Also has current left quad tear under investigation with no know instigating trauma.; dehydration; increasingly poor appetite/taste; increasingly poor appetite/taste; poor intake; weight loss/30 weight loss overall cachectic; short breath; poor sleeping but extreme fatigue and sleeping day and night; extreme fatigue / lassitude; periods of shivering; disorientation; finally confusion; grouchy; tremor; mumbling; Parkinsonian gait; This is a spontaneous case from a contactable physician. This physician reported similar events under different doses. This is the second report of two reports for dose 3.   An 87-year-old male patient received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE), dose 3 via intramuscular in left arm on 31Aug2021 at patient age of 87-year-old, as single dose (Lot Number: EW0168) for COVID-19 immunisation. The patient was not diagnosed with COVID-19 prior to vaccination. The patient medical history included heart transplant with immunosuppression tacrolimus stable. The patient had none known allergies. The patient concomitant medications were reported yes, but unspecified.  The patient previously received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE), dose 1 via intramuscular in left arm on 04Jan2021 at patient age of 86-year-old as single dose (Lot Number: EL3246) for COVID-19 immunisation. The patient previously received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE), dose 2 via intramuscular in left arm on 25Jan2021 at patient age of 86-year-old as single dose (Lot Number: EL9262) for COVID-19 immunisation. The patient did not receive any other vaccines within 4 weeks prior to the COVID vaccine. By mid-Feb2021 if not sooner, after the first 2 vaccines in Jan2021, increasingly poor appetite/taste, poor intake, weight loss, short breath, poor sleeping but extreme fatigue and sleeping day and night, periods of shivering, lassitude, disorientation, and finally confusion, grouchy, tremor, mumbling, Parkinsonian gait. 30# weight loss overall cachectic. Overlay on stable health 12-year post heart transplant on stable immunosuppression regimen. Workup above symptoms found small cell lymphoma. Prior to CA oral med begun 5 months after first two vaccines, symptoms abruptly reversed and slowly regaining all usual physical and cognitive abilities, gait, demeanor, sensorium and weight up 10 pounds over 2 months until same effect began again slowly about 1 month following COVID-19 dose 3. Again same disabilities. The patient also reported good tumor response (on acalabrutinib), current left quad tear under investigation with no known instigating trauma. Tumor load steadily improving. Labs stable but dehydration needing IV infusion. Temporal relationship is striking. Realize very complex situation but no other explanation found. Blood test with Roche Elecsys Anti-SARS-CoV-2 S and SARS COV 2 AB, TOTAL SPIKE SEMI QN on 03Nov2021 was negative. The events were reported as non-serious by reporter. The event resulted in doctor or other healthcare professional office/clinic visit. The outcome of the event left quad tear was not resolved. The outcome of the other events was unknown.; Sender's Comments: As there is limited information in the case provided, the causal association between the events and the suspect drug BNT162B2cannot be excluded. The case will be reassessed once new information is available.  The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate.,Linked Report(s) : US-PFIZER INC-202101548855 as same reporter/patient/drug, different dose/event.