LAUSR

We hereby report two cases of GBS occurred within a population of 76,640 people who received either the first or second dose of one of the approved Covid-19 vaccines as of April 15th, 2021, in Udine province, Italy (current resident population 516,418 inhabitants). The first patient was a 90-year-old man, previously in good physical and mental conditions, who developed acute progressive gait imbalance three days after receiving the second dose of BNT162b2 vaccine. Electroneuromyography (ENMG) performed at three weeks from the onset of symptoms, showed signs of acute four limbs axonal sensory-motor polyneuropathy, while cerebrospinal fluid (CSF) analysis was normal. Acute motor sensory axonal neuropathy (AMSAN) was diagnosed according to the current electrophysiological criteria [1], the patient was admitted for clinical monitoring and intravenous immunoglobulins (ivIG) were administered. Serum autoimmunity revealed high titer anti-GQ1b and anti-titin antibodies. Considering anti-titin positivity, ENMG was repeated, excluding neuromuscular junction involvement and completion with thoracic computer tomography scan excluded thymoma. During his hospital stay, he remained clinically stable and was discharged home able to stand and walk with minor assistance. The second patient was a 51-year-old woman who developed distal limb paresthesias with new-onset sphincter disturbances and lumbar pain, ten days after receiving the first dose of ChAdOx1 nCoV-19 vaccine. ENMG examination showed F-wave conduction delay while CSF presented marked albumin-cytological dissociation. Acute inflammatory demyelinating polyneuropathy (AIDP) was diagnosed, the patient was admitted for clinical monitoring and ivIG were administered. During her hospital stay she developed facial diplegia, bilateral foot dorsiflexion weakness (MRC 4/5) and lower limbs areflexia. A whole spine magnetic resonance imaging was unremarkable. Serum autoimmunity, including search for anti-ganglioside antibodies, was negative. Distal limb neuropathic pain required introduction of analgesic therapy. The patient was discharged home able to walk unaided. Patients’ details are available in Table 1. GBS is described as a complication following different kinds of vaccinations, and the Brighton Collaboration GBS Working Group has developed guidelines which are intended to help in reporting cases of GBS as adverse events following immunization and to harmonize vaccine safety reporting: in fact, GBS can be temporally associated with, but is not necessarily the result of the vaccine [2]. As regards Covid19 immunization, a recent report from the Janssen Ad26. COV2.S vaccine trial has highlighted that GBS may occur in the context of the vaccination as well as in the placebo arm with the same incidence, supporting a casual role [3]. Concerning BNT162b2 and ChAdOx1 nCoV-19 vaccines instead, one case of GBS following the administration of each vaccine has been reported so far [4, 5]. Moreover, amid the global vaccination program, it is expected that many GBS cases would be identified by chance in the 10 weeks period following a double dose vaccination and that this association cannot be considered a causal link [6]. GBS has also been extensively reported after Covid-19 infection: AIDP is the most common form, but acute motor * Francesco Bax [email protected]