AUTOMIMMUNIE HEMOLYTIC ANEMIA; ACUTE KIDNEY INJURY; This 33-year-old, male subject was participating in "A Phase 3b, Open-Label, Safety and Immunogenicity Study of SARS-CoV-2 mRNA-1273 Vaccine in Adult Solid Organ Transplant Recipients and Healthy Controls (mRNA-1273-P304)" and experienced the serious adverse event of special interest (AESI) of acute kidney injury and serious adverse event of autoimmune hemolytic anemia.  The subject's medical history, as provided by the investigator, included kidney transplant, induction therapy with basiliximab, Alport's syndrome, hemolytic anemia, hyperlipidemia, hypertension, and gout (in left great toe). Concomitant medications reported included amlodipine, prednisone, tacrolimus, and allopurinol.   Prior to event onset, the subject received intramuscular mRNA-1273 (Dose 2) for SARS-CoV-2 vaccination on 28 Sep 2021, approximately 4 months before onset of the events.  On an unspecified date, the subject's hemoglobin was 5.9 g/dL (13.5-16) and hematocrit level was 17.7 percent (%) (37-47). He was directed by the principal investigator and his nephrologist to go to the emergency department.  On 27 Jan 2022, the subject experienced acute kidney injury and autoimmune hemolytic anemia and was admitted to the hospital. The subject tested positive for SARS-CoV-2 upon admission but was not symptomatic. Subject's serum creatinine was 2.16 g/dL when admitted and increased to 2.25 g/dL later on that day (increase of 0.09 g/dl).  On 29 Jan 2022, serum creatinine was 2.35 g/dL (a difference of 0.19 g/dL from initial value on the 27th). Thus, the subject's creatinine increased more than 0.03 g/dL within 48 hours.  As of 31 Jan 2022, the subject was still hospitalized. There were no plans or expected date of discharge as the subject's hemoglobin was only 5.8 g/dL. Treatment information was not provided.  No action was taken with the study drug in response to the events.   The events, acute kidney injury and autoimmune hemolytic anemia, were reported as not resolved.   The investigator assessed the event, acute kidney injury, as not related to study drug and not related to study procedure. The investigator assessed the event, autoimmune hemolytic anemia, as related to study drug and not related to study procedure. The investigator replied that it was possible that as the subject's particular type of anemia was autoimmune, it may have been triggered by the vaccine back in Oct 2021.  Follow-up received on 03 Feb 2022 included downgrades of SAE SARS-CoV-2 (coronavirus disease 2019) to a non-serious adverse event, removal of AESI of autoimmune hemolytic anemia, updates to study drug causality assessments, severity assessment for autoimmune hemolytic anemia, and laboratory results for acute kidney injury.  Company Comment: This case concerns a 33-year-old, male subject with medical history of kidney transplant, induction therapy with basiliximab, Alport's syndrome, hemolytic anemia, hyperlipidemia, hypertension, and gout (in left great toe), who experienced  the serious adverse event of special interest (AESI) of acute kidney injury and serious adverse event of autoimmune hemolytic anemia. The events occurred 4 months 26 days after the first dose of IP and 4 months after the second and last dose. No action was taken with the study drug in response to the events. The events were reported as not resolved. The investigator´s assessment of the events was not provided. Subject started with tacrolimus therapy on 04-NOV-2019. As per the investigator, it was possible that as the subject's particular type of anemia was autoimmune, it may have been triggered by the vaccine back in Oct 2021. The Sponsor assessed the events as not related to the vaccine, due to the very limited information provided (such as hemotology panel and antibodies at baseline) and the long latency to onset. Recent COVID-19 infection could be a contributory factor for the hemolytic anemia. The acute kidney injury´s etiology is unclear based on the subject history of renal transplant in 2017.; Reporter's Comments: Company Comment: This case concerns a 33-year-old, male subject with medical history of kidney transplant, induction therapy with basiliximab, Alport's syndrome, hemolytic anemia, hyperlipidemia, hypertension, and gout (in left great toe), who experienced  the serious adverse event of special interest (AESI) of acute kidney injury and serious adverse event of autoimmune hemolytic anemia. The events occurred 4 months 26 days after the first dose of IP and 4 months after the second and last dose. No action was taken with the study drug in response to the events. The events were reported as not resolved. The investigator´s assessment of the events was not provided. Subject started with tacrolimus therapy on 04-NOV-2019. As per the investigator, it was possible that as the subject's particular type of anemia was autoimmune, it may have been triggered by the vaccine back in Oct 2021. The Sponsor assessed the events as not related to the vaccine, due to the very limited information provided (such as hemotology panel and antibodies at baseline) and the long latency to onset. Recent COVID-19 infection could be a contributory factor for the hemolytic anemia. The acute kidney injury´s etiology is unclear based on the subject history of renal transplant in 2017. Further information was requested.