The Delaware Division of Public Health (DPH) is issuing this health advisory  to notify clinicians of a measles exposure at the Nemours Children’s Hospital emergency department in Wilmington on February 18, 2026.

Summary
On February 20, 2026, DPH received positive laboratory test results for measles in an unvaccinated individual. The individual is a resident of another state who sought treatment at a Nemours Children’s Hospital on February 18, 2026, while infectious. Contact tracing is ongoing, and DPH, in partnership with Nemours Children’s Hospital, has identified and contacted the individuals who were present at the Emergency Department during the time of exposure. This health advisory also highlights the increased incidence of measles in the United States and the importance of early detection, diagnosis, and appropriate treatment. The Centers for Disease Control and Prevention (CDC) and DPH recommend that clinicians be on alert for cases of measles that meet the case definition.

Background
Measles is a highly contagious, acute viral illness that begins with a prodrome of fever, cough, coryza (runny nose), and conjunctivitis (pink eye), lasting two to four days prior to rash onset. 

The rash typically occurs three to five days after symptoms begin and usually appears on the face and spreads down the body. Measles can cause severe health complications, including pneumonia, encephalitis (brain inflammation), and death. The virus is transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. Measles virus can remain infectious in the air and on surfaces for up to two hours after an infected person leaves an area. Infected people are contagious from four days before the rash starts through four days after rash development. The incubation period for measles from exposure to fever is usually about 10 days (range, seven to 12 days), and from exposure to rash onset is usually about 14 days (range, seven to 21 days).

In 2025, 2,281 confirmed measles cases were reported to the CDC by 45 states. As of February 20, 2026, 982 cases have been reported since January in 26 states. Cases in 2025 and 2026 are substantially higher than those reported during 2024, during which 285 cases were reported the entire year in 31 states and the District of Columbia. As of February 26, 2026, there have been no measles cases identified in Delaware, but DPH reminds clinicians to be on alert. 

Health care professionals (HCPs) are recommended to:
•    Consider measles as a diagnosis in anyone with febrile illness and clinically compatible symptoms (e.g. rash, cough, coryza, or conjunctivitis) who has recently traveled abroad or to outbreak regions.
•    Immediately notify DPH about any suspected case of measles to ensure rapid testing and investigation. Contact the Office of Infectious Disease Epidemiology (OIDE) during regular business hours (302-744-4990) or the state’s 24-hour reporting line at 1-888-295-5156 outside of normal business hours. 
•    Recommend MMR vaccine for patients who are unvaccinated or not fully vaccinated. 
•    Do not allow patients with suspected measles to remain in the waiting room or other common areas of the health care facility; isolate patients with suspected measles immediately, ideally in a single-patient airborne infection isolation room (AIIR), if available. If an AIIR is not available, isolate patients in a single-patient room with a closed door. 
•    Follow CDC’s testing recommendations and collect either a nasopharyngeal swab or urine specimen 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 many state public health laboratories and through the APHL/CDC Vaccine Preventable Disease Reference Centers. 
•    Ensure all patients are up to date on MMR vaccine and other recommended vaccines. 
•    For people traveling abroad, CDC recommends that all U.S. residents older than six months be protected from measles and receive MMR vaccine, if needed, prior to departure. 

If you suspect patient exposure, either administer MMR vaccine within 72 hours of initial measles exposure or immunoglobulin (IG) within six days of exposure. The MMR vaccine and IG provide post-exposure prophylaxis (PEP) to prevent measles or modify the clinical course of disease among susceptible people. For vaccine eligible people aged ≥12 months exposed to measles, administration of MMR vaccine is preferable to using IG, if administered within 72 hours of initial exposure. The following patient groups are at risk for severe disease and complications from measles and should receive IG: infants aged <12 months, pregnant women without evidence of measles immunity, and severely immunocompromised people. IG can be administered to other people who do not have evidence of measles immunity, but priority should be given to people exposed in settings with intense, prolonged, close contact (e.g., household, daycare, and classroom). Do not administer MMR vaccine and IG simultaneously, as this practice invalidates the vaccine.

Testing
Real-time RT-PCR (rRT-PCR): Nasopharyngeal swabs for PCR testing are preferred over urine specimens. PCR specimens can be requested to be tested at the Delaware Public Health Laboratory (DPHL). Contact OIDE  during regular business hours (302-744-4990) or the state’s 24-hour reporting line at 1-888-295-5156 outside of normal business hours to request approval for testing at the DPHL. 

For serology, collect the first (acute phase) serum specimen (IgM and IgG) as soon as possible upon suspicion of measles disease. If the acute-phase serum specimen collected ≤3 days after rash onset is negative and the case has a negative result for real-time RT-PCR (rRT-PCR), or one was not done, a second serum specimen collected three to 10 days after symptom onset is recommended because the IgM response may not be detectable until 3 days after symptom onset. As of February 2026, serology testing is not currently available at DPHL, but DPHL may be able to facilitate testing through a partner, if needed.   

HCPs should use respiratory protection (i.e., a respirator), that is at least as protective as a fit-tested, NIOSH-certified disposable N95 filtering facepiece respirator, regardless of presumptive evidence of immunity, upon entry to the room or care area of a patient with known or suspected measles.

Reporting
Delaware physicians, laboratories, and other health care providers are required by regulations 
to report patients with measles to OIDE immediately upon identification. Do not wait for test results to be available to contact OIDE. Early reporting enables appropriate public health follow-up for your patients, helps identify outbreaks, and provides a better understanding of disease trends in Delaware. Cases can be reported to OIDE by calling 302-744-4990 (normal business hours) or 1-888-295-5156 (outside of normal business hours). Urgent notification by phone is preferred. You may also complete a Notifiable Disease Report PDF Form and fax the form to DPH at 302-622-4149 or email to: mreportdisease@delaware.gov. The form can be found online at: https://dhss.delaware.gov/dph/homepage/about/sections/ehdishome/epi/report-disease/

For more information 
–    Clinical Overview of Measles
–    Interim Infection Prevention and Control Recommendations for Measles in Healthcare Settings
–    Plan for Travel – Measles
–    Laboratory Testing for Measles
–    Measles Serology Testing