[6] They may include headache, feeling tired, depression, trouble sleeping, hair loss, nausea, pain at the site of injection, and fever.

[3] Severe side effects may include psychosis, autoimmune disorders, blood clots, or infections.

[7] This drug is approved around the world for the treatment of chronic hepatitis C (including people with HIV co-infection, cirrhosis, 'normal' levels of ALT) and has recently been approved (in the EU, U.S., China and many other countries) for the treatment of chronic hepatitis B.

This finding, originally reported in Nature,[9] showed genotype 1 hepatitis C patients carrying certain genetic variant alleles near the IL28B gene are more likely to achieve sustained virological response after the treatment than others.

[12][13][14][15][16] In May 2022, Roche Australia transferred the sales and marketing of Pegasys to Echo Therapeutics Pty Ltd.[17] A Cochrane Review sought to determine whether interferon alfa-2a could be used as a treatment for individuals with neovascular age-related macular degeneration.