Once eliminated in the U.S., measles threatens to reclaim endemic status

March 18th, 2015

California public health officials reported the state measles outbreak reached 92 cases as of Feb. 2, with 59 of those epidemiologically linked to Disneyland theme park in Orange County. In separate figures, the Centers for Disease Control and Prevention reported that as of Jan 30^th there were 102 people from 14 states infected. The California outbreak reflects the majority of those cases, but the CDC is concerned that a nation that was once declared measles free could once again face an endemic, highly transmissible virus that can seriously threaten high risk patients.

“It's only January and we have already have a very large number of measles cases – as many cases as we have all year in typical years,” Anne Schuchat, MD, director of CDC’s National Center for Immunization and Respiratory Diseases said at a recent press conference. “This worries me and I want to do everything possible to prevent measles from getting a foothold in the United States and becoming endemic again. I want to make sure that parents who think that measles is gone and haven't made sure that they or their children are vaccinated are aware that measles is still around and it can be serious and that MMR vaccine is safe and effective and highly recommended.”

An anti-vaccine movement has formed claiming the MMR is linked to autism. The premise has been thoroughly debunked by several gold standard studies, but the damage was done in 1998, when the British journal The Lancet infamously published a since-retracted “study” that fueled fears that the MMR vaccine may cause autism in children. The article was retracted by the journal in 2010 after years of controversy and criticism from the medical community. Still, parents in various pockets and communities still refuse to have their children immunized, compounding the problem of imported cases from countries where measles is still spread in the community. Though declared eliminated in the U.S. in 2000, measles is still widespread in many parts of the world, including Europe, Africa, and Asia.

The primary risk group in the current U.S. outbreak is those who have not been vaccinated, particularly infants less than a year old. This group would not be indicated yet for the MMR (measles, mumps, rubella) shot, which is typically given in two doses beginning when a child is 12 to 15 months old. The second dose of MMR is given between 4-6 years of age.

“Measles is highly contagious and highly preventable through vaccinations,” said Gil Chavez, MD, California State Epidemiologist. “Any place where large numbers of people congregate and there are a number of international visitors, like airports, shopping malls and tourist attractions, you may be more likely to find measles, which should be considered if you are not vaccinated. It is safe to visit these places, including the Disneyland Resort, if you are vaccinated.”

The outbreak started in December 2014 when at least 40 people who visited or worked at Disneyland theme park in Orange County in mid-December contracted measles. Diagnosis has been a problem in some cases, as many physicians have rarely seen measles. The infection begins with a fever that lasts for a couple of days, followed by a cough, runny nose, conjunctivitis, and the classic rash. The rash typically appears first on the face, along the hairline, and behind the ears and then affects the rest of the body. Infected people are usually contagious from about 4 days before their rash starts to 4 days afterwards.