her hemoglobin levels dropped from 10 to 6; Ultrasound confirmed malignancy in breast/breast tissue has some abnormality present; abnormal mammogram that showed abnormal lymph node enlargement; This spontaneous case was reported by a consumer (subsequently medically confirmed) and describes the occurrence of HAEMOGLOBIN DECREASED (her hemoglobin levels dropped from 10 to 6) and BREAST CANCER FEMALE (Ultrasound confirmed malignancy in breast/breast tissue has some abnormality present) in a 79-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Glaucoma and Autoimmune hemolytic anemia (was reportedly stable until she received the Moderna COVID-19 vaccine).    In January 2021, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In February 2021, the patient experienced BREAST CANCER FEMALE (Ultrasound confirmed malignancy in breast/breast tissue has some abnormality present) (seriousness criterion medically significant) and LYMPHADENOPATHY (abnormal mammogram that showed abnormal lymph node enlargement). In September 2021, the patient experienced HAEMOGLOBIN DECREASED (her hemoglobin levels dropped from 10 to 6) (seriousness criterion medically significant). In August 2021, BREAST CANCER FEMALE (Ultrasound confirmed malignancy in breast/breast tissue has some abnormality present) and LYMPHADENOPATHY (abnormal mammogram that showed abnormal lymph node enlargement) had resolved. At the time of the report, HAEMOGLOBIN DECREASED (her hemoglobin levels dropped from 10 to 6) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In February 2021, Mammogram: abnormal (abnormal) breast tissue has some abnormality present, abnormal lymph node enlargement.. In August 2021, Mammogram: normal (normal) mammogram came back with normal results. In September 2021, Haemoglobin: 10 (Low) hemoglobin levels dropped from 10 to 6 and 6 (Low) hemoglobin levels dropped from 10 to 6. On an unknown date, Haemoglobin: decreased (Low) decreased. On an unknown date, Intraocular pressure test: high (High) intraocular pressure has doubled from March to October. On an unknown date, Ultrasound scan: abnormal (abnormal) confirmed the presence of a malignancy.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.       No concomitant medication were reported.  Treatment included transfusion for low hemoglobin levels. The patient reported that she received the Moderna COVID-19 vaccine and had serious adverse effect. In Feb 2021 when she was scheduled for a routine mammogram patient reports she never had abnormal results but in this mammogram she was told by a nurse that her breast tissue had some abnormality present, abnormal lymph node enlargement. There was an ultrasound done which confirmed the presence of a malignancy and there was a follow up in Aug 2021 where the patient reports the mammogram came back with normal results. The patient experienced drop in levels of hemoglobin when the patient had blood work done. In Sep 2021 her hemoglobin levels dropped from 10 to 6, she had to go in for an infusion. She was a doubling in eye pressure. The patient reported that after receiving the Moderna COVID-19 vaccine her intraocular pressure increased.  This case concerns a 79-year-old, female patient with a history of Autoimmune hemolytic anemia, who experienced the unexpected serious events of breast cancer female and haemoglobin decreased. The event breast cancer female occurred approximately during the following month after the first dose of Spikevax and the event haemoglobin decreased, after eight months of the first dose of Spikevax. The event breast cancer female recovered, although no specific treatment is described, and the diagnosis was performed with an ultrasound study (no histological confirmation was reported). The rechallenge was unknown since no information about the second dose was available. The patient´s age could be a confounder for breast cancer female and medical history of Autoimmune hemolytic anemia remains a confounder for haemoglobin decreased. The benefit-risk relationship of Spikevax is not affected by this report.; Sender's Comments: This case concerns a 79-year-old, female patient with a history of Autoimmune hemolytic anemia, who experienced the unexpected serious events of breast cancer female and haemoglobin decreased. The event breast cancer female occurred approximately during the following month after the first dose of Spikevax and the event haemoglobin decreased, after eight months of the first dose of Spikevax. The event breast cancer female recovered, although no specific treatment is described, and the diagnosis was performed with an ultrasound study (no histological confirmation was reported). The rechallenge was unknown since no information about the second dose was available. The patient´s age could be a confounder for breast cancer female and medical history of Autoimmune hemolytic anemia remains a confounder for haemoglobin decreased. The benefit-risk relationship of Spikevax is not affected by this report.