blood in poop; patient had a problem with his lungs; bumps on eyes; very sick; weak joints and muscles; mouth is enlarged with the right side being swollen; speech was a bit slurred due to trouble talking; due to swollen mouth barely talk and it hurts for him to talk / pain; coughing; Initial information was received on 28-Sep-2020 regarding an unsolicited valid serious case from a patient (other non-professional) in the United States.  This case involves a male patient (age unspecified) who had problems with his lungs (lung disorder), became very sick (malaise), mouth is enlarged with the right side being swollen (mouth swelling), speech was a bit slurred due to trouble talking (dysarthria), due to swollen mouth barely talk and it hurts for him to talk / pain (oral pain), had bumps on his eyes (eye disorder) and developed weak joints and muscles (muscular weakness), coughing (cough) and blood in poop (haematochezia), while he received INFLUENZA QUADRIVAL A-B MULTIDOSE VACCINE PRESERVED [FLUZONE].  Medical history, medical treatment, vaccination and family history were not provided. It was reported that, patient did not receive any other vaccine concomitantly.  On 23-Sep-2020, the patient received a 0.5 mL dose of suspect INFLUENZA QUADRIVAL A-B MULTIDOSE VACCINE PRESERVED [lot number and expiry date not reported] via an intramuscular route at an unknown administration site for prophylactic vaccination.  On an unknown date, the patient had problems with his lungs (lung disorder), (unknown latency) following the administration of INFLUENZA QUADRIVAL A-B MULTIDOSE VACCINE PRESERVED. It was reported that the patient had terrible first night due to this. On an unknown date, the patient became became very sick (malaise), mouth is enlarged with the right side being swollen (mouth swelling), speech was a bit slurred due to trouble talking (dysarthria), due to swollen mouth barely talk and it hurts for him to talk / pain (oral pain), had bumps on his eyes (eye disorder) and developed weak joints and muscles (muscular weakness), coughing (cough) and blood in poop (haematochezia), (unknown latency) following the administration of INFLUENZA QUADRIVAL A-B MULTIDOSE VACCINE PRESERVED.  The haematochezia was assessed as medically significant event and other reported events were assessed as non-serious events.   Details of laboratory data not reported.   Patient was treated with unknown treatment to numb down the pain, but it only numbed the pain and did not helped him for the swelling in his mouth.  On an unknown date, the patient had recovered from lung disorder and was recovering from oral pain. The patient had not recovered from mouth swelling, cough and dysarthria at the time of report. Event outcome was unknown for all other reported events.   Information on the batch number was requested.; Sender's Comments: This case involves a male patient (age unspecified) who experienced haematochezia, lung disorder (on first night), malaise, muscular and joint weakness, cough and mouth swelling with symptoms of oral discomfort and dysarthria after vaccination with FLUZONE. The time to onset was compatible. Further information regarding concurrent condition during vaccination, previous vaccination and tolerance, laboratory investigations excluding other alternative etiologies for the reported event are needed to fully assess this case. Based upon the reported information, the role of the suspect vaccine cannot be assessed.