Top 5 Takeaways

  1. Significant Increase in Cases Early 2024: There was a dramatic rise in reported measles cases in the first quarter of 2024, with 97 new cases accounting for 29% of all cases since January 2020.
  2. High Number of Unvaccinated Cases: The majority of measles cases (91%) were in unvaccinated individuals or those with unknown vaccination status, emphasizing ongoing vulnerability in certain populations.
  3. Import-Associated Cases Predominate: Nearly all reported cases (96%) were associated with importation, highlighting the global interconnectedness and risk of measles introduction from abroad.
  4. Effective Surveillance Maintains Elimination Status: The absence of endemic measles transmission for over 12 months, alongside a well-performing surveillance system, allowed the U.S. to maintain its measles elimination status as of the end of 2023.
  5. Need for Increased Vaccination Efforts: There is a critical need to boost MMR vaccination coverage, particularly in undervaccinated communities and before international travel, to sustain elimination efforts and reduce the risk of outbreaks.

Original Article Author and Citation

Corresponding Author

Adria D. Mathis, MSPH,

Suggested Citation

Mathis AD, Raines K, Masters NB, et al. Measles — United States, January 1, 2020–March 28, 2024. MMWR Morb Mortal Wkly Rep 2024;73:295–300. DOI:


The report reviews measles cases in the U.S. from January 1, 2020, to March 28, 2024, emphasizing the maintenance of the U.S. measles elimination status despite ongoing challenges. It notes a significant spike in measles cases in early 2024, mainly among unvaccinated individuals or those with unknown vaccination status.


The CDC’s analysis involved epidemiologic and laboratory surveillance data to track measles cases, categorize them by source, and assess the performance of the national measles surveillance system.


The discussion underscores the role of high national measles vaccination coverage and robust surveillance in maintaining measles elimination in the U.S. It also highlights the risks posed by decreasing global vaccination rates and the necessity of preparedness against potential outbreaks.


Maintaining high levels of vaccination coverage is crucial for continuing to prevent measles outbreaks in the U.S. The increase in measles cases in early 2024 is a reminder of the constant need for vigilance and proactive public health strategies.

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