crohn's flare up; This is a spontaneous report from a contactable consumer or other non health care professional (patient).  A 54-year-old male patient received second dose of bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE; Formulation: Solution for injection, Batch/Lot number: EP6955, Expiration Date: 30Jun2021, NDC number: Unknown), via an unspecified route of administration in right shoulder on 14Apr2021 (at the age of 54-year-old) as single dose for COVID-19 immunisation. The patient medical history included crohn's disease (Diagnosed over 20 years ago). Concomitant medications included mesalazine (LIALDA) taken for crohn's disease; omeprazole magnesium (PRILOSEC [OMEPRAZOLE MAGNESIUM]) taken for gastrooesophageal reflux disease; both from an unknown date and unknown if ongoing. The patient previously received the first dose of bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE; Formulation: Solution for injection, Batch/lot number: EP6955, expiration date: 30Jun2021, NDC number: Unknown) via an unspecified route of administration in left shoulder on 24Mar2021 for COVID-19 immunization and experienced joint pain. It was reported that, the patient was calling about the covid vaccine. The patient was diagnosed with Crohn's disease over 20 years ago and it had been in remission for the last 15 years. The patient was weaning off some of the medications with the doctors permission, Lialda. The patient can't remember when symptoms started to return but it closely corresponded with when the patient was vaccinated. The patient had a Crohn's flare up and was out of work for a month. The patient has been seeing his GI doctor for the treatment of his flare up but declines to provide the doctor's information. The patient is getting close to getting his Crohn's back into remission, his blood work on 21Jun2021 showed that it is almost there. The patient was unsure when the symptoms started coming on. The joint pain started right around the first dose and then he got the second shot in the middle of April. The symptoms were getting increasingly worse at the end of May and then the middle of May is when they started changing up the mediations. The patient also had blood work on 27May2021. On 21Jun2021 the patient had blood work, probably a complete blood panel. It also measured the patient CRP number which is supposed to be 0-3 for when you're in remission. At the end of May the patient CRP was 138.6 and on 21Jun2021 it was 3.6. Now that the patient is back on medication it is getting better. The seriousness of chron's flare was reported as unspecified. The patient underwent lab tests and procedures which included blood test: unknown on 27May2021 and unknown on 21Jun2021, c-reactive protein: 138.6 on 27May2021 and 3.6 on 21Jun2021. The outcome of the event was resolving.  Description of Product Complaint: The caller was diagnosed with Crohn's disease over 20 years ago and it had been in remission for the last 15 years. The caller was weaning off some of the medications with the doctors permission, Lialda. The caller can't remember when symptoms started to return but it closely corresponded with when the caller was vaccinated. The caller had a Crohn's flare up and was out of work for a month. Lialda lot, NDC, and expiration date not probed as it is not a Pfizer product.  Information on Lot/Batch number was available. Additional information has been requested.