The Impact of the COVID-19 Pandemic on the Incidence of Herpes Zoster: A Narrative Literature Review

Abstract

Coronavirus disease 2019 (COVID-19) has had a broad impact on health services and health outcomes. During the pandemic, there were numerous reports of herpes zoster (HZ) in people with COVID-19 and in COVID-19 vaccine recipients. The aim of this review is to elucidate the global effects of the COVID-19 pandemic on HZ. It is postulated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection produces an immunosuppressive state that favours varicella zoster virus (VZV) reactivation. Three large cohort studies (a multinational study and studies from the USA and Spain) that excluded individuals vaccinated against HZ reported significantly increased risk of HZ following COVID-19 infection, especially in people aged ≥ 50 years. In contrast, a large study from Israel that did not consider HZ vaccination status reported no such increase. Cases of HZ following COVID-19 vaccination have been reported and may be the result of attenuated cell-mediated immunity. This phenomenon appears to vary by vaccine type. Some (but not all) large analyses have reported a significant positive relationship between receipt of mRNA vaccines for COVID-19 and development of HZ. These include analyses of health records databases in Israel and Hong Kong and of spontaneous case reports in the US Vaccine Adverse Event Reporting System (VAERS) database. Routine vaccinations, including shingles vaccine programmes, were disrupted by the COVID-19 pandemic. It is estimated that missed shingles vaccinations may have resulted in 63,117 avoidable HZ cases in the USA. Now that the World Health Organization has declared an end to the COVID-19 pandemic as a health emergency and routine vaccination services have resumed, there is a need to increase awareness of HZ and HZ vaccination.Graphical abstract available for this article.

Keywords: COVID-19; Herpes zoster; Incidence; SARS-CoV-2; Vaccination; Vaccine-preventable disease; Varicella zoster virus; mRNA vaccine.

Fig. 1

Retrospective studies that have investigated associations between HZ following COVID-19. ^aRisk reported as hazard ratio; ^brisk reported as adjusted incidence rate ratio; ^crisk reported as adjusted relative risk; and ^drisk reported as risk ratio. CI confidence interval, COVID-19 coronavirus disease 2019, HZ herpes zoster, yrs years

Fig. 2

Retrospective studies that have investigated associations between HZ following COVID-19 vaccination. CI confidence interval, COVID-19 coronavirus disease 2019, HZ herpes zoster, RR relative risk