Patients 1 to 29 from our previous study,²⁴  all infected with HCV genotype 1, were enrolled in a study of viral kinetics and evolution during therapy with pegylated IFNα and ribavirin. Treatment groups A, B, and C are described in “Patients, materials, and methods.” HCV viral load was recorded at frequent intervals during therapy. + and - refer to positive and negative responses, respectively.

A positive day 29 response was defined as a > 2 log₁₀ drop in viral load; a negative day 29 response was defined as a drop of < 1 log₁₀ in viral load.

Early virologic response, EVR, was defined as a > 2 log₁₀ drop in viral load following 12 weeks of therapy.

A positive end-of-treatment response, ETR, was achieved if HCV RNA was undetectable in patient serum at the end of treatment.

An SVR was achieved if HCV RNA remained undetectable in patient serum 6 months after completion of therapy.

These patients, who both achieved SVRs, declined to donate follow-up blood samples at the 72-week time point.

This patient, who was a nonresponder, discontinued therapy before the 48-week point but remained in the study.