In the decade after measles was largely eradicated in the United States in 2000, the number of reported cases of the highly contagious disease hovered around 60 each year.
But since 2010, the annual number has shot up to 155, according to the Centers for Disease Control and Prevention. And in just the first three months of 2014, 106 cases have been reported across the country. Health officials are worried.
CDC issued a travel warning last month after several unvaccinated children returned to the states with measles infections from the Philippines, where the disease is still relatively common. Among physicians, some pediatric infectious-disease specialists have begun pleading with the American public to vaccinate their children.
Measles is an airborne viral infection that affects the skin and respiratory and immune systems, starting with a rash and high fever. It can be prevented with a blanket vaccination that also protects against mumps and rubella. Before widespread vaccination efforts took root in 2000, the U.S. saw about 500,000 measles cases each year, which led to 48,000 hospitalizations and 500 deaths.
Right now, two outbreaks are slowly spreading on opposite sides of the country. In New York City, thenumber of reported cases in an outbreak that began in February rose to 26 last week. In California, 49 measles cases have been reported this year, compared with four at this time last year.
Most current measles cases have been linked to foreign sources, such as the Philippines. But the rate of U.S. parents choosing not to vaccinate their children has increased in recent years, resulting in a higher incidence of the illness. More than 90 percent of young children are vaccinated against measles in the U.S., but laws requiring immunization for schoolchildren vary by state.
California is one of 19 states that allows parents to opt out of immunizations for young schoolchildren on the basis of personal beliefs. In these states, the rate of unvaccinated children is higher. And when unvaccinated children are clustered in one region, the risk of an outbreak from an imported infection is higher. New York does not allow such an exemption.
A considerable chunk of American physicians, especially young ones, have not seen measles because of its virtual elimination 14 years ago. But as the number of reported cases continues to climb, that will likely change. And it's only April.
For more information about measles and its prevention, visit cdc.gov/measles.