Initial information received on 13-Mar-2021 regarding an unsolicited valid serious literature full article case from another health care professional.   A literature article:  This case is linked to cases 2021SA091226, 2021SA091252, 2021SA091271, 2021SA091286, 2021SA091303, 2021SA091334, 2021SA091349, 2021SA091366, 2021SA091398, 2021SA091448, 2021SA091489, 2021SA091516, 2021SA091556, 2021SA091604, 2021SA091690, 2021SA091745, 2021SA091782, 2021SA091798, 2021SA091833, 2021SA091855 and 2021SA091879. (Same Literature article)  Abstract: On October 7, 2016, the Food and Drug Administration approved recombinant hemagglutinin quadrivalent influenza vaccine (RIV4) (Spodoptera frugiperda cell line; Flublok Quadrivalent) for active immunization for the prevention of influenza disease in individuals 18 years of age and older. Clinical trials did not reveal any major differences in adverse events or serious adverse events following Flublok Quadrivalent versus standard dose quadrivalent inactivated influenza vaccine. To improve our understanding of the safety profile of this vaccine, we reviewed and summarized adverse event reports after Flublok Quadrivalent administration to the vaccine adverse event reporting system (VAERS). Through June 30, 2020, VAERS received 849 reports after RIV4 vaccination. The vast majority (810; 95%) were nonserious. Among serious events, there were 10 cases of Guillain-Barre syndrome, including 5 people who required mechanical ventilation and 2 people who died. Many allergic reactions were reported as non-serious, but required interventions to treat a life-threatening event, example: epinephrine, nebulizers, albuterol, glucocorticoids, and supplemental oxygen. Two people experienced a positive rechallenge (which are allergic reactions after repeated vaccination with RIV4), including a person who despite premedication with antihistamines developed respiratory difficulties, required epinephrine, and was transported to the emergency department. The occurrence of anaphylaxis and other allergic reactions in some individuals may reflect an underlying predisposition to atopy that may manifest itself after an exposure to any drug or vaccine and does not necessarily suggest that Flublok Quadrivalent is particularly allergenic. Post marketing safety surveillance will continue to be vital for understanding the benefits and risks of quadrivalent recombinant influenza vaccine.  This case involves a 65 years old female patient who experienced pulmonary abscess (lung abscess), intraparenchymal hemorrhage (cerebral haemorrhage), 60 to 70 percent stenosis of the coronary arteries (coronary artery stenosis), pulseless electrical activity, cardiogenic shock, aspiration event (aspiration) and takotsubo cardiomyopathy (stress cardiomyopathy), after she received INFLUENZA QUADRIVALENT RECOMBINANT VACCINE [FLUBLOK QIV].  Past medical treatment, vaccination, family history and concomitant medication were not reported.  At the time of the event, the patient had ongoing medical history of chronic obstructive pulmonary disease, coronary artery disease, hypothyroidism, depression, gastroesophageal reflux disease and hepatic cirrhosis.  On an unknown date, the patient received a dose of suspect INFLUENZA QUADRIVALENT RECOMBINANT VACCINE [batch number, expiry date and other dosing details were not reported] for prophylactic vaccination.  On an unknown date, the patient developed a serious pulseless electrical activity, takotsubo cardiomyopathy (stress cardiomyopathy), cardiogenic shock, aspiration event (aspiration), intraparenchymal hemorrhage (cerebral haemorrhage) and pulmonary abscess (lung abscess), 7 weeks following the administration of INFLUENZA QUADRIVALENT RECOMBINANT VACCINE.   The patient was resuscitated, hospitalized on an unknown date for the reported events and stabilized.  On an unknown date, the patient developed a serious 60 to 70 percent stenosis of the coronary arteries (coronary artery stenosis), (unknown latency) following the administration of INFLUENZA QUADRIVALENT RECOMBINANT VACCINE and no intervention was performed. Patient was hospitalized during this event.   Relevant laboratory test results included: On an unknown date: Catheterization cardiac- cardiac catheterization revealed 60-70 percent stenosis of the coronary arteries.  It was not reported if the patient received any corrective treatment.  At the time of reporting, event outcome was not reported for all the reported events.   There will be no information available on the batch number for this case.; Sender's Comments: This case involved a 65 years old female patient who presented with coronary artery stenosis, lung abscess, cerebral haemorrhage, pulseless electrical activity, cardiogenic shock, aspiration and stress cardiomyopathy after the administration of FLUBLOK QIV. Time of onset was unknown for coronary artery stenosis and compatible for remaining reported events. At the time of the event, the patient had ongoing chronic obstructive pulmonary disease, coronary artery disease, hypothyroidism, depression, gastroesophageal reflux disease and hepatic cirrhosis. Cardiac catheterization was performed which revealed serious 60-70% stenosis of the coronary arteries. Further information regarding previous vaccination/treatment and tolerance, other laboratory investigations excluding 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.