A new effort is underway to make sure all children who receive government assistance are immunized against childhood diseases. President Clinton has issued an executive memorandum calling for a study of the situation. Vic Tomlinson of the Missouri Department of Health says health officials in this state are already trying to make sure all kids are immunized, but they’ll start doing even more. Tomlinson says the biggest problem areas in Missouri are the state’s urban centers — St. Louis, Kansas City, and Springfield.