COVID-19 PNEUMONIA; HYPOXIA; TYPE 1 DIABETES MELLITUS; TYPE 2 DIABETES MELLITUS; TROPONIN INCREASED; HYPERGLYCAEMIA; HYPONATRAEMIA; SUSPECTED CLINICAL VACCINATION FAILURE; This spontaneous report received from a health care professional via a Regulatory Authority VAERS (Vaccine Adverse Event Reporting System) concerned a 72 year old male of unspecified race and ethnicity. The patient's height, and weight were not reported. No past medical history or concurrent conditions were reported. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin, and batch number were not reported) dose was not reported, 1 total administered, on 29-APR-2021 for product use for unknown indication. The batch number was not reported. The Company is unable to perform follow-up to request batch/lot numbers. No concomitant medications were reported.  On 28-SEP-2021, the patient experienced pneumonia due to covid-19 (suspected clinical vaccination failure), hypoxia (hypoxemia), type 2 diabetes mellitus with hyperglycemia with long term current use of insulin along with hyponatraemia and type 1 diabetes mellitus. The patient also underwent laboratory test for troponin which was found to be elevated. The patient was hospitalized (date unspecified) for unspecified duration. Treatment medications (dates unspecified) included: insulin. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient had not recovered from covid-19 pneumonia, hyperglycaemia, hyponatraemia, hypoxia, troponin increased, type 1 diabetes mellitus, and type 2 diabetes mellitus, and the outcome of suspected clinical vaccination failure was not reported. This report was serious (Hospitalization Caused / Prolonged). This report was associated with product quality complaint: 90000197204. The suspected product quality complaint has been confirmed to be the reported allegation could not be confirmed. A manufacturing related root cause could not be identified based on the PQC evaluation/investigation performed.  Additional information received from Central Complaint Vigilance department on 19-OCT-2021. The following information was updated and incorporated into the case narrative: Product quality complaint investigation result was added.; Sender's Comments: V1: Additional version updates - Product quality complaint investigation result. This updated information does not alter the causality of previously reported event.  20211017344-Covid-19 vaccine ad26.cov2.s- Covid-19 pneumonia,  Hypoxia, Type 1 diabetes mellitus,  Type 2 diabetes mellitus, Troponin increased,  Hyperglycaemia,  Hyponatraemia,. This event(s) is considered unassessable. 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).  20211017344-Covid-19 vaccine ad26.cov2.s-suspected clinical vaccination failure. This event(s) is considered not related. 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: SPECIAL SITUATIONS