A woman receives a dose of a newly developed Ebola vaccine at the NIH Clinical Center in Bethesda, Md., last week, in a photo from the National Institute of Allergy and Infectious Diseases.
Marqui Ducarme is aided by his wife after catching chikungunya at his home in Port-au-Prince, May 23. The virus swept through Haiti this spring, infecting more than 40,000 people.
A doctor gives a polio vaccine to a child at a health clinic in Baghdad last week. The CIA says it banned the use of vaccine programs as cover for spying last year — a practice health officials said had wide repercussions.
Ahmad Al-Rubaye/AFP/Getty Images
There today, here tomorrow: A mother holds her child for a measles vaccination in Manila, Philippines, in January. Travelers are bringing measles from the Philippines to the United States.
Noel Celis/AFP/Getty Images