deep vein thrombosis in left leg; severe anaphylactic reaction; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP). Other Case identifier(s): 20220534919(0.0).  A 45-year-old male patient received BNT162b2 (BNT162B2), as dose 1, single (Batch/Lot number: unknown) and as dose 2, single (Batch/Lot number: unknown) at the age of 45 years for covid-19 immunisation; coviD-19 vaccine janssen (COVID-19 VACCINE JANSSEN), on 19Jan2022 as dose 3 (booster), single (Lot number: 1855191, Expiration Date: 11Apr2022), in arm for covid-19 immunisation. The patient's relevant medical history included: "Multiple sclerosis" (ongoing); "Alcohol use" (ongoing), notes: occasional average one drink per month; "Nonsmoker" (ongoing); "Allergy to NSAIDs" (ongoing); "Latex allergy" (ongoing), notes: latex-mild allergy; "Drug allergy" (ongoing), notes: Interferon Beta A-1; "interchange of vaccine product", start date: 19Jan2022, stop date: 19Jan2022, notes: Johnson & Johnson COVID vaccine. The patient's concomitant medications were not reported. The following information was reported: DEEP VEIN THROMBOSIS (hospitalization, medically significant) with onset Feb2022, outcome "recovering", described as "deep vein thrombosis in left leg"; ANAPHYLACTIC REACTION (medically significant) with onset Feb2022, outcome "unknown", described as "severe anaphylactic reaction". The patient was hospitalized for deep vein thrombosis (start date: 27Apr2022, discharge date: 29Apr2022, hospitalization duration: 2 day(s)). The event "deep vein thrombosis in left leg" required physician office visit and emergency room visit. Therapeutic measures were taken as a result of deep vein thrombosis.   Clinical course: The patients height, and weight were not reported. The patients concurrent conditions include: multiple sclerosis, alcohol user (occasional average one drink per month), non-smoker, Mobic allergy, latex-mild allergy, and drug allergy (Interferon Beta A-1). The Patient had no drug abuse or illicit drug usage. On an unspecified date, the patient was previously received Pfizer biontech covid-19 vaccine (tozinameran) (Dose number series 1) (form of admin, route of admin, and batch number were not reported, expiry: unknown) dose was not reported, administered for prophylactic vaccination. On an unspecified date, following vaccination with Pfizer biontech covid-19 vaccine (tozinameran), the patient experience severe anaphylactic reaction (dose number in series 1). The patient additionally received booster dose of covid-19 vaccine ad26,cov2.s (dose number in series 2) (suspension for injection, route of admin not reported, batch number: 1855191 expiry: 11Apr2022) dose was not reported, 1 total administered in arm on 19Jan2022 for prophylactic vaccination. Age at time of vaccination 45 year old. No concomitant medication were reported. Patient reported that he first notice something with his leg in mid Feb2022, and then it become worse in late Mar2022 to early Apr2022 (dose number in series 2). The patient was transported to emergency room. The patient experience deep vein thrombosis in left leg (dose number in series 2). On 27Apr2022, the patient was admitted to hospital. On 29Apr2022, patient was discharged after having the blood clot removed (dose number series 2). The patient was hospitalized for three days. On around 02May2022 or 03May2022, the patient followed up with her PCP (primary care physician). The patient visited physician office and emergency room. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient was recovering from deep vein thrombosis in left leg. The report was serious (hospitalization caused/prolonged). V0: # Covid-19 vaccine ad26.cov2.s deep vein thrombosis in left leg. The events has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors parentally associated with the events. Therefore this events is considered unassessable.  No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.