was going to pass out/Loss of consciousness; was going to pass out/Loss of consciousness/hx of passing out remote in distant past; started to feel very strange/No hearing or vision loss, just a general strange and uncomfortable feeling.; deep dreaming, then awoke feeling poorly; deep dreaming, then awoke feeling poorly; shaking; chills; BNT162B2 used in a Breastfeeding Mother; BNT162B2 used in a Breastfeeding Mother; This is a spontaneous report from a contactable physician (patient), this physician reported information for both mother and fetus/baby. This is the maternal report. Only this case is serious.  A 35-year-old female patient (not pregnant at the time of vaccination) received second dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE) intramuscular into left arm on 05Feb2021 09:00 at single dose for COVID-19 immunization in workplace clinic. Medical history included hx of passing out remote in distant past. No allergies to medications, food, or other products. concomitant medications were none (no other medications the patient received within 2 weeks of vaccination). The patient did not receive any other vaccines within 4 weeks prior to the COVID vaccine. patient previously took the first dose of BNT162B2 on unspecified date at single dose for covid-19 immunization. About 17 hours after vaccine, at 3am (06Feb2021 03:00), while up feeding her infant and sitting in a chair in the dark, she started to feel very strange, kind of like she was going to pass out (hx of passing out remote in distant past). No hearing or vision loss, just a general strange and uncomfortable feeling. Tried to call for help. Lost consciousness for a few seconds and had deep dreaming, then awoke feeling poorly. Set child back to bed, went to bed myself, had shaking chills for maybe 30 minutes following. No sweats, no normal symptoms related to vasovagal syncope. Just a general uncomfortable strange sensation as the prodrome. Prior to vaccination, was the patient was not diagnosed with COVID-19. Since the vaccination, the patient has not been tested for COVID-19. No treatment received for the events. Patient was recovered from the events on unspecified date. It was reported as non-serious report. Seriousness criteria results in death, life threatening, caused/prolonged hospitalization, disabling/incapacitating and congenital anomaly/birth defect were all no.  Information on the lot/batch number has been requested.; Sender's Comments: Based on the available information, the Company considers the reported event loss of consciousness recurrence is unrelated to BNT162B2 vaccine but more likely an inter-current medical condition in this subject with medical history of passing out remote in distant past. 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-2021240721 mother/baby case