A significant increase in measles cases in early 2024 is threatening the United States’ status of measles elimination, a situation last encountered in 2019 when long-lasting outbreaks posed a similar threat, according to the Centers for Disease Control and Prevention (CDC).
CDC scientists highlighted this concern in the Morbidity and Mortality Weekly Report (MMWR). Their analysis, covering January 1, 2020, to March 28, 2024, revealed that measles cases in the first quarter of 2024 have surged 17 times compared to the average for the same period from 2020 to 2023.
As of March 28, 97 cases had been reported to the CDC.
By April 4, this number had increased to 113 cases across 18 jurisdictions. Of the 20 outbreaks involving three or more cases reported since 2020, seven occurred in 2024.
Maintaining the measles elimination status, which is crucial for reducing cases, deaths, and costs, requires that no outbreak lasts for 12 months or more in areas with effective surveillance systems.
The last significant threat to the U.S. elimination status occurred in 2019, due to prolonged outbreaks in under-vaccinated communities in New York City and New York state.
Given the rapid increase in cases in 2024, the CDC stressed the need for intensified efforts to boost measles, mumps, and rubella (MMR) vaccine coverage, particularly in closely-knit and under-vaccinated communities. Additional measures include promoting vaccination before international travel and quickly investigating suspected measles cases.
Most of the current cases are considered imported, with 61% occurring in U.S. residents who were eligible for vaccination but were either unvaccinated or had unknown vaccination status.
The CDC also noted a shift in the regions where people were exposed to the virus abroad.
Previously common regions like the Eastern Mediterranean and Africa were joined by Europe and Southeast Asia, with a 50% increase in cases from these areas in 2024.
Globally, a decline in measles vaccination rates is also contributing to the rise in cases. Estimates show that first-dose coverage dropped from 86% in 2019 to 83% in 2022, leaving nearly 22 million children under one year old vulnerable to the virus.
In related news, the Detroit Health Department reported a fifth measles case in Michigan involving a 4-year-old child.
Meanwhile, the Chicago Department of Public Health reported three additional cases, bringing the city’s total to 61, most linked to an ongoing outbreak at a migrant shelter.
