Objective: To assess whether varicella zoster virus (VZV) DNA can be detected in blood before herpes zoster (HZ) rash onset. Method: Monocentric retrospective study from January 2019 to March 2023 including patients with HZ and stored blood samples performed during the week preceding the onset of HZ rash. Blood samples were retrospectively analyzed for VZV DNA by quantitative PCR. Results: Among the 138 patients with HZ during the study period, stored blood samples performed during the week preceding the onset of HZ rash were available for 13 of them. Twelve (92%) patients were immunosuppressed, mostly due to solid organ transplantation (38%), solid malignancy (31%) or autoimmune disease (23%). During the week preceding HZ onset, VZV DNA was detected in blood from 10 (77%) patients, with a median value of 3.6 log (copies/mL) (IQR 3.3-3.9). At the time of HZ onset, all VZV PCR performed in available blood samples were positive. Conclusion: Our findings demonstrates that VZV DNA can be commonly detected in blood from immunocompromised patients during the prodromal phase of HZ. Early screening of VZV DNA in blood from high-risk immunocompromised patients might improve HZ therapeutic management.