see more

WASHINGTON, DC - NOVEMBER 19: Thomas Frieden, Director of the Centers for Disease Control and Prevention, testifies during a Senate Homeland Security and Governmental Affairs Committee hearing November 19, 2014 in Washington, DC. The committee heard testimony on the topic of "Preparedness and Response to Public Health Threats: How Ready Are We?" (Photo by Win McNamee/Getty Images)

WASHINGTON, DC - NOVEMBER 19:  Thomas Frieden, Director of the Centers for Disease Control and Prevention, testifies during a Senate Homeland Security and Governmental Affairs Committee hearing November 19, 2014 in Washington, DC. The committee heard testimony on the topic of "Preparedness and Response to Public Health Threats: How Ready Are We?"  (Photo by Win McNamee/Getty Images)