Infants may or may not have a reaction to polio vaccine that manifests itself in obvious symptoms.
After polio vaccination, infants may experience some degree of adverse reactions. Common symptoms such as fever, skin rash, and hard nodules are normal adverse reactions due to allergy to some of the vaccine components and are self-limiting, usually resolving within 1 week or so.
However, there may be no symptoms, which means that the infant is not allergic to the components of the vaccine. This does not affect the effectiveness of the vaccine, and an adverse reaction is not a sign that the vaccine is working. If the reaction is severe, it is necessary to consult a doctor for treatment.