[1,6].
In our study, 45% of the patients were aged 70 years or older with a median age of 68.5 years which represents the main risk factor in our population. Only one patient had a medical history of malignancy (colorectal neoplasia).
Thus, we should not sidestep that VZV can affect both immunocompromised as well as immunocompetent persons, even though it is much more likely in the latter group and in the elderly, as was the case with our patients.
Furthermore, previous studies ascertained that increased psychological stress can trigger VZV reactivation. From the beginning of the pandemic, the increasing disease vulnerability, mortality rates, restrictions, and regulations applied to restrain the spread of SARS-CoV-2 infection have been a continued source of stress. COVID-19 vaccines could also be a stress factor, with all the discussions and controversies it has generated [4].
COVID-19 also could be a risk factor as it drops down cell-mediated immunity by inducing lymphopenia and lowering CD3+, CD4+, and CD8+ T cells [4].
In fact, Xu et al. reported that patients contaminated with SARS-CoV-2 have been reported to develop VZV reactivation naturally[7]. The potential mechanism of SARS-CoV-2-associated VZV reactivation could be a cytokine bombardment implicating the release of proinflammatory cytokines, such as interleukin-6, tumor necrosis factor-alpha, and interleukin-12 which affects CD4+ T cells function leads to excessive activation, and potential ensuing exhaustion of CD8+ T cells. [8]
Reviewing the literature, Iwanaga et al. found that VZV reactivation following COVID-19 vaccination was more reported with mRNA vaccines than with other vaccine types. The risk was higher after the first dose than after the second dose with a median age of 58.9 years and a mean duration of 6.75 days [5]. Our results were similar to these findings. In fact, 75% of our patients have received an mRNA vaccine with 50% showing symptomatology after the second dose. The mean duration of symptoms onset was 4.5 days and our patient’s median age was 68.5 years. This association between mRNA vaccines and VZV reactivation could be explained by the main use of mRNA vaccines comparatively to other vaccine types.
We reported only one patient, 80 years old who presented shingle after receiving his first dose of an inactivated vaccine. To our knowledge, VZV reactivation following inactivated COVID-19 vaccine has only been reported in turkey (four cases) and India (one case). Patients’ ages ranged between 21 and 94 years with a mean of 58.9 years. The reactivation seems more common after the first dose of inactivated vaccine than the second dose [5,9].
Herpes zoster Oticus or Ramsay Hunt syndrome (RHS), is a late complication of VZV infection generating inflammation of the geniculate ganglion of cranial nerve VII. RHS is clinically diagnosed typically it’s a triad of otalgia, ipsilateral facial paralysis, and limited skin rash with vesicles near the ear and auditory canal, as was the case for our patient. A rise in the incidence of long-term complications could be attributed to often missed or delayed diagnose [10].
Both VZV reactivation and facial paralysis were reported with virus vaccinations like hepatitis B and influenza vaccines [11].Hence, it’s not astonishing that cases of both conditions be reported in relation to COVID-19 vaccination while the mechanism is still obscure.
After COVID-19 vaccine marketing, there were reported cases of facial paralysis following vaccination, with some cases attributed to the reactivation of VZV [12,13]. The occurrence of the episodes immediately after the vaccine dose in many cases points to the role of the vaccine, even if a causality assessment cannot be proved. For our patient, the onset delay of RHS was three days after the first dose with a recurrence of the symptomatology one week after the second dose, which strongly suggests the role of the mRNA vaccine.
Herein, we would like to draw attention to an important assertion. In fact, while the diagnosis of RHS is clinical it may manifest without skin lesions [14], leading to differential diagnosis problems with unilateral facial paralysis. Thus, without PCR or antibody detection, we could suggest that VZV reactivation induced by the vaccine may be the potential etiology behind this condition.