[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.