hypokalemia (2.9 mmol/L); hypocalcemia (6.4 mg/dL); puffy eyes; respiratory symptoms; possibly stridor; This is a spontaneous report from a contactable physician. A 19-year-old female patient received bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, solution for injection), dose 1 via an unspecified route of administration on 19May2021 (Batch/Lot number was not reported) as 1ST DOSE, SINGLE DOSE for covid-19 immunisation.  Medical history included food allergy, anaphylactic reaction. The patient's concomitant medications were not reported. The patient woke up the next morning on 20May2021 with puffy eyes and respiratory symptoms (possibly stridor) and self-administered epinephrine, then was taken to the nearest ED where she received additional epi and albuterol. Those symptoms eventually subsided, but what triggered the study stop was her lab findings consisting of hypokalemia (2.9 mmol/L) and hypocalcemia (6.4 mg/dL). In the AE grading scale that the study is using (the FDA's scale used in vaccination studies), these values are considered Grade 4 As such, we met the study stopping rule of a single Grade 4 event and since they were detected one day after vaccination, the site PI indicated that they could be "possibly related" to the vaccine. These abnormalities were promptly corrected and the participant is doing OK, based on the most recent update. There is no report that the reporter could identify that these electrolyte abnormalities are vaccine related and I am contacting you to confirm that this is, indeed, the case. We believe other explanations should be considered (e.g. epinephrine plus beta agonist administration can lead to both hypokalemia and hypocalcemia through beta2 effects; alternatively, or in addition, hyperventilation could result in respiratory alkalosis that has similar effects). The patient underwent lab tests and procedures which included blood calcium: 6.4 mg/dl on an unspecified date Hypocalcemia , blood potassium: 2.9 mmol/l on an unspecified date Hypokalemia.  Therapeutic measures were taken as a result of puffy eyes, respiratory symptoms, possibly stridor. The outcome of the events was unknown.   Information regarding lot/batch number has been requested.; Sender's Comments: Based on the available information and known product profile, the causal relationship between the reported puffy eyes and respiratory symptoms (possibly stridor) and the use of bnt162b2 is possible. Considering that these events likely occurred under the context of an allergic reaction based on the temporal association and the positive response to epinephrine and albuterol. The patient also has a history of food allergy, anaphylactic reaction which place the patient at risk.  As for the events , hypokalemia and hypocalcemia, agree with the reporter that the use of the beta 2 agonist , as well as the respiratory alkalosis explain the occurrence of these events.  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.