might be Lyme disease, as the initial Lyme blood screen was highly inaccurate.; RA factor came back positive; my body was fighting some type of infection; knee "blew up" and developed I fluid on my knee; left elbow would not straighten out completely; Hematocrit 38.2 low; haemoglobin 12.5 low; RBC 4.38 low; sedimentation rate 77 way high; C-reactive protein 147.60/ 98.55/ very high; Cyclic citrollinated peptide 202 very high; low anion gap; Body aches; joint inflammation; swollen left knee; aggravate my left side back/hip/leg pain; joint inflammation and pain. This included fingers, right wrist, left elbow, left hip / aggravate my left side back/hip/leg pain; fever; aggravate my left side back/hip/leg pain; The initial safety information received was reporting only non-serious adverse drug reactions. Upon receipt of follow-up information on [22Nov2021], this case now contains serious adverse reactions. Information processed together  This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 50 year-old male patient received bnt162b2 (BNT162B2), administered in arm right, administration date 07May2021 (Lot number: EW0172) at the age of 50 years as dose 2, single for covid-19 immunisation. Relevant medical history included: "Morton's Neuromas", start date: 01Apr2021 (ongoing), notes: in right foot; "limp", start date: Apr2021 (unspecified if ongoing); "foot pain", start date: Apr2021 (unspecified if ongoing), "allergies", "pain". Family history included: "RA" (unspecified if ongoing), notes: patient's father. Prior to vaccination, the patient was not diagnosed with COVID-19. Concomitant medications included: loratadine taken for hypersensitivity, start date: 15Mar2021, stop date: 01Nov2021; fish oil; boswellia complex; ligaplex i; naproxen sodium taken for pain, start date: 01Apr2021 (ongoing). The patient did not receive any other vaccines within 4 weeks prior to the vaccination. Vaccination history included: Bnt162b2 (Dose: 1st, Dose lot number=EW0150, Dose vaccine location=Left arm), administration date: 09Apr2021, when the patient was 50 years old, for COVID-19 immunization, reaction(s): "lower left back and hip started to hurt", "leg pain". The following information was reported: LYME DISEASE (medically significant), outcome "unknown", described as "Lyme disease"; RHEUMATOID FACTOR POSITIVE (medically significant), outcome "unknown", described as "RA factor came back positive"; PAIN (medically significant) with onset May2021, outcome "recovered" (2021), described as "Body aches"; ARTHRITIS (medically significant) with onset May2021, outcome "not recovered", described as "joint inflammation"; JOINT SWELLING (medically significant) with onset May2021, outcome "not recovered", described as "swollen left knee"; PAIN IN EXTREMITY (medically significant), ARTHRALGIA (medically significant) all with onset May2021, outcome "not recovered" and all described as "joint inflammation and pain. This included fingers, right wrist, left elbow, left hip / aggravate my left side back/hip/leg pain"; CONDITION AGGRAVATED (medically significant) with onset May2021, outcome "not recovered", BACK PAIN (medically significant), outcome "unknown" and all described as "aggravate my left side back/hip/leg pain"; JOINT EFFUSION (medically significant), outcome "unknown", described as "knee "blew up" and developed I fluid on my knee"; JOINT RANGE OF MOTION DECREASED (medically significant), outcome "unknown", described as "left elbow would not straighten out completely"; INFECTION (non-serious), outcome "unknown", described as "my body was fighting some type of infection"; PYREXIA (non-serious), outcome "recovered", described as "fever"; C-REACTIVE PROTEIN INCREASED (non-serious) with onset 27Jul2021, outcome "unknown", described as "C-reactive protein 147.60/ 98.55/ very high"; ANTI-CYCLIC CITRULLINATED PEPTIDE ANTIBODY POSITIVE (non-serious) with onset 27Jul2021, outcome "unknown", described as "Cyclic citrollinated peptide 202 very high"; ANION GAP DECREASED (non-serious) with onset 27Jul2021, outcome "unknown", described as "low anion gap"; HAEMATOCRIT DECREASED (non-serious) with onset 10Sep2021, outcome "unknown", described as "Hematocrit 38.2 low"; HAEMOGLOBIN DECREASED (non-serious) with onset 10Sep2021, outcome "unknown", described as "haemoglobin 12.5 low"; RED BLOOD CELL COUNT DECREASED (non-serious) with onset 10Sep2021, outcome "unknown", described as "RBC 4.38 low"; RED BLOOD CELL SEDIMENTATION RATE INCREASED (non-serious) with onset 10Sep2021, outcome "unknown", described as "sedimentation rate 77 way high". The clinical course was as follows: In early Apr2021, the patient had some