The medication (Carbidopa-Levodopa ER 100mg) for Parkinson's disease ceased to work/doubled the med but it still doesn't work; could no longer walk or hold herself up on her two feet; could no longer walk or hold herself up on her two feet; exhausted; couldn't feed herself; sleep all the time; dose number: 3; This is a spontaneous report received from a non-contactable reporter(s) (Consumer or other non HCP). A 76 year-old female patient (not pregnant) received bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE), administered in arm left, administration date 08Oct2021 11:00 (Lot number: FF2589) at the age of 76 years as dose 3 (booster), single for covid-19 immunisation; carbidopa, levodopa (CARBIDOPA/LEVODOPA) (Batch/Lot number: unknown) at 100 mg for parkinson's disease. Relevant medical history included: "bi-polar" (unspecified if ongoing); "dementia" (unspecified if ongoing). The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose Number: 2; Lot No: EP6955; Arm Left; 10:00 AM), administration date: 17Mar2021, when the patient was 75 years old, for COVID-19 immunization; Bnt162b2 (Dose Number: 1; Lot No: EN6200; Arm Left; 10:30 AM), administration date: 24Feb2021, when the patient was 75 years old, for COVID-19 immunization. Prior to vaccination, the patient was not diagnosed with COVID-19. The patient had not received any other vaccine within 4 weeks prior to the COVID-19 vaccine.  The following information was reported: DRUG INEFFECTIVE (disability) with onset 09Oct2021, outcome "not recovered", described as "The medication (Carbidopa-Levodopa ER 100mg) for Parkinson's disease ceased to work/doubled the med but it still doesn't work"; GAIT INABILITY (disability), DYSSTASIA (disability) all with onset 09Oct2021, outcome "not recovered" and all described as "could no longer walk or hold herself up on her two feet"; FATIGUE (disability) with onset 09Oct2021, outcome "not recovered", described as "exhausted"; FEEDING DISORDER (disability) with onset 09Oct2021, outcome "not recovered", described as "couldn't feed herself"; HYPERSOMNIA (disability) with onset 09Oct2021, outcome "not recovered", described as "sleep all the time"; IMMUNISATION (non-serious) with onset 08Oct2021, outcome "unknown", described as "dose number: 3". The events "the medication (carbidopa-levodopa er 100mg) for Parkinson's disease ceased to work/doubled the med but it still doesn't work", "could no longer walk or hold herself up on her two feet", "could no longer walk or hold herself up on her two feet", "exhausted", "couldn't feed herself" and "sleep all the time" were evaluated at the physician office visit. The patient reported carbidopa/levodopa ER 100mg for Parkinson's disease ceased to work and patient could no longer walk or hold herself up on her two feet. She became exhausted and couldn't feed herself. She sleeps all the time. Her neurologist doubled the medication but it still doesn't work as of 07Dec2021. Therapeutic measures were taken as a result of drug ineffective, gait inability, dysstasia, fatigue, feeding disorder, hypersomnia. Since the vaccination, the patient has not been tested for COVID-19.  No follow-up attempts are possible. No further information is expected.