Increased Risk of Herpes Zoster in Adults ≥50 Years Old Diagnosed With COVID-19 in the United States.

Background: Case reports have described herpes zoster (HZ) in patients with coronavirus disease 2019 (COVID-19). However, this constitutes low-quality evidence for an association. We therefore performed a retrospective cohort study to assess the risk of developing HZ following a COVID-19 diagnosis. Methods: We compared the HZ incidence in ≥50-year-olds diagnosed with COVID-19 vs those never diagnosed with COVID-19. We used data from the US MarketScan Commercial Claims and Encounters and Medicare Supplemental (3/2020-2/2021) and Optum Clinformatics Data Mart (3-12/2020) databases. Individuals with COVID-19 were exact-matched 1:4 to those without COVID-19 by age, sex, presence of HZ risk factors, and health care cost level. Adjusted incidence rate ratios (aIRRs) were estimated by Poisson regression. Results: A total of 394 677 individuals ≥50 years old with COVID-19 were matched with 1 577 346 individuals without COVID-19. Mean follow-up time after COVID-19 diagnosis and baseline characteristics were balanced between cohorts. Individuals diagnosed with COVID-19 had a 15% higher HZ risk than those without COVID-19 (aIRR, 1.15; 95% CI, 1.07-1.24; P < .001). The increased HZ risk was more pronounced (21%) following COVID-19 hospitalization (aIRR, 1.21; 95% CI, 1.03-1.41; P = .02). Conclusions: We found that COVID-19 diagnosis in ≥50-year-olds was associated with a significantly increased risk of developing HZ, highlighting the relevance of maintaining HZ vaccination.

Recombinant Adjuvanted Zoster Vaccine and Reduced Risk of Coronavirus Disease 2019 Diagnosis and Hospitalization in Older Adults.

BACKGROUND: Some vaccines elicit nonspecific immune responses that may protect against heterologous infections. We evaluated the association between recombinant adjuvanted zoster vaccine (RZV) and coronavirus disease 2019 (COVID-19) outcomes at Kaiser Permanente Southern California. METHODS: In a cohort design, adults aged ≥50 years who received ≥1 RZV dose before 1 March 2020 were matched 1:2 to unvaccinated individuals and followed until 31 December 2020. Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for COVID-19 outcomes were estimated using Cox proportional hazards regression. In a test-negative design, cases had a positive severe acute respiratory syndrome coronavirus 2 test and controls had only negative tests, during 1 March-31 December 2020. Adjusted odds ratios (aORs) and 95% CIs for RZV receipt were estimated using logistic regression. RESULTS: In the cohort design, 149 244 RZV recipients were matched to 298 488 unvaccinated individuals. The aHRs for COVID-19 diagnosis and hospitalization were 0.84 (95% CI, .81-.87) and 0.68 (95% CI, .64-.74), respectively. In the test-negative design, 8.4% of 75 726 test-positive cases and 13.1% of 340 898 test-negative controls had received ≥1 RZV dose (aOR, 0.84 [95% CI, .81-.86]). CONCLUSIONS: RZV vaccination was associated with a 16% lower risk of COVID-19 diagnosis and 32% lower risk of hospitalization. Further study of vaccine-induced nonspecific immunity for potential attenuation of future pandemics is warranted.

Can COVID-19 Increase the Risk of Herpes Zoster? A Narrative Review.

Herpes zoster (HZ) is associated with substantial morbidity. It is caused by reactivation of the latent varicella zoster virus (VZV) following decline in cell-mediated immunity, which is commonly age-related, but also occurs in individuals with immunosuppressive diseases and/or treatment. Since coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, has been associated with T cell immune dysfunction and there have been reports of HZ in COVID-19 patients, we have performed a review of available literature on whether COVID-19 could trigger HZ. We identified 27 cases of HZ following COVID-19, which most frequently occurred within 1-2 weeks of COVID-19, and the majority of cases had typical presentation. Atypical presentations of HZ were noted especially in patients with lymphopenia. It has been hypothesized that VZV reactivation occurs as a consequence of T cell dysfunction (including lymphopenia and lymphocyte exhaustion) in COVID-19 patients. Based on current evidence, which is limited to case reports and case series, it is not possible to determine whether COVID-19 increases the risk of HZ. Practitioners should be aware of the possible increased risk of HZ during the pandemic period and consider timely therapeutic and preventive measures against it.