Guillain Barre Syndrome (GBS) 89 days after the 3rd shot (First Monovalent Booster); This spontaneous case was reported by a patient and describes the occurrence of GUILLAIN-BARRE SYNDROME (Guillain Barre Syndrome (GBS) 89 days after the 3rd shot (First Monovalent Booster)) in a 55-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 939909, 003C21A and 038B21A) for COVID-19 vaccination.     No Medical History information was reported.   On 08-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 05-May-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 22-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 19-Feb-2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced GUILLAIN-BARRE SYNDROME (Guillain Barre Syndrome (GBS) 89 days after the 3rd shot (First Monovalent Booster)) (seriousness criteria hospitalization and medically significant). The patient was hospitalized from sometime in February 2022 to sometime in July 2022 due to GUILLAIN-BARRE SYNDROME. At the time of the report, GUILLAIN-BARRE SYNDROME (Guillain Barre Syndrome (GBS) 89 days after the 3rd shot (First Monovalent Booster)) outcome was unknown.            No concomitant medications was reported. After the first primary and second shot patient did not had any side effects. It was reported that right away after the 3rd shot (first booster) patient did not had any side effects but after 89 days of the 3rd shot he developed Guillain Barre Syndrome (GBS) and stated that he did not had any other shot in that time period. He was in hospital for 5 months (Feb-2022 to Jul-2022).  Patient was taking medications but did not feel like sharing the medication names.  Company Comment: This spontaneous case concerns a 55 year old male with no medical history reported , who experienced the Serious (Hospitalization, Medically significant) , unexpected , event of Guillain Barre Syndrome about 89 days after receiving  the 3 dose of mRNA1273 vaccine, in the covid 19 vaccination series. Patient received the 1 and 2 doses of Moderna vaccines about 6 and 5 months respectively, prior to receiving the Booster dose, with no adverse events reported for the primary doses. It was reported that right after the 3rd shot (first booster) patient did not had any side effects but after 89 days of the 3rd shot he developed Guillain Barre Syndrome (GBS) and stated that he did not had any other shot in that time period. He was in hospital for 5 months. Details on symptoms, clinical course,  labs, diagnostic procedures, concomitant and Treatment medications were not provided.  The event outcome is reported as unknown. The benefit -risk relationship of mRNA -1273 ( Moderna Covid 19 Vaccine) is not affected by this report.; Sender's Comments: Company Comment: This spontaneous case concerns a 55 year old male with no medical history reported , who experienced the Serious (Hospitalization, Medically significant) , unexpected , event of Guillain Barre Syndrome about 89 days after receiving  the 3 dose of mRNA1273 vaccine, in the covid 19 vaccination series. Patient received the 1 and 2 doses of Moderna vaccines about 6 and 5 months respectively, prior to receiving the Booster dose, with no adverse events reported for the primary doses. It was reported that right after the 3rd shot (first booster) patient did not had any side effects but after 89 days of the 3rd shot he developed Guillain Barre Syndrome (GBS) and stated that he did not had any other shot in that time period. He was in hospital for 5 months. Details on symptoms, clinical course,  labs, diagnostic procedures, concomitant and Treatment medications were not provided.  The event outcome is reported as unknown. The benefit -risk relationship of mRNA -1273 ( Moderna Covid 19 Vaccine) is not affected by this report.