vertigo;   This is a report from an interventional study sponsored by BioNTech, managed and reported by Pfizer on the sponsor's behalf. The subject was in open-label phase of the study when the event occurred. A 72-year-old female subject received first and second dose of blinded therapy vaccine (BNT162; PLACEBO) on 31Aug2020 and 21Sep2020 respectively. She then received third dose of study vaccine (BNT162B2) on 13Jan2021 at 15:48 and fourth dose of study vaccine (BNT162B2) on 02Feb2021 at 11:50, both intramuscularly on left deltoid as single doses, all for COVID-19 immunization. Medical history included insomnia from 2010 and ongoing, sleep apnea from 2010 and ongoing, left knee osteoarthritis from 2014 to 2017 (with left total knee arthroplasty), osteoporosis from 2016 and ongoing and basal cell carcinoma on nose in 2018. No concomitant vaccines or prior vaccinations (within 4 weeks) were received. Family medical history relevant to the adverse event (AE) was unknown. Ongoing concomitant medications included estradiol (ESTROGEL) as hormone replacement from 2019, denosumab (PROLIA) for osteoporosis from 2017, zolpidem tartrate (AMBIEN) for insomnia from 2010; and ascorbic acid (VITAMIN C), zinc, vitamin B6, quercetin and glucosamine, all as health supplement from Mar2020.  On 03Feb2021, the subject experienced vertigo with serious criteria of medically significant and hospitalization. The event required a visit to emergency room. The clinical course was as follows: Around midnight on 03Feb2021, the subject did not feel well with severe chills. She got up out of bed and went to the bathroom. She experienced vertigo, fell and hit her head. She was found bleeding by her husband who called the ambulance. She was taken to the hospital and had 7 stitches placed. She was still in the hospital at the time of the report. The action taken in response to the event for study vaccine BNT162B2 was not applicable. The outcome of event was not recovered.  The investigator considered there was a reasonable possibility that the event vertigo was related to the study vaccine but not related to concomitant drugs or clinical trial procedure.; Sender's Comments: The event "Vertigo" is unlisted in the Single Reference Safety Document (SRSD) of the Investigational Product therapy vaccine (BNT162B2).  The information provided is very limited and mainly anecdotal. Results of the diagnostic workup during hospitalization are not available. The company considers there is not a reasonable possibility that the event, vertigo, is related to vaccine administration based on the latency, the circumstances and a possible role of concomitant medication zolpidem.  Pfizer's safety database was reviewed for cases reporting PF-07302048 or blinded therapy through 15-JAN-2021 for adverse events encoding to MedDRA (v.23.1J) Preferred Term(s) of Vertigo. Review of the database for the PT Vertigo had the following results: 2 serious clinical trial cases (0 of which were attributed to therapy) and 109 non clinical trial cases.  The impacts of this report on the benefit/risk profile of the Pfizer product and on the conduct of the study 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 Committee and Investigators, as appropriate.