Surge in Measles Cases Calls for Boost in Vaccination Efforts

Measles vaccination.

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April 10, 2024, DETROIT – A 4-year-old child in Detroit has contracted measles, marking the state’s fifth case this year, according to health officials. The child, who was not vaccinated, is currently following isolation protocols to prevent the spread of the virus. Authorities emphasized that the child had not attended school or daycare, which could help limit the outbreak.

The Detroit Health Department highlighted the risk posed by measles, noting that the virus can linger in the air for up to two hours. As measles is highly contagious, officials warn that 90% of unvaccinated individuals exposed to the virus will likely contract it. The public is advised to monitor for symptoms for 21 days if they believe they have been exposed.

Health officials also want to reassure the public that financial constraints or lack of insurance should not deter individuals from getting vaccinated, stressing that measures are in place to provide access to vaccinations for everyone.

In a recent report by the CDC, at the end of 2023, US measles elimination status was maintained due to the absence of sustained measles virus transmission for 12 consecutive months and the presence of a well-performing surveillance system. Despite this, the risk for widespread US measles transmission remains low due to high population immunity. The increase in cases during the first quarter of 2024 indicates that additional activities are needed to enhance routine measles, mumps, and rubella vaccination coverage, particularly among close-knit and under-vaccinated communities. These activities should include promoting vaccination before international travel and rapidly investigating suspected measles cases.

3 Key Takeaways

There has been a notable rise in measles cases in the US early in 2024, with 97 new cases in the first quarter, which is much higher compared to previous years.
The US measles surveillance system, rapid case detection, and comprehensive case investigation is key to controlling outbreaks and ensuring sustained elimination of measles within the country.
Maintaining high vaccination coverage is essential to prevent the spread of measles and sustain its elimination status in the US.

During the specified period, the CDC was notified of 338 confirmed measles cases. Notably, 97 (29%) of these cases occurred during the first quarter of 2024, representing a more than seventeenfold increase over the mean number of cases reported during the first quarters of 2020–2023. Among the reported cases, the median patient age was 3 years, with ages ranging from 0 to 64 years. Most patients, 309 (91%), were unvaccinated or had unknown vaccination status. Additionally, 336 case investigations included information on ≥80% of critical surveillance indicators. From 2020–2023, the longest transmission chain lasted 63 days.

“Investigation of almost all U.S. measles cases reported since January 2020 were import-associated, included complete information on critical surveillance variables, were laboratory-confirmed by rRT-PCR, and underwent genotyping; these findings indicate that the U.S. measles surveillance system is performing well,” according to the CDC. “A variety of transmission chain sizes were detected, including isolated cases, suggesting that sustained measles transmission would be rapidly detected.”

To assess the status and context of measles elimination, the CDC analyzed epidemiologic and laboratory surveillance data along with the performance of the US measles surveillance system after the 2019 outbreaks. This analysis covers the period from January 1, 2020, to March 28, 2024.

“Rapid detection of cases, prompt implementation of control measures, and maintenance of high national measles vaccination coverage, including improving coverage in under-vaccinated populations, is essential to preventing measles and its complications and to maintaining US elimination status,” stated the CDC.

Limitations from this study include, underreporting of importations as 4% of cases during the study period had no identified source, and the investigations that exclude a measles diagnosis are not nationally reportable. Surveillance is sensitive to identify isolated cases and outbreaks. Lastly, the date of the first case report was missing for 35% of the investigations.

The 4-year-old child in Detroit contracted measles, marking the fifth case in the state this year. The CDC reports the significant increases in measles cases so far in 2024, underscoring the need for enhanced vaccination efforts, especially among under-vaccinated communities, and focusing on rapid case detection, control measures, and national vaccination coverage to maintain measles elimination in the US.

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