SUSPECTED COVID-19 INFECTION; SUSPECTED CLINICAL VACCINATION FAILURE; This spontaneous report received from a pharmacist via other manufacturer (Pfizer) concerned a 64 year old male.  Initial information was processed along with additional information on 29-JUN-2022. The patient's height, and weight were not reported. The patient's past medical history included: B12 deficiency, and insomnia, and concurrent conditions included: coronary artery disease (CAD), diabetes mellitus (DM), hypertension (HTN), hypersensitivity lung disease (HLD), gastroesophageal reflux disease (GERD), seizure disorder, HA and drug allergy (Drug not reported). The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 043A21A expiry: UNKNOWN) 1 total, dose was not reported, administered on 17-MAY-2021 at right arm for prophylactic vaccination. Age at time of vaccination 63 years old.  Concomitant medications included guaifenesin for diabetes mellitus, ammonium lactate, ascorbic acid, cetirizine, clopidogrel, cyanocobalamin, empagliflozin, hydrochlorothiazide, insulin aspart/insulin degludec, insulin glargine, isopropanol/paraffin/sodium/stearyl alcohol, isosorbide, levetiracetam, metformin hydrochloride, methocarbamol, metoprolol tartrate, pantoprazole, salbutamol, salicylic acid, semaglutide, and vitamin E NOS.  On 10-JUN-2022, the patient was evaluated in ER (emergency room) for COVID (suspected covid-19 infection and suspected clinical vaccination failure) and was sent home with Paxlovid and dexamethasone. The patient was prescribed with non-company suspect drug Paxlovid (form of admin not reported and oral, batch number: 1917018A, expiry: Unknown) dose not reported, administered on an unknown date in JUN-2022 for covid-19. Treatment with Paxlovid was stopped on 13-JUN-2022.  On 20-JUN-2022, the patient had worsening SOB (shortness of breath) and pulse and oxygen was less than 88 percent due to which patient was hospitalized on same day (number of days hospitalization were not reported) and patient was given supplemental oxygen (nasal cannula).  The action taken with covid-19 vaccine ad26.cov2.s was not applicable and with paxlovid was drug discontinued. The outcome of the suspected clinical vaccination failure and suspected covid-19 infection was not reported. This report was serious (Hospitalization Caused / Prolonged). This report was associated with a product quality complaint: 90000238646.; Sender's Comments: V0- 20220657376-Covid-19 Vaccine. Ad26.Cov2.S-Suspected Covid-19 infection. 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. 20220657376-Covid-19 Vaccine. Ad26.Cov2.S-Suspected clinical vaccination failure. 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. Therefore, this event(s) is considered not related.