 3 years, and 91% of patients were unvaccinated or had unknown vaccination status, according to the CDC.

Measles was eliminated in the United States in 2000, meaning the disease is no longer constantly present, but occasional outbreaks do occur due to importations.

The United States nearly lost elimination status in 2019 due to prolonged outbreaks among under-vaccinated, close-knit populations in New York.

The high number of cases this year, 113 as of April 4, could put the country's elimination status at risk again, the report warned.

The largest outbreak in the United States this year began in a migrant shelter in Chicago. The city recorded 61 cases this year, with three this week.

The Chicago Department of Public Health since March has distributed more than 13,000 measles vaccines to contain the spread.

The CDC said, while the risk of widespread transmission still is low thanks to high population immunity, additional actions such as "encouraging vaccination before international travel and rapidly investigating suspected measles cases" are needed to change course.

The CDC recorded an average of five measles cases in the first quarter of each year from 2020-2023 due to low socialization from the COVID-19 pandemic.

"The rapid increase in the number of reported measles cases during the first quarter of 2024 represents a renewed threat to elimination," the report read.

Ninety-six percent of cases in the past four years were associated with importation from international travel, and 61% of those cases were among Americans who were unvaccinated or had an unknown vaccination status.

There have been no reported deaths from measles in the past four years, according to the CDC.

Measles is a highly contagious airborne illness that can cause severe health problems and even death. Young and unvaccinated children are especially vulnerable.

An infected person can spread the disease to up to 90% of people in close contact if none of those people is immune. Symptoms include fever, cough, runny nose, watery eyes and a rash of red spots.

The United States has set a target vaccination rate of 95%, but measles vaccination rates have dropped significantly below that in the past few years. Twelve states and Washington, D.C., had rates below 90% as of the 2022-2023 school year.

During that time, 93.1% of American kindergartners were fully vaccinated, down from 95% in in the 2019-20 school year.

Vaccination rates also declined worldwide, according to the CDC. Around 83% of people received one dose of the measles vaccine in 2022, down from 86% in 2019.