This spontaneous report received from a health care professional by a Regulatory Authority, Vaccine Adverse Event Reporting System (VAERS Inbound Unit) concerned a 74 year old female of an unspecified race and ethnicity. The patient's height, and weight were not reported. The patient's past medical history included: compression fracture of T12 (twelfth thoracic) vertebra, and deep vein thrombosis (DVT) of lower extremity, and concurrent conditions included: X-Ray showed lytic lesion of bone, malignancy breast, anxiety, depression, B12 deficiency, iron deficiency anemia due to chronic blood loss, anemia in stage 4 chronic kidney disease, lambda light chain myeloma, stage 3b chronic kidney disease, chemotherapy induced thrombocytopenia, leukopenia due to antineoplastic chemotherapy, severe protein calorie malnutrition, vitamin D deficiency, antineoplastic chemotherapy induced pancytopenia, refractory anemia with excess of blasts 1, failure to thrive in adult (FTT) and drug allergy (Flomax). The patient received Covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 042A21A, expiry: unknown) dose was not reported, single dose, 1 total administered on 14-JUN-2021 for an unspecified indication. Age at time of vaccination 74 years old. The latency was 303 days. Concomitant medications included colecalciferol, dexamethasone, fludrocortisone acetate, folic acid, lenalidomide, omeprazole, and venlafaxine hydrochloride. On 10-APR-2022, the patient had a COVID-19 PCR (polymerase chain reaction) test which detected Covid-19. On 13-APR-2022, the patient was admitted with Covid-19 pneumonia which quickly progressed to the need for HFNC (high flow nasal cannula) despite treatment with steroid. The patient experienced severe thrombocytopenia and was not safe to add anticoagulation despite platelet transfusion. The patient experienced advanced multiple myeloma (coded as plasma cell myeloma) and was on chemotherapy, condition aggravated and was sars-cov-2 (severe acute respiratory syndrome coronavirus 2) test positive. On 13-APR-2022, the patient had a sudden death and died from hypoxia. It was unknown if an autopsy was performed. The action taken with Covid-19 vaccine ad26.cov2.s was not applicable. The patient died of sudden death, hypoxia, plasma cell myeloma, Covid-19 pneumonia, thrombocytopenia, Covid-19, condition aggravated, sars-cov-2 test positive, chemotherapy and platelet transfusion on 13-APR-2022. This report was serious (Death). This report was associated with a product quality complaint. The suspected product quality complaint has been confirmed to be the reported allegation was not confirmed and the root cause was determined to be not manufacturing related, batch and lot tested and found within specifications based on the product quality complaint evaluation/investigation performed. Additional information received from Complaint Department on 10-JUN-2022. The following information was updated and incorporated into the case narrative: Product quality complaint number and investigation result. Upon review, the following information was corrected: event level medically confirmed corrected to blank from yes. Sender's Comments: V2 Additional information in this version updates of Product quality complaint number and investigation result. Upon review, the following information was corrected: event level medically confirmed corrected to blank from yes. This updated information does not change the prior causality assessment of reported events. Covid-19 vaccine ad26.cov2.s- Sudden death, Covid-19 pneumonia, Covid-19, condition aggravated, sars-cov-2 test positive, Hypoxia, The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s). Therefore, this event(s) is considered unassessable. Covid-19 vaccine ad26.cov2.s-Plasma cell myeloma, chemotherapy. The event(s) shows an incompatible temporal relationship. Therefore, this event(s) is considered not related. (Additionally patient has medical history of light chain Myeloma). Covid-19 vaccine ad26.cov2.s-Thrombocytopenia, platelet transfusion. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There are other factors more likely to be associated with the event(s) than the drug. Specifically: MEDICAL HISTORY. Therefore, this event(s) is considered not related.(Also patient has medical history of chemotherapy induced thrombocytopenia); Reported Cause(s) of Death: HYPOXIA.