Measles: A dangerous vaccine-preventable disease returns

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The diagnosis of measles is straightforward when all of the signs and symptoms are present. In partially vaccinated populations, however, the diagnosis may need to be confirmed by serologic or polymerase chain reaction (PCR) testing.

Differential diagnosis

The differential diagnosis of the fever and a rash typical of measles in children, especially when accompanied by severe malaise, includes the following:

Kawasaki disease. However, the red eyes of Kawasaki are an injection of the bulbar conjunctivae with sparing of the limbus. No eye exudate is present, and respiratory illness is not part of the disease.

Drug eruptions can present with a morbilliform rash and sometimes fever, but not the other signs of measles in either adults or children.

Scarlet fever has a different rash, the sandpaper rash typical of toxin-mediated disease.

Rubella tends to cause mild respiratory symptoms and illness rather than the severe disease of measles and other rash-causing viral infections in children and infants.

Confirmation in confusing cases

To confirm a diagnosis of measles, samples from throat, nasal, and posterior nasopharyngeal swabs should be collected with a blood specimen for serology and sent to the state public health laboratory.4 The US Centers for Disease Control and Prevention gives instructions on who should be tested and with which tests.4

Most testing now uses PCR for viral RNA, as viral culture is more costly and takes longer. For accurate diagnosis, samples for PCR must be obtained during the acute illness.

The serologic gold standard for diagnosis is a 4-fold rise or fall in immunoglobulin G (IgG) titer of paired serum samples sent 10 days to 2 weeks apart around the illness. The IgM test may be negative initially, and a negative test cannot be used to rule out the diagnosis. Confirmed cases should be reported to public health authorities.


Frequent complications of measles infection include those related to the primary viral infection of respiratory tract mucosal surfaces, as well as bacterial superinfections. Complications are most likely in children under age 5, nonimmune adults, pregnant women, and immunocompromised people. Typical complications include otitis media, laryngotracheobronchitis (presenting as a croupy cough), pneumonia, and diarrhea.

Late sequelae of measles infection are related in part to serious mucosal damage and generalized immune suppression caused by the virus. Even after recovery from acute infection, children can have persistent diarrhea and failure to thrive, with increased mortality risk in the months after infection. Tuberculosis can reactivate in patients already infected, and new tuberculosis infection can be especially severe. Further, tuberculosis skin tests become less reliable immediately after measles infection. Severe disease and fatalities are increased in populations that have baseline vitamin A deficiency and malnutrition.

Death from measles is most often caused by viral pneumonia, secondary bacterial pneumonia, and postviral encephalitis. Before the vaccine era, measles encephalitis occurred in the United States in about 1 in 1,000 measles cases.

Subacute sclerosing panencephalitis is a rare, late, and often fatal complication of measles that presents 7 to 10 years after acute measles infection, usually in adolescence. Beginning with myoclonic jerks, stiffening, and slow mental deterioration, it progresses over 1 to 3 years, with a relentless degenerative course leading to death. Since the introduction of the measles vaccine in 1957, this disease has essentially disappeared in the United States.


Management of measles and its complications is primarily supportive.

Table 1. Vitamin A for acute measles infection: WHO recommendations
Vitamin A should be given to all children with acute disease to decrease the risk of complications, including blindness and death (Table 1). Most likely, adults with acute infection should also get vitamin A, though there are no data to support or refute the recommendation in this population.5

Preventing contagion

Measles infection has an incubation period of 8 to 12 days. Individuals are contagious 4 days before to 4 days after rash onset in the normal host but longer in those lacking immune function. Cases can occur up to 21 days after exposure during the contagious period.

The disease is highly contagious, so hospitalized patients should be cared for with airborne precautions. It is crucial that caretakers be vaccinated properly, so that they can care for patients safely. Recommendations for preventing secondary cases by prompt vaccination and giving immune globulin are detailed below, including specific recommendations for individuals with immune system suppression.

The current US public health policy regarding measles vaccine booster doses began in response to the widespread measles outbreak in the United States from 1989 to 1991. Cases occurred more commonly in unvaccinated individuals and in young adults who had received only 1 dose of vaccine.

Today, the policy in areas where measles has been controlled is to vaccinate between 12 and 15 months of age and to boost with a second dose before starting kindergarten. In outbreak situations, the first dose should be given at 6 months of age, with a repeat dose at 12 to 15 months of age and the usual booster before starting kindergarten.

Table 2. MMR vaccination: CDC recommendations
Most adults born in the United States between 1957 and 1989 received only 1 dose of measles vaccine, and a single dose confers immunity for most but not all. Accordingly, if such an individual is traveling or living in an endemic area (eg, India, Brazil, Brooklyn, NY), then a booster is recommended without checking a titer (Table 2).
Table 3. CDC criteria for evidence of immunity to measles
Anyone born after 1989, if vaccinated appropriately, has received 2 doses of measles vaccine; thus, there is no need for booster doses or titers. In fact, titers are not recommended in most people because of the high rate of false-negative results and because there is no harm in receiving an extra dose of the measles-mumps-rubella (MMR) vaccine (it can actually boost immunity).6 Healthcare institutions check titers in employees for patient safety.

Those born before 1957 can be presumed to have had natural measles, which confers lifelong immunity (Table 3).7

Next Article:

The return of measles—an unnecessary sequel

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