I only got the first dose because of the symptoms; Elevated levels of anti-cdtb ab indicating irritable bowel syndrome; Constipation; Bloating; Stomach issues; Diarrhea; Case reference number US-BN-2022-004184 is a spontaneous case report initially received on 18-Oct-2022 from a consumer (reference number: USBAV22-1735) and concerns 35-year-old male patient.  *The patient's concomitant medication included Wellbutrin (bupropion hydrochloride), Metamucil (plantago ovata), multivitamin (as reported, brand name unknown), iron (iron), vitamin D3 (vitamin D3), SAM-E (ademetionine), magnesium (magnesium), Align probiotic (Bifidobacterium infantis) and Crestor (rosuvastatin calcium).*  *The patient had no medical history.*  On 06-Aug-2022, the patient was vaccinated with the first dose of Imvamune vaccine (Smallpox and Monkeypox Vaccine Modified Vaccinia Ankara-Bavarian Nordic (live-attenuated, non-replicating); batch number: P00021) at a dose reported as 'single dose', administered subcutaneously, in the right arm, for monkeypox prophylaxis.  On 07-Aug-2022, one day after the first dose of Imvamune, the patient started having stomach issues, constipation, diarrhea and bloating, and the patient stated that was 'a roller coaster of not knowing what to expect'. The patient firstly thought it would subside, however, 2 months passed, and it was still in the same spot in terms of issues and symptoms. The patient mentioned reporting this to VAERS, but there was no response about it from government. The patient mentioned receiving only the first dose because of the symptoms (explicitly codded as 'missed dose').  In addition, the patient stated he had the change his diet to low fodmap diet, and at the time of report could not consume his normal diet without return of symptoms.  On an unspecified date, stool samples were taken, and results were all normal (no parasites and no bacteria) and antibody test were performed and showed elevated levels of anti-cdtb-ab indicating irritable bowel syndrome, other tests were in progress. It was stated that endoscopy and colonoscopy were scheduled for the 'next week'.  It was also stated that upping the amount of probiotic and metamucil was the treatment for the reported events.  At the time of this report, the outcome for the events of 'abdominal discomfort', 'constipation', abdominal distension' and 'diarrhoea' was resolving and for the event 'irritable bowel syndrome' was unknown.  The reporter assessed the events of 'abdominal discomfort', 'constipation', abdominal distension' and 'diarrhoea' as non-serious and possibly related to Imvamune. The reporter did not provide seriousness and causality assessment for the event 'irritable bowel syndrome'.  This case is linked to case number US-BN-2022-004186 (the same reporter).  Additional information received from Bavarian Nordic on 19-Oct-2022 included local case ID.  All follow-up information is blended into the case narrative above, with the latest information presented between asterisks (*).  Follow-up information received on 09-Nov-2022 from a consumer via Bavarian Nordic: New information included details for the patient, additional information for the administered Imvamune vaccine, additional laboratory data, confirmation that the second dose was not administered and that were no known direct adverse events from missing the dose.  Non-significant case correction received on 16-Nov-2022 and included new reference number.  Follow-up information received on 18-Nov-2022 from a consumer via Bavarian Nordic: New information included patient's concomitant medication, confirmation that patient had no medical history and outcome of reported events 'abdominal discomfort', 'constipation', abdominal distension' and 'diarrhoea'.; Reporter's Comments: A 35-year-old male patient developed non-serious events stomach issues, constipation, diarrhea and bloating on the day 1 following vaccination with the first dose of Imvamune for monkeypox prophylaxis. Antibody test was performed and indicated irritable bowel syndrome. Due to reported symptoms, the patient only received the first dose which is considered a missed dose. The events of constipation, irritable bowel syndrome and bloating are unlisted per the insert for Imvamune, whereas the events of stomach issues and diarrhea are listed but unlisted per the package insert. Missed dose is listed per conventions. Reportedly, stool samples were taken, and results were normal, endoscopy and colonoscopy were scheduled. The patient stated that treatment received were probiotic and metamucil. The outcome for the events of abdominal discomfort, constipation, abdominal distension and diarrhoea was resolving and for the event irritable bowel syndrome was unknown. The patient had no medical history, and concomitant medication included Wellbutrin, Metamucil, multivitamin, iron, vitamin D3, SAM-E, magnesium, Align probiotic and Crestor. Based on information currently provided and known safety profile of the vaccine causality cannot be excluded, therefore events are assessed as related to the Imvamune vaccine. Missed dose is assessed as not related to the suspect vaccine, but to a human factor. This case is considered as non-serious.; Sender's Comments: A 35-year-old male patient developed non-serious events stomach issues, constipation, diarrhea and bloating on the day 1 following vaccination with the first dose of Imvamune for monkeypox prophylaxis. Antibody test was performed and indicated irritable bowel syndrome. Due to reported symptoms, the patient only received the first dose which is considered a missed dose. The events of constipation, irritable bowel syndrome and bloating are unlisted per the package insert for Imvamune, whereas the events of stomach issues and diarrhea are listed but unlisted per the package insert. Missed dose is listed per conventions. Reportedly, stool samples were taken, and results were normal, endoscopy and colonoscopy were scheduled. The patient stated that treatment received were probiotic and metamucil. The outcome for the events of abdominal discomfort, constipation, abdominal distension and diarrhoea was resolving and for the event irritable bowel syndrome was unknown. The patient had no medical history, and concomitant medication included Wellbutrin, Metamucil, multivitamin, iron, vitamin D3, SAM-E, magnesium, Align probiotic and Crestor. Based on information currently provided and known safety profile of the vaccine causality cannot be excluded, therefore events are assessed as related to the Imvamune vaccine. Missed dose is assessed as not related to the suspect vaccine, but to a human factor. This case is considered as non-serious.