right foot pain, which the patient did not think too much of as he had Morton's Neuromas in the right foot. The patient started to limp around. Then, the patient got the first dose of vaccine and had no significant side effects. Because of the limping, the lower left back and hip started to hurt, the patient was favoring the left leg over the right due to the foot pain. The patient saw both the podiatrist and orthopedic for the foot and back/hip/leg pain. The podiatrist was seen before both COVID shots. The orthopedic was seen in between the first and second shot. Orthopedic prescribed physical therapy (PT) which was started before the 2nd COVID shot, on 19Apr2021. The 2nd COVID shot did cause severe body aches and fever. This lasted about 48 hours but seemed to aggravate the left side back/hip/leg pain. It started out as body aches but very gradually increased into joint inflammation and pain. This included fingers, right wrist, left elbow, left hip and swollen left knee. As PT progressed, the pain started to get worse. The left knee "blew up" and the patient developed fluid on the knee. The right wrist began to hurt. The left elbow would not straighten out completely. The patient went back to the orthopedic and he prescribed a 5-day course of 20 units twice daily of prednisone to see if they could knock the inflammation down. lt worked, but as-soon as the patient came off the pills, the pains returned. The patient received a cortisone injection on 24May2021 for Morton Neuroma. The orthopedic recommended seeing a doctor and having blood tests run for something else. They thought Lyme was a possibility, as the patient lived in a forest with various animals that were known to carry ticks and Lyme. PT was stopped as that was not helping. The blood test run by the family doctor came back showing no Lyme, but indicated the body was fighting some type of infection. The family MD recommended the patient see a rheumatoid specialist as the RA factor came back positive. Prior to this episode, the patient was an active 50-year-old who played basketball (prior to Covid) weekly, lifted weights, took walks, and runs. All X-Rays or MRI came back with the same results, no physiological reasons why the joints were hurting. The patient was currently on hydroxychloroquine and various inflammation fighting supplements. In addition, the patient started a course of doxycycline to see if what the patient had might be Lyme disease, as the initial Lyme blood screen was highly inaccurate. The events "lyme disease", "RA factor came back positive", "body aches", "joint inflammation", "swollen left knee", "joint inflammation and pain. this included fingers, right wrist, left elbow, left hip / aggravate my left side back/hip/leg pain", "joint inflammation and pain. this included fingers, right wrist, left elbow, left hip / aggravate my left side back/hip/leg pain", "aggravate my left side back/hip/leg pain", "knee "blew up" and developed i fluid on my knee" and "left elbow would not straighten out completely", "my body was fighting some type of infection" were evaluated at the physician office visit. The patient underwent the following laboratory tests and procedures: antinuclear antibody: (27Jul2021) negative; c-reactive protein: (27Jul2021) 147.60, notes: way high; (10Sep2021) 98.55, notes: way high; full blood count: (27Jul2021) high, notes: immature grans auto % - 1.3 immature grans automated - 0.14; haematocrit: (10Sep2021) 38.2, notes: low; haemoglobin: (10Sep2021) 12.5, notes: low; investigation: (27Jul2021) 1:16, notes: Valve; (27Jul2021) 202, notes: way high; (16Jul2021) cortisone injected, notes: Cell count elevated - not infectious level - 27675; (2021) unknown, notes: Currently being tested for RA due to symptoms; (19Jul2021) none; magnetic resonance imaging: (17May2021) locate neuromas, notes: MRI of Foot; (13Jul2021) normal fluid on knee, notes: Knee + thigh; metabolic function test: (27Jul2021) 4.0, notes: Low Anion gap; red blood cell count: (10Sep2021) 4.38, notes: low; red blood cell sedimentation rate decreased: (10Sep2021) 77, notes: way high; rheumatoid factor: (unspecified date) positive; sars-cov-2 test: (Sep2021) negative, notes: Post vaccination; (Oct2021) negative, notes: Post vaccination; white blood cell count: (27Jul2021) 11.2, notes: High; x-ray: (10Jun2021) normal, notes: Lower back; (26Jun2021) normal, notes: Knee. Therapeutic measures were taken as a result of lyme disease, pain, arthritis, joint swelling, arthralgia, condition aggravated, back pain, joint effusion, joint range of motion decreased.  Follow-up attempts are completed. No further information is expected.