OFF LABEL DOSING FREQUENCY; PERICARDITIS; DIARRHEA; THROWING UP A LOT; This spontaneous report received from a parent concerned a 39 year old male of an unspecified race and ethnicity. The patient's height, and weight were not reported. The patient's past medical history included: orthopedic issues such as broken knees (due to football), and concurrent conditions included: sinus issues (complicated, needing surgery), and other pre-existing medical conditions included: The patient's father was diagnosed with pericarditis in his youth and also had sinus issues. The patient previously received dose 1 with covid-19 vaccine ad26.cov2.s (Dose number in series 1), (suspension for injection, route of admin, batch number and expiry date were not reported) dose was not reported, 1 total administered start therapy date were not reported for covid-19 prophylaxis. The patient did not have any issues following vaccination (Dose number in series 1). The patient previously received dose 2 with covid-19 vaccine ad26.cov2.s (Dose number in series 2), (suspension for injection, route of admin, batch number and expiry date were not reported) dose was not reported, 1 total administered start therapy date were not reported for covid-19 prophylaxis. The patient did not have any issues following vaccination (Dose number in series 2). The patient received dose 3 with covid-19 vaccine ad26.cov2.s (Dose number in series 3), (suspension for injection, route of admin, batch number and expiry date were not reported) dose was not reported, 1 total administered on 10-AUG-2022 for covid-19 prophylaxis which was an off label dosing frequency (Dose number in series 3). The drug was associated with Off label use. Age at time of vaccination 39 years old. The batch number was not reported and has been requested. No concomitant medications were reported.  On an unspecified date in AUG-2022, the patient experienced GI (Gastrointestinal) symptoms (diarrhea, and throwing up a lot), (Dose number in series 3). On an unspecified date in AUG-2022, the patient experienced pressure in his chest and chest pain (Dose number in series 3). The pain subsided when leaning over the couch but came back once he got back up. On 16-AUG-2022, the patient went to the ER (emergency room), where he was being assessed and running tests. ER doctors said that he had an irregular EKG and mild to severe symptoms of pericarditis (Dose number in series 3). Laboratory data included: Electrocardiogram irregular. On 14-AUG-2022, Laboratory data included: COVID-19 virus test Negative. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from throwing up a lot and diarrhea on AUG-2022 (duration was 3 days), had not recovered from pericarditis, and the outcome of off label dosing frequency was not reported. This report was serious (Other Medically Important Condition).; Sender's Comments: V0: 20220833937-covid-19 vaccine ad26.cov2.s-Pericarditis. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and is scientifically plausible. There is no information on any other factors potentially associated with the event(s). Therefore, this event(s) is considered related.