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Measles outbreak linked to Disney theme parks reaches five states and Mexico

BMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h436 (Published 23 January 2015) Cite this as: BMJ 2015;350:h436
  1. Michael McCarthy
  1. 1Seattle

California’s Department of Public Health is warning anyone who has not been vaccinated against measles or who is unsure of their vaccination status to stay away from two Disney theme parks in Anaheim—Disneyland and Disney California Adventure Park—after scores of cases have been linked to the popular tourist destinations.

Officials said that since the end of December 59 cases of measles have been confirmed among California residents, 42 of which have been linked to initial exposure at the two parks. Five of the confirmed cases were in Disney employees. Some cases, however, have not been linked epidemiologically to the Disney exposures. The ages of the people infected in California have ranged from 7 months to 70 years. A quarter of them have required admission to hospital but there have been no deaths.

Additional cases related to the outbreak have been reported in four other states: Utah, which has two primary and one secondary case; Washington, which reports one primary case and one secondary case; and Colorado and Oregon, which both report one primary case. Mexico has also reported one case. Overall, to date, more than 70 cases have been linked to or are suspected to be related to the outbreak, California officials said.

The US Centers for Disease Control and Prevention said that people infected with measles are usually contagious for about nine days, from about four days before they develop their rash until several days after. The virus is easily spread by coughing and sneezing and remains infectious on surfaces for up to two hours.

Measles was declared eliminated in the United States in 2000, but outbreaks occur when travelers from countries where measles continues to circulate visit the US or when US residents contract the virus abroad and return home while contagious. California health officials said that they will probably never know how the virus responsible for the current outbreak entered the country.

In recent years the number of cases in the US has been on the rise, mostly resulting from large outbreaks abroad, particularly in western Europe, Pakistan, Vietnam, and the Philippines, and increases in the number of infected travelers entering the country. Outbreaks have also occurred in some US communities that forgo vaccination.

In a press conference Gil Chavez, state epidemiologist for California, said that 28 (82%) of the 34 infected people in California whose vaccination status was documented were unvaccinated. Six were too young to be vaccinated, and the rest had intentionally not been vaccinated. Another person had received one of the doses of the measles, mumps, and rubella vaccine, and five had received two or more doses.

The best protection against measles is a two dose regimen of the MMR vaccine, which is safe and more than 99% effective, Chavez said. He strongly urged anyone who was unvaccinated to get the vaccine “to protect themselves, their loved ones, and the community at large.”

Complications of measles can include pneumonia, neurologic involvement, and death. The CDC said that about one in 1000 people with measles will develop meningitis and about one in 1000 will die. “Measles is not a trivial illness,” Chavez said. “Measles can be very serious, with devastating complications.”

Notes

Cite this as: BMJ 2015;350:h436

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