Herpes Zoster Risk Among US Cancer Patients Following Initiation of Immunosuppressive Therapy.

Purpose: Cancer and immunosuppressive medications used for its treatment increase the risk for herpes zoster (HZ) among adults. This study described the incidence of HZ and its complications among United States (US) adults with specific solid tumors and hematological malignancies following initiation of immunosuppressive therapy.

Patients and methods: This retrospective cohort study used administrative claims data from October 2015 to December 2022 and included US adults with ≥1 immunosuppressive medication claim, ≥12 months continuous enrollment (baseline) prior to the first immunosuppressive medication claim, a cancer diagnosis, and no HZ diagnosis or vaccination in the baseline period. HZ incidence rates (IRs) were calculated as the number of new HZ cases per 1000 person-years at risk, stratified by cancer type and medication class. The proportions of patients with HZ-related complications such as postherpetic neuralgia, herpes zoster ophthalmicus, disseminated HZ, and HZ-related meningoencephalitis were described. A time-dependent Cox proportional hazards regression estimated adjusted hazard ratios, controlling for patient age, sex, race and ethnicity, comorbidities, prior healthcare utilization, insurance type, region, and baseline immunosuppressive medication use.

Results: The overall IRs of new HZ cases in patients with a solid tumor or a hematological malignancy were 20.9 (95% confidence interval [CI]: 20.33‒21.52) and 31.1 (95% CI: 29.64‒32.52) per 1,000 person-years, respectively. HZ IR was highest in patients with non-Hodgkin lymphoma (35.4, 95% CI: 33.05‒37.77) or chronic lymphocytic leukemia (35.1, 95% CI: 31.24‒39.24). By medication class, the highest HZ IRs were associated with mycophenolic acid, azathioprine, and oral glucocorticoids. In adjusted analyses, patients were more likely to develop HZ during periods of immunosuppressive medication use versus periods without (adjusted hazards ratio [95% CI]: 3.2 [3.01‒3.39] for solid tumor, 3.2 [2.89‒3.57] for hematological malignancy).

Conclusion: HZ incidence among US adults with solid tumors and hematological malignancies following immunosuppressive therapy initiation was high, reinforcing the need to prioritize HZ vaccination in these populations.