A big change in the way your young kids get their vaccines will mean fewer screams in the pediatrician's office. A new vaccine that promises to cut out six of the twenty injections that babies get before the age of two won federal approval this week. The vaccine called Pediarix, combines into one injection today's shots that protect against five diseases. Pediarix won Food And Drug Administration approval after studies involving thousands of babies proved it was effective as the nine separate shots. The combination vaccine will begin selling early next month, and cost about the same as the separate injections added together. It is recommended that the vaccine be given as a 3-dose series to infants at 2, 4 and 6 months of age.