A study came out in Pediatrics last week that looked at how vaccine exemptions were related to a statewide outbreak of pertussis (also known as whooping cough) in California in 2010. As you might expect, the authors found that there were more whooping cough cases in areas with higher rates of vaccine exemptions. 

These findings were true even when the authors controlled for certain demographic factors like race/ethnicity, population density, family size, education level, and household income. Findings of this study underscore the need for everyone to be vaccinated in order to prevent personal risk of getting vaccine-preventable diseases, and to prevent passing these diseases along to those who are too young or not able to be vaccinated.