Second Moderna shot gave her a mini heart attack; fluid around her heart; maternal exposure during pregnancy; This spontaneous retrospective pregnancy case was reported by a patient and describes the occurrence of MYOCARDIAL INFARCTION (Second Moderna shot gave her a mini heart attack) and PERICARDIAL EFFUSION (fluid around her heart) in a female patient of an unknown age who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.    On an unknown date, the patient received second dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. Last menstrual period and estimated date of delivery were not provided. On an unknown date, the patient experienced MYOCARDIAL INFARCTION (Second Moderna shot gave her a mini heart attack) (seriousness criterion medically significant), PERICARDIAL EFFUSION (fluid around her heart) (seriousness criterion medically significant) and MATERNAL EXPOSURE DURING PREGNANCY (maternal exposure during pregnancy). The delivery occurred on an unknown date, which was reported as Unknown. For neonate 1, The outcome was reported as Unknown. At the time of the report, MYOCARDIAL INFARCTION (Second Moderna shot gave her a mini heart attack) and PERICARDIAL EFFUSION (fluid around her heart) outcome was unknown and MATERNAL EXPOSURE DURING PREGNANCY (maternal exposure during pregnancy) had resolved.            Patient was working in Healthcare and she just had a baby.  Relevant concomitant medications were not reported. Treatment information was not provided.  Patient received second dose of Moderna COVID-19 vaccine and experienced a mini heart attack from fluid around the heart. The patient got the booster as well. It was reported that patient went with Pfizer and there was no issue.  Company Comment: This is a spontaneous case concerning a female patient (unknown age) with no reported medical history, who experienced the unexpected serious (medically significant) AESI of myocardial infarction and unexpected serious medically significant event of pericardial effusion. This was a case of maternal exposure during pregnancy (reportedly, the patient just had a baby and wanted her kid to have antibodies, in case the family "brought it in while visiting"). The events occurred after the administration of the second dose of mRNA-1273 vaccine, latency is unknown. The patient reported " a mini heart attack from fluid around the heart" after the second dose, however, no further information was disclosed. The patient received Pfizer vaccine after the second dose of mRNA-1273, but reported "no issues" after that. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a female patient (unknown age) with no reported medical history, who experienced the unexpected serious (medically significant) AESI of myocardial infarction and unexpected serious medically significant event of pericardial effusion. This was a case of maternal exposure during pregnancy (reportedly, the patient just had a baby and wanted her kid to have antibodies, in case the family "brought it in while visiting"). The events occurred after the administration of the second dose of mRNA-1273 vaccine, latency is unknown. The patient reported " a mini heart attack from fluid around the heart" after the second dose, however, no further information was disclosed. The patient received Pfizer vaccine after the second dose of mRNA-1273, but reported "no issues" after that. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.