Measles

Educational Objectives

The goals of this program are to improve the diagnosis of measles. After hearing and assimilating this program, the clinician will be better able to:

1. List the clinical features of measles.

2. Distinguish measles from other diseases with similar symptoms.

3. Provide counseling about the short- and long-term risks associated with measles.

Summary

Background: highly contagious viral illness; near universal infection by adulthood in prevaccine era; humans only host; measles targeted for possible eradication; measles vaccine highly efficacious; immunity resulting from either natural infection or vaccine is durable

Prevaccine era: 3 to 4 million cases annually in United States (≈500,000 cases actually reported); complications included pneumonia (150,000 cases) and encephalitis (4000 cases), which resulted in 50,000 hospitalizations; cases of measles declined dramatically after license of first vaccine in 1960s; slight increase in late 1980s and early 1990s led to second dose in vaccine schedule; in 2000, measles declared eliminated (ie, no endemic transmission observed) in United States

Transmission: 90% of susceptible individuals exposed to measles become infected; mode of transmission airborne; individuals contagious 4 days before onset of rash; individuals at risk for infection if entering airspace occupied by infected individual 1 to 2 hr previously; measles probably most infectious communicable disease (reproductive number [R0] 12-18; R0 for enterovirus 5, severe acute respiratory syndrome 3, and tuberculosis 0.5)

Outbreaks: from 2001 to 2013, 50 to 100 cases of measles occurred annually in United States; 610 cases reported in 2014; most cases in United States related to travelers returning from endemic areas (eg, Africa, Asia, Pacific Rim) that lack resources; concern growing about measles in Europe (due to conscious decision of individuals not to immunize); of 58 cases of measles in California in 2014, 54 directly imported from Philippines, India, Singapore, Vietnam, and Western Europe; genotyping identified B3 (currently circulating in Philippines) in majority of cases

Disneyland: individuals who had visited Disneyland in late 2014 diagnosed with measles in early 2015; genotyping identified B3 in 95% of cases; outbreak declared over in April 2015; highest incidence (per 100,000 population) observed in infants <1 yr of age (age group that cannot be vaccinated); most older individuals for whom vaccination status was known were found to be unvaccinated, and many of these individuals had consciously chosen not to be vaccinated; among vaccinated individuals, 10 received 1 dose, 13 received 2 doses, and 2 received 3 doses (small number of individuals fail to respond to vaccine); pockets of unvaccinated individuals led to clusters of infections

Clinical features: incubation period averages 8 to 12 days (but can be as long as 21 days); individuals not infectious during incubation period; infectious period starts with fever and 3 Cs (cough, coryza, conjunctivitis); rash starts ≈4 days later on face and around hairline, then spreads to trunk and extremities; course of disease predictable; Koplik spots — pathognomonic for measles; tiny white spots located on buccal mucosa or behind molars; erythematous, maculopapular rash — later becomes confluent; persists 5 to 6 days; fades in order in which it appeared

Other forms of measles: modified measles — occurs in individuals with partial immunity; symptoms similar to those of measles, but milder (reduced fever, shorter prodrome, nonconfluent rash, and absence of Koplik spots); atypical measles — different syndrome; rash starts on extremities; most often linked to inactivated vaccine administered from 1963 to 1976

Complications during acute period: rate of hospitalization ≤30%; rate of pneumonia ≤25% depending on age and risk status; acute encephalitis affects 1 in 1000 patients; overall mortality rate 0.1% to 0.3%; increasingly severe outcomes observed in immunocompromised patients (eg, during pregnancy); rates of pneumonia and hospitalization decreased in individuals 5 to 19 yr of age

Subacute sclerosing panencephalitis: long-term complication; associated with high rate of mortality and poor quality of life; affects 1 in 1700 patients <5 yr of age

Laboratory: serologic testing unreliable; polymerase chain reaction (PCR) assay highly sensitive and specific

Treatment: no specific antiviral treatment exits; World Health Organization (WHO) recommends vitamin A

Prevention: vaccine highly efficacious, but high immunization rates required to prevent transmission; infection control — suspected cases should be kept out of office, be seen at end of day, and wear mask

Global impact: measles leading cause of pediatric mortality worldwide (145,000 deaths in 2013)

Questions and Answers

Kawasaki disease: differential diagnosis should include Rocky Mountain spotted fever and enterovirus; predictable onset of cough, coryza, conjunctivitis, and facial rash suggestive of measles; maintain index of suspicion for measles; limbic sparing does not occur with measles; anterior uveitis present with Kawasaki disease; adequate history of illness progression key to accurate diagnosis; laboratory tests helpful

Management of individuals who fail to seroconvert after 2 doses of measles vaccine: state laboratory testing often more sensitive than commercial laboratory testing for detection of antibody

Readings

Diel R et al: Evidence-based comparison of commercial interferon-gamma release assays for detecting active TB: a metaanalysis. Chest, 2010 Apr;137(4):952-68; Diel R et al: Negative and positive predictive value of a whole-blood interferon-γ release assay for developing active tuberculosis: an update. Am J Respir Crit Care Med, 2011 Jan;183(1):88-95; Ewer K et al: Comparison of T-cell-based assay with tuberculin skin test for diagnosis of Mycobacterium tuberculosis infection in a school tuberculosis outbreak. Lancet, 2003 Apr;361(9364):1168-73; Halsey NA, Salmon DA: Measles at Disneyland, a problem for all ages. Ann Int Med, 2015 May 5;162(9):655-6; Mandalakas AM et al: Interferon-gamma release assays and childhood tuberculosis: systematic review and meta-analysis. Int J Tuberc Lung Dis, 2011 Aug;15(8):1018-32; Pai M et al: Systematic review: T-cell-based assays for the diagnosis of latent tuberculosis infection: an update. Ann Int Med, 2008 Aug;149(3):177-84; Perry RT, Halsey NA: The clinical significance of measles: a review. J Infect Dis, 2004 May;189 Suppl 1:S4-16; Seither R et al: Vaccination coverage among children in kindergarten — United States, 2013-14 school year. MMWR Morb Mortal Wkly Rep, 2014 Oct 17;63(41):913-20; Silverman RD, Hendrix KS: Point: Should childhood vaccination against measles be a mandatory requirement for attending school? Yes. Chest, 2015 Jun;[Epub ahead of print]; Starke JR, Cruz AT: The global nature of childhood tuberculosis. Pediatrics, 2014 Mar;133(3):e725-7; Warraich HJ: The measles outbreak coming near you. Mo Med, 2015 Mar-Apr; 112(2):104-5; Wolfson LJ et al: Estimates of measles case fatality ratios: a comprehensive review of community-based studies. Int J Epidemiol, 2009 Feb; 38(1):192-205.

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, members of the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Glaser was recorded at the 48th Annual Advances and Controversies in Clinical Pediatrics, held May 28-30, 2015, in San Francisco, CA, and presented by the University of California, San Francisco, School of Medicine and UCSF Benioff Children’s Hospital. For information about upcoming CME activities from the University of California, San Francisco, School of Medicine, please visit cme.ucsf.edu. The Audio Digest Foundation thanks the speakers and the University of California, San Francisco, School of Medicine for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

PD613601

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.