Imported measles only a plane ride away

February 2, 2012

Measles outbreaks are at their worst level in more than a decade, with almost all transmissions caused by imported cases. The Centers for Disease Control and Prevention advises on steps clinicians can take to keep an imported measles case from transmitting to an outbreak.

Measles cases in the United States most often are imported. There were more than 200 cases of measles reported in the United States in 2011, the worst level in more than a decade, with nearly 90% of them linked to travelers returning from or visiting from other countries.

Domestic Measles transmissions have been virtually halted, or were until recently when many parents stopped having their children vaccinated because of unfounded fears about the measles-mumps-rubella (MMR) vaccine. However, recent data from the Centers for Disease Control and Prevention (CDC) show more than 26,000 cases of measles being reported across Europe and more than 125,000 cases in Africa.

To prevent imported measles from becoming outbreaks, the CDC is advising that providers ensure they have documented laboratory immunity to measles and that clinicians include measles in the differential diagnosis of patients with fever and rash, especially among patients with recent international travel.

The frequency of imported measles among children aged 6 to 23 months suggests that parents and clinicians might not be aware of recommendations to administer MMR vaccine to children as young as 6 months when they are living or traveling abroad.

Measles often is not considered in the initial differential diagnosis of children returning from international travel with a rash illness; as a result, diagnosis of measles frequently is delayed. That happened in a 2009 hospital-based outbreak, which has been investigated and the findings cited in a CDC report.

In that case, a child who had recently arrived in Pennsylvania from India was brought to a hospital emergency department (ED) with a rash that was diagnosed as a viral exanthema. The child was not isolated. Subsequently, 1 ED physician and 4 visitors to the ED, including 3 unvaccinated children, were diagnosed with measles in the next 3 weeks.

Of 168 hospital employees, 72 (43%) did not have measles IgG titers on record. Of the 69 employees who subsequently were tested, 8 (12%) did not have measles IgG antibodies.

The outbreak highlights the potential for measles transmission in health care settings. To decrease transmission, clinicians should know the signs and symptoms of measles, request travel histories of patients suspected of any infectious disease, and isolate potentially infectious patients.

Go back to the current issue of the eConsult.