One of the most common childhood illnesses, rotavirus, which infects almost 100 percent of children at one time or another, has been badly beaten down, thanks to the work of a host of researchers from the public and private sectors (including Dr. Paul Offit, a member of the ACSH board of directors, and chief of the division of infectious diseases and director of the Vaccine Education Center at Children s Hospital of Philadelphia), as well as three pharmaceutical companies: Wyeth, Merck and GlaxoSmithKline.