CAUSED BY A PARAMYXOVIRUS, measles is a highly contagious acute viral infection most often spread via respiratory droplets. Infection occurs more often during late winter and spring. Measles was once a common childhood illness until the measles vaccine was licensed for use in 1963. The infection is rare in the United States, but undervaccination has led to outbreaks in recent years. In 2008, 140 measles cases were reported in San Diego, the largest number since 1996. All of the children who contracted the illness were intentionally not vaccinated for measles. Rising undervaccination rates, caused by parents who believe the vaccines are harmful, can lead to outbreaks of vaccine-preventable diseases such as measles.1 Outbreaks can also occur among adults, such as on college campuses.
Measles is still a common and often fatal infection in developing countries, with an estimated 10 million cases reported annually, most of them from Africa.2 Travelers and immigrants from developing countries can introduce the infection into a community.
You may be the first clinician to assess a patient with measles, so make sure you're familiar with the signs and symptoms.
Recognizing signs and symptoms
Measles, also known as rubeola, typically begins 7 to 14 days after exposure with fever, cough, rhinitis, conjunctivitis, and pharyngitis. Two or 3 days after signs and symptoms begin, Koplik spots (small blue-white spots) may appear on the buccal mucosa. Three or 5 days after the start of signs and symptoms, an erythematous and maculopapular rash appears, typically starting on the face and spreading down to the neck, trunk, and extremities.3
About 30% of patients develop complications, including encephalomyelitis, pneumonia, and otitis media. Complications are more common in children under age 5 and adults age 20 and older. Pneumonia accounts for about 60% of all measles deaths.4
The incubation period from exposure to onset of signs and symptoms ranges from 8 to 12 days. Immunocompromised patients may be contagious throughout the course of illness.5
Measles is usually diagnosed based on the patient's clinical presentation, but blood work may be needed to confirm the diagnosis.
The measles virus sandwich-capture immunoglobulin M (IgM) antibody assay is the quickest test to confirm measles. Blood samples for measles-specific IgM can be obtained on the third day of the rash or any subsequent day up to 1 month after onset.4
Because it's so highly communicable, measles is a CDC Nationally Notifiable Infectious Disease Surveillance System reportable infection.
Treatment and prevention
To prevent disease spread, the CDC recommends airborne precautions for 4 days after the onset of rash, and for the duration of the illness in immunocompromised patients. Treatment is supportive: rest, fluids, and proper nutrition. Antimicrobial therapy is indicated for patients with secondary infections.6 Vitamin A supplements have been associated with decreased morbidity and mortality and are recommended for certain patients, including children with immunodeficiency.5
To prevent measles, the MMR (mumps, measles, and rubella) or MMRV (mumps, measles, rubella, and varicella) vaccines are given in two doses: one at age 12 to 15 months and another at age 4 to 6 years. The MMRV vaccine can be used in children age 12 months through 12 years. Adults should get the MMR vaccine if they were born after 1956 unless they have already had measles.7
The MMR and MMRV vaccines are contraindicated in patients who are pregnant or may become pregnant within 4 weeks, patients with severe immunodeficiency, such as severely symptomatic HIV, and those with a history of anaphylaxis triggered by the vaccines or any of their components. Advise patients that risks such as allergic reactions can occur with the MMR and MMRV vaccines, but getting the vaccine is much safer than getting measles.7
1. Sugerman DE, Barskey AE, Delea MG, et al. Measles outbreak in a highly vaccinated population, San Diego, 2008: role of the intentionally undervaccinated. Pediatrics
4. Centers for Disease Control and Prevention. Measles. Epidemiology and Prevention of Vaccine-Preventable Diseases. 11th ed. Washington DC: Public Health Foundation; 2009:157–164.
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