A Study of Combination Treatment With Peginterferon Alfa-2a (Pegasys) Plus Ribavirin (Copegus) in Participants With Chronic Hepatitis C

Inclusion Criteria: * Adult participants at least 18 years of age * Chronic hepatitis C, with detectable serum hepatitis C virus (HCV) ribonucleic acid (RNA) * Scheduled for treatment with peginterferon alfa-2a * Compensated liver disease * Women in fertile age must be informed about obligation of using adequate contraception during and 6 months post treatment with ribavirin (Copegus®) * Men with a sexual partner in fertile age must be informed about obligatory contraception preventing pregnancy during the course of treatment with ribavirin (Copegus®) as well as 6 months after treatment cessation * Female participants in the study must have a negative pregnancy test performed not sooner than within 2 weeks preceding the planned inclusion to the study * Men with a sexual partner in fertile age must produce a negative result of the partner's pregnancy test performed not sooner than within 2 weeks preceding the planned partner's inclusion to the study Exclusion Criteria: * Chronic liver disease other than chronic hepatitis C * Active hepatitis A virus or hepatitis B virus infection * Therapy with any systemic antiviral, antineoplastic or immunomodulatory treatment less than or equal to (\<=) 6 months prior to first dose of study drug * Hemoglobin \<120 grams per liter (g/L) in female participants or \<130 g/L in male participants (the result must not be older than 2 weeks prior to inclusion to the study) * Platelet count \<90 x 10\^9/liter (the result must not be older than 2 weeks prior to inclusion to the study * Neutrofil count \<1.5 x 10\^9/liter (the result must not be older than 2 weeks prior to inclusion to the study) * Participants with increased risk of anaemia, or participants at risk of serious health problems resulting from anaemia or decrease of hemoglobin (e.g., participants with serious cardiovascular or cerebrovascular disease) * History or presence of a serious mental disease, especially depression, which, in the investigator's opinion, does not allow administration of peginterferon alfa-2a (Pegasys®) * History or presence of a disease consequent to immunodeficiency (e.g., inflammatory diseases of intestine, idiopathic thrombocytopenic purpura, systemic lupus erythematosus, rheumatoid arthritis)