A student gets vaccinated against pertussis at a Los Angeles middle school in 2012. The state required that students be immunized to halt an epidemic of whooping cough.
Kevork Djansezian/Getty Images
September 30, 2013 The whooping cough vaccine isn't perfect, but public health officials suspected that something else contributed to the 2010 pertussis outbreak in California. A study finds that neighborhoods where more parents filed for vaccination exemptions for their children had higher rates of infection.
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