We started doing the DPT and OPV at the 4 year checkup several years ago to decrease the number of injections at the 5 yr. checkup when our state shifted to MMR at age 5. We also were trying to spread out the expense. Now with managed care paying for most people's imms my associates have switched to giving the MMR at age 4 which is the same thing that our local health dept. does. Does anyone have any data or opinions about whether any of this makes a difference? I had thought that years ago I had read that you get a better anamnestic response by giving the 2nd booster later (like just before middle school) but most states have opted to MMR before KG because of the higher percentage of kids that are seen by health officials at that time.