Can SARS‐CoV‐2 vaccine increase the risk of reactivation of Varicella zoster? A systematic review

INTRODUCTION: Although the COVID‐19 vaccination is deemed safe, exact incidence and nature if adverse effects, particularly dermatological ones, are still unknown. OBJECTIVE: To describe the demographic, clinical, morphological characteristics, outcomes, and timing of development of herpes zoster to the various COVID‐19 vaccines. And to identify on whether COVID‐19 vaccine has temporal relationship between development of herpes zoster (HZ). METHODS: We have performed a systemic review of articles from PubMed and Embase using MeSH and keywords like “Shingles,” “Herpes zoster,” “Varicella zoster,” “COVID‐19,” “Vaccine,” “SARS‐CoV‐2.” No filters including country of publication, language, type of articles were applied. Individual case report references were filtered for any pertinent cases. RESULTS: A total of 54 cases consisting of 27 male and 27 female patients have been reported. There were cases with known risk factors for herpes zoster, which included age more than 50 years (n = 36), immunological disorders (n = 10), chronic disease (n = 25), metabolic disorder (n = 13), malignancy (n = 4), and psychiatric disorder (n = 2). The mean (SD) period between development of herpes zoster and COVID‐19 vaccination was 7.64 (6.92) days. Majority of the cases were from the high‐income and/or middle‐income countries. 86.27% of the cases of HZ were reported due to mRNA vaccine. Thirty‐six patients 36/45 (80%) developed herpes zoster following the priming dose of COVID‐19 vaccine among those who received mRNA vaccine. CONCLUSION: We could not establish definite link but there may be possible association between COVID‐19 vaccine and shingles. Large‐scale studies may help to understand the cause‐effect relationship.