Expert answer: The BabyCenter Editorial Team

Your first instinct may be to wait until your baby is completely well, but actually it's fine for him or her to be immunized during a mild illness like a cold or an earache.

If your child has a fever over 101 degrees Fahrenheit or a serious infection like pneumonia or the flu, however, the doctor will probably suggest waiting. That's so your baby won't have to deal with routine side effects from the shot on top of symptoms from his or her illness – not because the vaccine will be less effective if your child is sick. 

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