Background  Peginterferon-α–based therapy frequently leads to neutropenia. It remains unclear whether neutropenia is associated with bacterial infection in chronic hepatitis C (CHC).

Aim  To evaluate the risk of bacterial infection and neutropenia in patients with CHC treated with peginterferon-α/ribavirin.

Methods  In all, 207 patients with CHC with (group A, = 30) and without (group B, = 177) baseline neutropenia were treated with peginterferon-α/ribavirin.

Results  Group A had significantly higher rates of moderate (<750 cells/μL) and severe (<500 cells/μL) neutropenia than group B (70.0% and 26.7% vs. 20.3% and 8.5% respectively, both < 0.0001). The sustained virological response rate was similar between patients with and without neutropenia, at baseline or during treatment. Bacterial infection occurred in 4.3% of patients. Group A and patients with lower baseline neutrophil counts had substantially higher rates of bacterial infection. Patients with cirrhosis had significantly higher rates of infection during combination therapy than those without cirrhosis (15%, 3 of 20 vs. 3.2%, 6 of 187, = 0.045). Nadir neutrophil counts were not correlated to infection episodes.

Conclusions  Bacterial infection during peginterferon-based therapy for CHC was associated with comorbidity of cirrhosis, but not with neutropenia, whether at baseline or during treatment. Neutropenic CHC patients might be treated safely with close monitoring.