What is the definition or description of: pegasys allergy?

Pegasys allergy: Pegasys (Peginterferon alfa-2a) is an immunosuppressive & antiviral medication used in the treatment of hepatitis B or C. An allergy occurs when your body’s immune system creates antibodies to a foreign substance causing a reaction that can be mild to severe. For potential adverse effects see: https://www.drugs.com/pegasys.html