Fever; Headache; Chills; Feeling like a heavy weight on her body; Back pain; This is a spontaneous report from a contactable nurse, the patient.  A 34-year-old female patient received the second dose of BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE; Lot Number: EZ3247), via an unspecified route of administration in the left arm on 23Jan2021 at 15:20 (at the age of 34-years-old) as a single dose for COVID-19 immunization.  Medical history included gestational diabetes (first pregnancy) from an unknown date to an unknown date and two pregnancies on unknown dates. Concomitant medications included unspecified post-natal multivitamins and paracetamol (TYLENOL; Lot Number: SBA22; Expiration Date: Jan2023) taken before getting the vaccine on 23Jan2021 to prevent soreness. The patient previously received the first dose of BNT162B2 on 03Jan2021 (at the age of 34-years-old; Lot Number: EL0142) in the left arm for COVID-19 immunization. The patient did not receive any other vaccines within four weeks prior to the vaccination (except the first dose). On 24Jan2021 at 04:00, the patient experienced chills and had a feeling like a heavy weight on her body. On 24Jan2021 at 07:00, the patient had a fever and headache. On 24Jan2021, she also had back pain. The clinical course was as follows: On 23Jan2021, the patient took paracetamol before getting the vaccine as she heard one can feel sore after getting it. The patient received the second dose on 23Jan2021 at 15:20. The patient was okay after she got the vaccine. However, early the next morning (24Jan2021), she had shivering without any fever (later referred to as chills). The chills were something she never experienced in her life. It was like she was in the cold. She could not move, it was that bad. She felt a heavy weight on her whole body. She could not get out of bed.  A few hours later at 07:00, she checked her temperature and it was 102.5 degrees Fahrenheit. She took paracetamol. The headache started with the fever around 07:00. She stated she kept taking paracetamol. She did try to stop using paracetamol, but without it, the headache was still there. The back pain was also severe on 25Jan2021. The chills recovered on 25Jan2021 and the fever was recovered on 26Jan2021. The clinical outcomes of the headache and felt like a heavy weight on the body were unknown; while that of the back pain was not recovered. The events of chills, fever, headache, and back pain were reported as serious by the patient (nurse) for being medically significant. The patient (nurse) assessed the events of chills, fever, headache, back pain, and felt like a heavy weight on her body were related to the vaccine.; Sender's Comments: Based on a compatible temporal association and known BNT162B2 vaccine safety profile causality between reported events and BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE) cannot be excluded. 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.