Improving preschool immunization levels proving more complex than simply providing vaccines.
Marwick
C
C
D002675:Child, Preschool; D006291:Health Policy; D006801:Humans; D007114:Immunization; D007223:Infant; D014481:United States; D014612:Vaccines / Q000191:economics / Q000600:supply & distribution
D014612:Vaccines