mRNA COVID-19 Vaccines Show No Link to Varicella Zoster Virus Reactivation

The relationship between mRNA COVID-19 vaccination and varicella zoster virus vaccination are assessed.

Receipt of an mRNA COVID-19 vaccine is not associated with reactivation of the varicella zoster virus, according to study findings published in the Journal of the American Academy of Dermatology.

The retrospective cohort study relied on a federated health research network that included aggregated health record data from 63 health care organizations comprising approximately 70 million patients. The researchers focused their analysis of patients 18 years of age or older who received a first or second dose of an mRNA COVID-19 vaccine from December 2020 to July 2021.

The main outcome of the analysis – herpes zoster reactivation related to mRNA COVID-19 vaccination – was defined as the occurrence of herpes zoster reactivation within 28 days of vaccination.

Researchers established a cohort population of patients with acne, dry skin, viral wart, melanocytic nevi, lipoma, seborrheic keratosis, and skin cysts, all of whom had no COVID-19 vaccination history documented in the database. Control participants were divided into 2 cohorts: a historical control group of patients who received their diagnoses from January 2020 to December 2020; and a contemporary cohort who received their diagnosis from December 2020 to July 2021.

A total of 1,306,434 individuals (mean age, 55.1 years; 57% women) in the research network had received a dose of an mRNA COVID-19 vaccine. Approximately 65% of these recipients were White, 14% were Black, 11% were Hispanic or Latino, and 6% were Asian.

There was no difference between patients who received the mRNA COVID-19 vaccine vs the historical cohort in terms of varicella zoster virus reactivation within 28 days of vaccination (relative risk [RR], 0.91; 95% CI, 0.81-1.01). In addition, there was no difference between the mRNA COVID-19 vaccination cohort and the contemporary cohort that did not receive an mRNA vaccine in terms of virus reactivation within 28 days (RR, 0.98; 95% CI, 0.87-1.11).

The researchers noted that the analysis was limited by possible misclassification bias, which is reportedly inherent in the use of diagnostic codes. Also, the researchers suggest that some patients may have developed herpes zoster after vaccination but did not seek care, which may further limit the findings.

Given that fears of potential adverse effects from vaccination can ultimately “drive vaccine refusal and subsequent preventable disease and death,” the investigators wrote they hope the findings provide “reassurances to patients and to the providers caring for them.”


Birabaharan M, Kaelber DC, Karris MY. Risk of herpes zoster reactivation after messenger RNA COVID-19 vaccination: A cohort study. J Am Acad Dermatol. Published online November 23, 2021. doi:10.1016/j.jaad.2021.11.025