A 2009 measles outbreak linked to an unvaccinated child who was treated in the emergency department of a hospital in southwestern Pennsylvania highlights both the potential for measles transmission in health care settings and the need for clinicians to include the disease in differential diagnoses of patients with fever and rash. Hospitals should document employees’ immunity and be otherwise prepared to limit outbreaks, according to a report released today by the Centers for Disease Control and Prevention in Morbidity and Mortality Weekly Report.
In March of 2009, a physician report to the Pennsylvania Department of Health of a measles case involving an unvaccinated child – followed within 5 days by reports of four additional reported cases, including three unvaccinated children and one physician, who had been in the same community hospital ED on the same day earlier in the month – led to an electronic medical record review to identify the source patient.
Photo courtesy CDC/Heinz F. Eichenwald
This photo shows the skin of a patient after 3 days of measles infection. A series of measles cases in a Pennsylvania emergency department led to an extensive and expensive regional search and investigation of the approximately 4,000 individuals who had been in contact with all six of the patients during the incubation period.
The source was also a child (the brother of the initially diagnosed patient) who had recently arrived in the United States with his family from India, and who had been treated previously in the ED for a rash diagnosed as viral exanthema and released, the CDC reported (MMWR 2012;61:30-2).
The discovery led to an extensive and expensive regional search and investigation of the approximately 4,000 individuals who had been in contact with all six of the patients during the incubation period. A review of employee health records to identify exposed personnel without serologic evidence of measles immunity was also conducted. The investigation did not identify any additional measles cases, but did identify 72 of 168 potentially exposed employees with no documented measles immunity who were then required to undergo serologic testing and, if necessary, vaccination, according to the report. Testing found that eight did not have measles IgG antibodies, and of those, five were furloughed for 18 days after exposure.
Of note, the authors wrote in an editorial note, "of the six cases, only the index patient initially was suspected of having measles; therefore, he was the only patient for whom isolation precautions were taken," despite 2007 guidelines issued by the Hospital Infection Control Practices Advisory Committee (HICPAC) recommending precautions against airborne transmission for any patient who has a maculopapular rash accompanied by cough, coryza, and fever. The failure to readily identify potential measles cases may be attributable to U.S. clinicians’ limited experience with the contagious disease – itself an unintended consequence of the high U.S. vaccination coverage levels and the efficacy of the measles-mumps-rubella vaccine, they wrote.
In addition to the public health implications, health care–associated measles outbreaks pose a substantial burden on public health resources and health care facilities, in terms of the time and cost of extensive record reviews, contact tracing, and requisite communications, the authors wrote.
Fortunately, the scope of the Pennsylvania outbreak was limited, possibly because of high rates of measles immunization in the community, the fact that the affected children did not attend school or child care, and intense public health control efforts, they stated.
In addition to improving clinicians’ awareness of measles and the necessary isolation procedures, "all health care facilities should follow [Advisory Committee on Immunization Practices] ACIP and HICPAC guidelines that health-care facilities should ensure that their employees are fully vaccinated from measles or have laboratory evidence of immunity," the authors stressed. "This can minimize the need for emergency testing and furlough of employees exposed to measles and associated outbreaks."