Before considering vaccine information on the Internet, confirm that the information comes from a credible source and is updated on a regular basis. CDC’s vaccines and immunization web content is researched, written and approved by subject matter experts, including physicians, researchers, epidemiologists, and analysts. Content is based on peer-reviewed science. CDC leadership makes the final decision on the words, images and links to best serve the information needs of the public as well as healthcare providers, public health professionals, partners, educators, and researchers. Science and public health data are frequently updated. Most pages are reviewed yearly.