This is a literature report for the following literature source: Acute worsening of clinical presentation in CRPS after SARS-CoV-2 (COVID-19) vaccination: A case series, Pain Management, 2022; Vol 12(3); PGS: 249-254; DOI: 10.2217/pmt-2021-0089. A 23-year-old female patient received BNT162b2 (BNT162B2), as dose 1, single (Batch/Lot number: unknown) for Covid-19 immunisation. The patient's relevant medical history included: "CRPS type I" (ongoing); "lumbar sympathetic blocks" (unspecified if ongoing), notes: for 1 year with over 90% improvement of the right ankle and foot pain and symptoms; "physical therapy" (unspecified if ongoing), notes: for 1 year with over 90% improvement of the right ankle and foot pain and symptoms. Concomitant medication(s) included: ACETAMINOPHEN taken for complex regional pain syndrome. The following information was reported: CONDITION AGGRAVATED (hospitalization, medically significant), 3 hrs. after the suspect product(s) administration, outcome "recovering", described as "severe exacerbation of the burning pain in the right foot extending proximally to the entire"; MUSCLE SPASMS (hospitalization), 3 hrs. after the suspect product(s) administration, outcome "recovering"; TEMPERATURE DIFFERENCE OF EXTREMITIES (hospitalization), 3 hrs. after the suspect product(s) administration, outcome "recovering", described as "temperature changes in the right leg, ankle and foot"; PERIPHERAL SWELLING (hospitalization), 3 hrs. after the suspect product(s) administration, outcome "recovering", described as "Swelling"; SKIN DISCOLOURATION (hospitalization), 3 hrs. after the suspect product(s) administration, outcome "recovering", described as "color changes"; HYPERAESTHESIA (hospitalization), 3 hrs. after the suspect product(s) administration, outcome "recovering", described as "sensitivity to touch". The patient was hospitalized for condition aggravated, temperature difference of extremities, peripheral swelling, skin discolouration, hyperaesthesia (hospitalization duration: 6 day(s)). The events "severe exacerbation of the burning pain in the right foot extending proximally to the entire", "muscle spasms", "temperature changes in the right leg, ankle and foot", "swelling", "color changes" and "sensitivity to touch" required emergency room visit. Therapeutic measures were taken as a result of condition aggravated, muscle spasms, temperature difference of extremities, peripheral swelling, skin discolouration, hyperaesthesia. No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected. Sender's Comments: Based on the information currently available, The casual association between the reported event and suspected vaccine BNT162B2 cannot be completely 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.