Kelly Koshuta, a basketball star at James Madison High School, Vienna, Va., had surgery to repair an anterior cruciate ligament injured in 2012. Sarah L. Voisin/The Washington Post hide caption

itoggle caption Sarah L. Voisin/The Washington Post

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 hide caption

itoggle caption Noel Celis/AFP/Getty Images

By ensuring vaccines are invented and distributed, Bill Gates says, his foundation is dramatically reducing the number of childhood deaths in poor countries. Marie McGrory/NPR hide caption

itoggle caption Marie McGrory/NPR

A child receives a polio vaccine Sunday in Kano, Nigeria. The country is the primary source of the virus in Africa but appears to be making progress against the disease; the current outbreak in Cameroon that has spread to Equatorial Guinea came by way of Chad, not Nigeria. Sunday Alamba/AP hide caption

itoggle caption Sunday Alamba/AP