The CDC has issued a public health notice to “stay alert” to the threat of measles after clusters of the disease have been found across the United States.

Between December 1, 2023 and January 23, 2024, the agency says it was notified of 23 confirmed US cases of measles, including seven direct importations of measles by international travelers and two outbreaks with more than five cases each.

Most of these cases were among children and adolescents who had not received a measles-containing vaccine (MMR or MMRV), even if age eligible.

Due to the recent cases, healthcare providers should be on alert for patients who have:

  1. febrile rash illness and symptoms consistent with measles (e.g., cough, coryza, or conjunctivitis), and
  2. recently traveled abroad, especially to countries with ongoing measles outbreaks. Infected people are contagious from 4 days before the rash starts through 4 days afterwards.

Measles cases often originate from unvaccinated or undervaccinated US residents who travel internationally and then transmit the disease to people who are not vaccinated against measles. The increased number of measles importations seen in recent weeks is reflective of a rise in global measles cases and a growing global threat from the disease. 

CDC Recommendations for Healthcare Providers

1) Isolate

Do not allow patients with suspected measles to remain in the waiting room or other common areas of the healthcare facility; isolate patients with suspected measles immediately, ideally in a single-patient airborne infection isolation room (AIIR) if available, or in a private room with a closed door until an AIIR is available. Healthcare providers should be adequately protected against measles and should adhere to standard and airborne precautions when evaluating suspect cases regardless of their vaccination status. 

2) Notify

Immediately notify local or state health departments about any suspected case of measles to ensure rapid testing and investigation. Measles cases are reported by states to CDC through the National Notifiable Diseases Surveillance System (NNDSS) and can also be reported directly to CDC at [email protected].

3) Test

Follow CDC’s testing recommendations and collect either a nasopharyngeal swab or throat swab for reverse transcription polymerase chain reaction (RT-PCR), as well as a blood specimen for serology from all patients with clinical features compatible with measles. RT-PCR is available at CDC, at many state public health laboratories, and through the APHL/CDC Vaccine Preventable Disease Reference Centers.

4) Manage

In coordination with local or state health departments, provide appropriate measles post-exposure prophylaxis (PEP) to close contacts without evidence of immunity, either MMR or immunoglobulin. The choice of PEP is based on elapsed time from exposure or medical contraindications to vaccination.

5) Vaccinate

Make sure all your patients are up-to-date on measles vaccine, especially before international travel. People 6 months of age or older who will be traveling internationally should be protected against measles. 


Additional information is available on the CDC’s website.