By late January 2015, a measles outbreak that originated when an infected person visited Disneyland in southern California, had spread to more than 67 people in six states and Mexico . So far, more than 20 people had been hospitalized and public health officials were scrambling to halt further spread.
The overwhelming majority of those infected were unvaccinated either by choice or because they were too young to receive the vaccine. Typically, children receive the first dose of measles vaccine between 12 and 18 months of age and the second dose between 4 and 6 years of age.
The story has refocused attention on the importance of vaccination to avert vaccine-preventable disease (VPD) outbreaks. The likelihood of a VPD thriving is greater in locations with a large number of unprotected people. It’s based on this principle that states require children to be vaccinated before entering school systems. And, although other gathering places do not require immunizations, tourist attractions, like amusement parks, that draw large groups of visitors from around the world, are prime locations for outbreaks to originate.
The decision not to vaccinate, or even to delay vaccination, does not occur in a vacuum, nor is it inconsequential. Last year, California parents claimed a record number of personal belief exemptions to mandatory school vaccinations. That was the same year that state health officials reported the most measles cases since 1995 and the most whooping cough cases since 1947. Indeed, more than 80 percent of those infected in the current outbreak are from California. Of interest, on Feb. 5, 2015, two California state legislators have stated they will submit a bill asking for the elimination of California’s personal belief exemption to vaccines.
Impacts of VPD outbreaks
Although this particular outbreak makes for a compelling news story, it’s important to remember that VPD outbreaks don’t have to happen on such a grand scale, or originate at such a well-known location, to have an impact. Any outbreak, anywhere affects not only the infected individuals, but also their families and friends.
For example, a hepatitis A outbreak sickened more than 600 and killed three people in western Pennsylvania in 2003. The people affected by this outbreak had simply gone out to a local restaurant for some Mexican food. Unfortunately, the scallions being served were contaminated with hepatitis A. Nearly 2,000 people had dined at that restaurant during the four days of peak exposure.
Even a small-scale outbreak of a VPD like measles can cause significant and unforeseen inconveniences. In this example from the Parents PACK personal stories collection, a small measles outbreak at a Pennsylvania high school led to unanticipated, and unappreciated, quarantines, when some students had to miss important activities like the prom, graduation and final exams.
As recently as December 2014, an outbreak of mumps affected the National Hockey League infecting 16 players across several teams. Luckily, in most cases, the public did not need to worry about the virus spreading from players on the ice. However, it was around the holidays and these players did likely visit family and friends and travel. One group of unknowingly exposed players even visited a children’s hospital while potentially contagious.
Exposure to a transmissible disease can occur anywhere people gather. It can be at a church gathering, sporting events or even supermarkets — all of which have been documented. As the above examples demonstrate VPDs can occur when you go on vacation, when you go out to eat, or when you go to school. For better or worse, these examples also serve as a reminder that while vaccinations may be a choice, exposures are not.