Acute worsening of clinical presentation in complex regional pain syndrome (CRPS); This literature-non-study case was reported in a literature article and describes the occurrence of COMPLEX REGIONAL PAIN SYNDROME (Acute worsening of clinical presentation in complex regional pain syndrome (CRPS)) in a 21-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.   LITERATURE REFERENCE:     Concurrent medical conditions included Complex regional pain syndrome Type I.    On an unknown date, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced COMPLEX REGIONAL PAIN SYNDROME (Acute worsening of clinical presentation in complex regional pain syndrome (CRPS)) (seriousness criterion medically significant). At the time of the report, COMPLEX REGIONAL PAIN SYNDROME (Acute worsening of clinical presentation in complex regional pain syndrome (CRPS)) outcome was unknown. Related      The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered COMPLEX REGIONAL PAIN SYNDROME (Acute worsening of clinical presentation in complex regional pain syndrome (CRPS)) to be related.    Patient reported severe exacerbation of bilateral lower extremity burning pain within 24 h after the first dose.  The acute clinical worsening after mRNA-based COVID-19 vaccination was transient and effectively managed with adjustment of individualized therapy in the patient.  Company Comment: This literature non-study case concerns a 21 year old male  patient with relevant medical history of Complex regional  pain syndrome type I , who experienced Serious ( medically significant ) , unexpected event of Complex regional pain syndrome ( Acute worsening of clinical presentation in complex regional pain syndrome)  which occurred on an unknown date post vaccination with the 1st dose of mRNA-1273 vaccine. It was reported that the event occurred within 24 hours after  vaccination with the 1st dose of the mRNA-1273 vaccine.  The acute clinical worsening after mRNA-based COVID-19 vaccination was transient and effectively managed with adjustment of individualized therapy. The details surrounding this event were not reported since the full text of this literature for review is not available.  The outcome of the event was reported as unknown. The benefit -risk relationship of mRNA -1273 ( Moderna Covid 19 Vaccine) is not affected by this report. The reviewer has limited information regarding this case as mentioned since the full text was not available at the time of the medical review.   This case was linked to MOD-2022-511679 (Patient Link).; Sender's Comments: This literature non-study case concerns a 21 year old male  patient with relevant medical history of Complex regional  pain syndrome type I , who experienced Serious ( medically significant ) , unexpected event of Complex regional pain syndrome ( Acute worsening of clinical presentation in complex regional pain syndrome)  which occurred on an unknown date post vaccination with the 1st dose of mRNA-1273 vaccine. It was reported that the event occurred within 24 hours after  vaccination with the 1st dose of the mRNA-1273 vaccine.  The acute clinical worsening after mRNA-based COVID-19 vaccination was transient and effectively managed with adjustment of individualized therapy. The details surrounding this event were not reported since the full text of this literature for review is not available.  The outcome of the event was reported as unknown. The benefit -risk relationship of mRNA -1273 ( Moderna Covid 19 Vaccine) is not affected by this report. The reviewer has limited information regarding this case as mentioned since the full text was not available at the time of the medical review.