autoimmune hemolytic anemia, fatigue; This spontaneous case was reported by a patient and describes the occurrence of AUTOIMMUNE HAEMOLYTIC ANAEMIA (autoimmune hemolytic anemia, fatigue) in a 69-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 041L20A) for COVID-19 vaccination.     The patient's past medical history included Chronic lymphocytic leukemia (diagnosed in 2015 but it was Stage 0.) in 2015.    On 01-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced AUTOIMMUNE HAEMOLYTIC ANAEMIA (autoimmune hemolytic anemia, fatigue) (seriousness criterion medically significant). The patient was treated with PREDNISONE at an unspecified dose and frequency and ACALABRUTINIB in October 2021 at a dose of 200 mg once a day. At the time of the report, AUTOIMMUNE HAEMOLYTIC ANAEMIA (autoimmune hemolytic anemia, fatigue) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In February 2021, Haemoglobin decreased: result not provided.     mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) dosing remained unchanged.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   The patient reported an unusual reaction developed after getting the 1st dose of the Moderna Covid-19 vaccine 1st week of Feb2021. A week after the patient administered the 1st dose of the vaccine the patient started to experienced fatigue and ended up going to the hospital because the hemoglobin level dropped significantly. Blood transfusion was done and the patient was given a Prednisone course. When prednisone was stopped hemoglobin level went back to low so another prednisone course was given but hemoglobin still dropped. Another blood transfusion was done. In Oct2021, the patient was started Acalabrutinib (Calquence) 200 mg once a day. The patient was diagnosed was having autoimmune hemolytic anemia.  No concomitant medication information provided  Company comment- This spontaneous case concerns a 69-year-old male patient with relevant medical history of Chronic lymphocytic anemia, who experienced unexpected, serious (medically significant) event of Autoimmune haemolytic anemia, which occurred approximately a week after vaccination with a first dose of mRNA-1273. The patient reported that a week after his vaccination, he noted fatigue. He sought consult in the hospital wherein he was noted to have a low hemoglobin. Blood transfusion was done, and he was given a course of prednisone. When the course of prednisone was stopped, the hemoglobin decreased again and another course of prednisone was again given but still the hemoglobin dropped. Blood transfusion was again done. 8 months after, he was diagnosed with autoimmune haemolytic anemia and was started on Acalabrutinib (Calquence) 200 mg once a day. The outcome of the events was reported as not resolved. The relevant medical history of Chronic lymphocytic anemia is a risk factor for the event. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 29-Aug-2022: Significant live follow up received on 29-AUG-2022, reporters details (physician), suspect product details (start date, lot number) was updated.; Sender's Comments: This spontaneous case concerns a 69-year-old male patient with relevant medical history of Chronic lymphocytic anemia, who experienced unexpected, serious (medically significant) event of Autoimmune haemolytic anemia, which occurred approximately a week after vaccination with a first dose of mRNA-1273. The patient reported that a week after his vaccination, he noted fatigue. He sought consult in the hospital wherein he was noted to have a low hemoglobin. Blood transfusion was done, and he was given a course of prednisone. When the course of prednisone was stopped, the hemoglobin decreased again and another course of prednisone was again given but still the hemoglobin dropped. Blood transfusion was again done. 8 months after, he was diagnosed with autoimmune haemolytic anemia and was started on Acalabrutinib (Calquence) 200 mg once a day. The outcome of the events was reported as not resolved. The relevant medical history of Chronic lymphocytic anemia is a risk factor for the event. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.