Peginterferon alfa-2a is a medication used for the treatment of chronic hepatitis B and C infections. It works by stimulating the immune system to fight the virus and slow down or prevent the replication of the virus in the liver. Peginterferon alfa-2a is administered by injection and is generally given for several months.

It might be used alone or in combination with other medications, depending on the type and severity of the infection. Some common side effects of peginterferon alfa-2a include flu-like symptoms like fever, headache, fatigue, and muscle aches.

It might also cause depression, irritability, and other psychiatric side effects, so close monitoring by a healthcare provider is necessary during treatment.