Herpesviruses reactivation following COVID-19 vaccination: a systematic review and meta-analysis

A systematic review and meta-analysis of herpes zoster occurrence/recurrence after COVID-19 infection and vaccination

To inform surveillance, prevention, and management strategies for the varicella zoster virus (VZV) during the COVID-19 pandemic, this study aimed to evaluate the risk of herpes zoster (HZ) occurrence/recurrence following COVID-19 infection and vaccination. A comprehensive search across seven databases was conducted up to January 31, 2024, to identify studies relevant to the occurrence of HZ following COVID-19 infection and vaccination. The meta-analysis included five studies on postinfection HZ and 13 studies on postvaccination HZ. Patients infected with COVID-19 had a 2.16-fold increased risk of HZ (95% confidence interval [CI]: 1.24-3.76) than uninfected individuals. However, there was no significant association between COVID-19 vaccination and the risk of HZ compared to controls, with a relative risk (RR) of 1.08 (95% CI: 0.84-1.39). Furthermore, a descriptive analysis of 74 postinfection and 153 postvaccination HZ studies found no significant differences on gender or age (<50 and ≥50 years) following COVID-19 infection. Notably, 44.0% of the HZ cases postinfection appeared within the first week, with 69.5% resolving within 10 days, predominantly presenting as skin lesions. In the postvaccination group, the majority (60.1%) developed HZ after the first dose and 66.7% occurred within 1 week. Moreover, 44.6% resolved within 10 days and 50.0% within a month, primarily exhibiting skin lesions and postherpetic neuralgia. The study found that COVID-19 infection increases the risk of HZ, but the COVID-19 vaccine does not. Further study is needed to explore the association between COVID-19 and HZ.

Herpes zoster after the third dose of SARS-CoV-2 mRNA-BNT162b2 vaccine in actively treated cancer patients: a prospective study

Several concerns have been raised about a causal relationship between COVID-19 mRNA-based vaccines and the development of herpes zoster (HZ). We performed a prospective analysis of the Vax-On-Third-Profile study to investigate the incidence of HZ after the third dose of mRNA-BNT162b2 (tozinameran) and its correlation with immune responses. Patients who had received a booster dose and had been actively treated for at least 8 weeks were eligible. Serologic assessment was performed before the third dose of tozinameran (timepoint-1) and 4 weeks later (timepoint-2). We also assessed the incidence of SARS-CoV-2 breakthrough infections at predefined time points. The current analysis included 310 patients, of whom 109 (35.2%) and 111 (35.8%) were being treated with targeted therapies and cytotoxic chemotherapy, respectively. All participants received a third dose of tozinameran between September 26 and October 30, 2021. After a mean follow-up of 17.3 (IQR 15.1-18.4) months, HZ occurred in 8 recipients, for a cumulative incidence of 2.6%, and an incidence rate of 0.310 per person-year (95% CI 0.267-0.333). All HZ cases occurred within 30 days of booster dosing (range 5-29 days), with a median time to onset of 15 (IQR 9-22) days. Among the 7 patients (2.2%) who also contracted a SARS-CoV-2 infection, all cases preceded COVID-19 outbreaks. No instances of complicated HZ were reported. In multivariate analysis, impaired T helper and T cytotoxic cell counts independently correlated with HZ occurrence. These findings provide the first evidence that cancer patients on active treatment have a not negligible risk of developing HZ within 30 days after the third dose of tozinameran. The favorable clinical outcome of all observed cases confirms that protective effects of boosters in reducing the risk of severe COVID-19 outweigh the potential risk of HZ occurrence.

Herpes Zoster and COVID-19 Vaccination: A Narrative Review

COVID-19 was a worldwide emergency, leading to a global health crisis, which completely revolutionized every aspect of human life. Several strategies were adopted to limit the spreading of the infection such as testing and contact tracing, quarantine and isolation, use of face mask, social distancing, lockdowns, travel restrictions, etc. Of these, vaccines were the most important measures to reduce the transmission of the virus and the severity of the infection, in order to overcome the pandemic. Fortunately, vaccination campaign was a success, showing to be efficient in controlling and preventing the COVID-19, reducing the risk of disease progression, hospitalization, and mortality. Monitoring and addressing vaccine-related adverse events have been essential for maintaining public confidence. Indeed, with the increasing number of vaccines administered, various cutaneous reactions have been reported, making dermatologists key players in their recognition and treatment. Particularly, several cutaneous diseases and cutaneous findings have been reported. Of note, also viral reactivations have been described following COVID-19 vaccination. Among these, varicella zoster virus (VZV) reactivation has been collected. Globally, an early diagnosis and an accurate treatment of herpes zoster (HZ) is mandatory to reduce possible complications. In this context, we conducted a review of the current literature investigating cases HZ following COVID-19 vaccination with the aim of understanding the possible causal correlation and underlying pathogenetic mechanisms to offer clinicians a wide perspective on VZV reactivation and COVID-19 vaccines.