California Public Health officials announced Tuesday that they are investigating the potential for a measles outbreak at Yuba River Charter School in Nevada County, California, after an elementary school student was diagnosed with measles following a trip overseas. The California Department of Public Health confirmed that the child has fully recovered, but worried that other students at the child’s school had been exposed to the virus.
The elementary school did reopen Wednesday, but only for children who were up-to-date on their vaccinations. Unfortunately, 55 percent of the student body was ineligible to attend school the next day, because, according to school records, 124 students (out of 225 present the day before) lacked the proper vaccination against measles. Last year, school records reported that only 43 percent of the student body was properly vaccinated, leading the California Department of Public Health to classify the school as “most vulnerable” to an outbreak.
Since not every child is medically able to be vaccinated, it is important for the public to achieve herd immunity, which has been shown to be effective at preventing the spread of disease. However, herd immunity is only effective when 95 percent of a population is vaccinated. As the numbers above indicate, Yuba River Charter School was far from reaching this threshold, which might have prevented the risk of an outbreak.
Despite the widespread medical consensus that vaccines do not cause autism and are highly effective at preventing diseases, many parents still opt out of vaccinating their children. As a result, measles has been on the rise in recent years, as parents increasingly repudiate the medically sound practice.
Dr. Karen Smith, of the California Department of Public Health, reminded parents in a statement released Tuesday that “immunization is the best way to protect against measles. Two doses of the Measles, Mumps, and Rubella vaccine are approximately 97 percent effective at preventing disease in exposed persons.” The World Health Organization estimated that measles vaccinations have saved 17.1 million lives worldwide between 2000 and 2014.
Unfortunately, California is already familiar with recent, and preventable, outbreaks of measles. Last year, public health officials reasoned that a measles outbreak at Disneyland was the direct result of low vaccination rates among park visitors. After last year’s outbreak at Disneyland, California lawmakers moved to make opting out of the vaccination process more difficult for parents. The resulting law, signed by California Governor Jerry Brown, transformed California into one of the strictest states in terms of vaccination enforcement.
Measles is one of the world’s most infectious viruses, and common symptoms include high fever, conjunctivitis, and a distinctive rash. In severe cases, measles can result in more serious symptoms, or even death.
Bryan Dewan is an Intern at ThinkProgress.