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Increased Incidence of Measles in United States, Recommendations for Health Care Providers


The Centers for Disease Control and Prevention (CDC) released a Health Advisory on March 18, 2024, to call attention to an increase in measles incidence in the United States and abroad. Measles activity in the United States continues to increase. On April 12, 2024, the Nevada Office of State Epidemiology (OSE) was notified of a patient with measles who had visited Las Vegas while infectious. The Southern Nevada Health District issued press releases on April 12 and April 15 containing details of this exposure event.

Health care providers should consider measles as a diagnosis for unvaccinated or under-vaccinated individuals of all ages with a febrile rash, especially those who have a recent exposure or travel. To prevent spread, it is critical that health care providers promptly recognize, isolate and test patients who might have measles. Health care providers must report suspected and confirmed cases of measles to public health authorities within 24 hours.


Measles is a highly contagious viral illness and can cause severe health complications, including pneumonia, encephalitis and death, especially in unvaccinated populations. Measles typically begins with a prodrome of fever, cough, coryza and conjunctivitis, lasting 2 to 4 days before rash onset. The incubation period for measles from exposure to fever is usually about 10 days, with a range of 7–12 days, while rash onset is typically visible around 14 days after initial exposure with a range of 7–21 days. The virus is transmitted through direct contact with infectious droplets or by airborne spread when an infectious person breathes, coughs or sneezes, and can remain infectious in the air and on surfaces for up to 2 hours. Individuals infected with measles are contagious from 4 days before the rash starts through 4 days afterward (the day of rash onset is considered day zero).1

Measles is almost entirely preventable through vaccination. MMR vaccines are safe and highly effective, with two doses being 97% effective against measles (one dose is 93% effective).1

In the United States from Jan. 1 to April 18, 2024, there have been 125 cases of measles in 17 states. Eighty- three percent of these cases were not vaccinated or had unknown vaccination status.2

Recommendations for health care providers

Ensure adequate vaccination to protect patients and prevent spread.

Health care providers should offer MMR (measles, mumps, rubella) vaccine in accordance with CDC recommendations. CDC recommends MMR vaccine for all children and for adults without presumptive evidence of immunity, including international travelers and health care providers.3

Recognize measles and respond quickly

Consider measles as a diagnosis in anyone with fever (≥101˚F or 38.3˚C) and a generalized maculopapular rash with cough, coryza or conjunctivitis who has recently travelled, especially in areas with ongoing outbreaks.

If measles is suspected:

  • Isolate: Do not allow patients with suspected measles into common areas of a health care 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.
    • Call ahead to ensure immediate isolation for patients referred to hospitals for a higher level of care. Always use the DPBH Interfacility Transfer Form when transferring patients with infectious diseases, including measles, to another facility.
  • Health care providers should be adequately protected against measles and should adhere to standard and airborne precautions when evaluating suspect cases, regardless of their vaccination status.
    • Health care providers without evidence of immunity should be excluded from work from day 5 after the first exposure until day 21 following their last exposure.
  • Offer testing outside of facilities to avoid transmission in health care settings.
  • Notify: Within 24 hours, notify the local health authority for your area about any suspected or confirmed cases of measles (NAC 441A.225).
Local Health AuthorityCountyPhone Number to Report
Carson City Health and Human Services (CCHHS)Carson City, Douglas, and Lyon(775) 887-2190 (24 hours)
Central Nevada Health District (CNHD)Churchill, Mineral, Eureka, and Pershing(775) 866-7535 (24 hours)
Northern Nevada Public Health (NNPH, formerly WCHD)Washoe(775) 328-2447 (24 hours)
Southern Nevada Health District (SNHD)Clark(702) 759-1300 (24 hours)
Nevada Division of Public and Behavioral Health (DPBH) Office of State Epidemiology (OSE)  All other counties(775) 684-5911 (M-F 8 a.m. – 5 p.m.) (775) 400-0333 (after hours)
  • Test: Follow CDC’s testing recommendations and collect either a nasopharyngeal swab, throat swab and/or urine for reverse transcription polymerase chain reaction (RT-PCR) and a blood specimen for serology from all patients with clinical features compatible with measles.
    • Measles PCR can be performed at the Nevada State Public Health Laboratory with coordination through the public health authority.
  • Manage: Exposed close contacts without evidence of immunity should be offered post-exposure prophylaxis (PEP) as soon as possible after exposure. This should be done in coordination with the local health authority and the Nevada Division of Public and Behavioral Health. The choice of PEP is based on elapsed time of exposure or medical contraindications to vaccination, but may include MMR (within 72 hours) or immunoglobulin (within 6 days).1 MMR vaccine and IG should not be administered simultaneously, as this invalidates the vaccine.4

Additional Resources

Measles (Rubeola) | CDC

Measles – Nevada Public Health | The Office of State Epidemiology (


For updated guidance, review the Division of Public and Behavioral Health Technical Bulletin web page regularly. Email for other questions regarding measles.