FILE - This April 12, 2011 electron microscope image made available by the National Institute of Allergy and Infectious Diseases shows an H9 T cell, blue, infected with the human immunodeficiency virus (HIV), yellow. Research suggests that a shot every one to three months may someday give an alternative to the daily pills that some people take now to cut their risk of getting HIV from sex with an infected partner. An experimental drug given in periodic shots completely protected monkeys from infection in two studies reported at an AIDS conference on Tuesday, March 4, 2014. (AP Photo/NIAID)AP
