Vikram is the first child to wear a Khushi Baby necklace, which will keep track of his immunizations. He's at a vaccine clinic in Rajasthan, India. Ruchit Nagar/Courtesy of Khushi Baby hide caption

itoggle caption Ruchit Nagar/Courtesy of Khushi Baby

Proteins and enzymes that will produce antibodies for the experimental Ebola drug ZMapp are developed on the leaves of the nicotiana benthamiana plant, a relative of tobacco. Here, indicator proteins glow under ultraviolet light — a way to assess the success of bacteria spread. Sean Gallup/Getty Images hide caption

itoggle caption Sean Gallup/Getty Images

A health worker administers the malaria vaccine at a clinical trial in Kilifi, Kenya. Joseph Okanga/Reuters /Landov hide caption

itoggle caption Joseph Okanga/Reuters /Landov

Kimberly Delp gives a flu shot to Carleen Matthews at the Homewood Senior Center in Pittsburgh, Pa., last September. Andrew Rush/AP hide caption

itoggle caption Andrew Rush/AP