started frailing with shivers and shaking uncontrollably on and off; diarrhea; aching; chilling; I was so weak and I slept so much; WBC increased; Mean corpuscular hemoglobin low; Platelet count high; Monocyte count high; Neutrophil count high; Flu symptoms; stomach flu symptoms; extreme dry heaves; she thought was the  flu; Vomiting; nausea; had a feeling of shivers that was not normal; headaches; had a feeling of shivers that was not normal; This is a spontaneous report from a contactable other HCP (patient herself). A 72-years-old female patient received BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: solution for injection, batch/lot number: unknown, expiry date: unknown) via unknown route of administration, in right arm on 06Mar2021 08:00 (age at vaccination: 72) as DOSE 2, SINGLE for Covid-19 immunisation. Patient medical history included ongoing high blood pressure ever since she was overweight, clarifying she was diagnosed about 30 years ago. Her high blood pressure was controlled by medication. Patient previously received first dose of vaccine (Lot Number: EN6200), via unknown route of administration, in right arm, on 13Feb2021, as DOSE 1, SINGLE for Covid-19 immunisation. After vaccination, she had 4 events that lasted over a 2-month period after receiving 2nd Pfizer vaccine dose.  It all started the second week of April. She ended up with what she thought was the flu. The 1st event was extreme dry heaves, diarrhea, vomiting, aching and chilling, no fever. She had the flu-like symptoms for several days but didn't have a temperature. She said it was not normal for her to not have a temperature when she had the flu. She eventually got better. It was reported she had recently changed doctors because her primary care doctor had retired. Her new doctor had ordered blood work on 01Apr2021, and that blood work was fine. About a week and a half after her doctor's appointment, her son called her to tell her he had come down with the stomach flu. After she spoke to her son over the phone, she had stomach flu symptoms, clarified as nausea and vomiting. A couple weeks later she was out eating, and when she got home, had 30 mins of very mild shivers that was not normal. She put a quilt, blanket, and sheet over herself, and was shaking so hard for a couple days. She said she didn't know what it was that caused the shivers. Her shivers happened, again, a week and a half later. She saw her doctor, and her doctor told her the shivers were a reaction to the COVID-19 Vaccine. Her doctor told her he had seen the same thing (shivers) happen in a few of his other patients. Patient stated she went to her Dr and he prescribed dexamethasone. She said she took the Dexamethasone 2.5mg for 5 days, and she did not have the Dexamethasone 2.5mg NDC, Lot, and Expiry Date. She said she had the normal Dexamethasone side effect of insomnia, but the Dexamethasone helped her immensely. She was so weak and slept so much. It was reported she had about 30 minutes of slight shivers a week and a half after she took the Dexamethasone 2.5mg. She said she hoped her doctor's diagnosis was correct. She said she hadn't had anymore shivers since then. She took it in June and all the shaking went away. She had taken Tylenol for headaches that she experienced occasionally during that time but did not know if the headaches were related to the COVID-19 Vaccine. Patient heard Pfizer was recommending a COVID-19 Vaccine booster shot, if the FDA approved. She wondered if anyone else reported anything like she experienced. She said she didn't know what else would have caused her symptoms. Caller was advised she would be transferred to Pfizer Medical Information for further assistance with her questions. She went to her first doctor appointment on 01Apr2021 for a new patient visit, clarifying she was not sick at the time. She had bloodwork done on 08Apr2021, and her bloodwork was OK, with no problems whatsoever. She donated blood through a blood drive on 21Apr2021. On 07Jun2021, she had bloodwork done, again, after she made a doctor's appointment for her shivers. Her bloodwork was not normal, clarifying her WBCs were elevated (15.5 x 1000), her Mean Corpuscular Hemoglobin Cone was low at 31.5 (reference range: 32.0-35.0), her Platelet Count was high at 424 x 1000 (reference range: 140-350), her Monocyte Count was high at 1.22 x 1000, and her Neutrophil Count was high at 12.7 x 1000. She was normally a very healthy person and was current on her flu and pneumonia vaccines. She was getting her second shingles shot, clarifying she had a prior shingles vaccine a long time ago that was 50/50 (effective). She said she was going to go to Walmart today to get her first of two Shingrix Vaccine doses. She said she wanted to get the second Shingrix dose before her flu shot later this year. Patient was concerned about the 3rd shot of Covid-vaccine and having the same symptoms. She was replied that as part of Pfizer and BioNTech continued efforts to stay ahead of the virus causing COVID-19 and circulating mutations, the companies provided an update on booster dosing on 09Jul2021. The use of a 3rd or booster dose is not recommended or authorized, and Pfizer does not suggest the use of the vaccine in any manner other than as described in the authorized EUA Prescribing Information (name) authorized product monograph. Initial data from the ongoing study of booster doses demonstrated a consistent tolerability profile and high neutralization titers against the wild-type virus (the naturally occurring non-mutated virus) and the Beta variant. It was thought that the effects seen against the Beta variant may also be seen in the Delta variant. They were doing studies to confirm this. They expect to publish the data soon in a peer-reviewed journal and submit to regulatory authorities in the coming weeks. Note to frontline: This FAQ should only be used if an HCP or non-HCP specifically asks about the Pfizer statement on booster doses. For HCPs with general inquiries about booster doses, please refer to the SRD titled -Administration of More Than a 2-Dose Series (Booster Dose). The outcome of event for extreme dry heaves, flu, shivers, feeling abnormal was recovered on an unspecified date, for vomiting it was recovering, and the rest unknown.   Communication: The caller was provided with phone number of #, option 3, and hours of operation of Monday through Friday 9AM to 5PM, prior to warm transfer; Sender's Comments: As there is limited information in the case provided, the causal association between the events (Shaking, Retching, flu, vomiting .nausea, chills, viral GI ,feeling abnormal) and the suspect drug cannot 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.