Long‐term risk of herpes zoster following COVID‐19: A retrospective cohort study of 2 442 686 patients

Abstract The long‐term risk of herpes zoster (HZ) after recovery from a SARS‐CoV‐2 infection is unclear. This retrospective cohort study assessed the risk of HZ in patients following a COVID‐19 diagnosis. This retrospective, propensity score‐matched cohort study was based on the multi‐institutional research network TriNetX. The risk of incident HZ in patients with COVID‐19 was compared with that of those not infected with SARS‐CoV‐2 during a 1‐year follow‐up period. Hazard ratios (HRs) and 95% confidence intervals (CIs) of HZ and its subtypes were calculated. This study identified 1 221 343 patients with and without COVID‐19 diagnoses with matched baseline characteristics. During the 1‐year follow‐up period, patients with COVID‐19 had a higher risk of HZ compared with those without COVID‐19 (HR: 1.59; 95% CI: 1.49–1.69). In addition, compared with the control group patients, those with COVID‐19 had a higher risk of HZ ophthalmicus (HR: 1.31; 95% CI: 1.01–1.71), disseminated zoster (HR: 2.80; 95% CI: 1.37–5.74), zoster with other complications (HR: 1.46; 95% CI: 1.18–1.79), and zoster without complications (HR: 1.66; 95% CI: 1.55–1.77). Kaplan–Meier curve analysis (log‐rank p < 0.05) results indicated that the risk of HZ remained significantly higher in patients with COVID‐19 compared with those without COVID‐19. Finally, the higher risk of HZ in the COVID‐19 cohort compared with that in the non‐COVID‐19 cohort remained consistent across subgroup analyses regardless of vaccine status, age, or sex. The risk of HZ within a 12‐month follow‐up period was significantly higher in patients who had recovered from COVID‐19 compared with that in the control group. This result highlights the importance of carefully monitoring HZ in this population and suggests the potential benefit of the HZ vaccine for patients with COVID‐19.