acute myocarditis after vaccination against SARS-CoV-2; Blood analytics showed myocardial infarction markers elevation; persistent fever of 38°C or higher; manifested intermittent and interscapular thoracic pain; This is a literature report entitled Acute myocarditis after administration of the BNT162b2 vaccine against COVID-19; published in 2021.  The adverse reactions to vaccines are usually ordinary, but cases of myopericarditis have been reported following their application. On the other hand, different cases of myopericarditis related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been recently published. A case has been described of a 39-year-old male patient, medical doctor, with personal record of bronchial asthma, autoimmune hypothyroidism, chronic atrophic gastritis, isolated episode of atrial fibrillation and spontaneous pneumothorax recurrence with left apical segmentectomy. Last months, he had various screenings through PCR and serology for SARS-CoV-2 infection, all of them negative. Patient has had given informed consent for writing and publishing of the clinical case. Following the vaccine series against COVID- 19, he was administered with the first dose of BNT162b2 vaccine, without relevant adverse reactions. Past the 6 hours of vaccine second dose administration, 21 days after first dose, he initiated with persistent fever of 38°C or higher, that was treated with antipyretic medication. Subsequently he manifested intermittent and interscapular thoracic pain, that persisted several hours without relief from conventional analgesia, reason to reach out emergency department. At his arrival, electrocardiogram showed sinus tachycardia of 130bpm with narrow QRS and diffuse ST elevation. Thoracic x-ray did not show relevant findings. Blood analytics showed myocardial infarction markers elevation, with a first outcome of high sensitive troponin T (hs-TnT) of 139 ng/l. PCR for SARS-CoV-2 was performed and resulted negative. Given the medical data, electrocardiographic alterations and analytical parameters, a transthoracic echocardiogram was run, that showed good biventricular function, without segmentary alterations of contractility, significant valvulopathies or pericardial effusion. Furthermore, an acute aort ic syndrome was ruled out through throracic computed tomography angiography (CT-angio); coronary study could not be performed through this technique due to impossibility of optimal heart rate control. With diagnostic suspicion of acute myocarditis, anti-inflammatory treatment was restored, and patient remained asymptomatic. However, patient's transfer to a reference third level hospital was decided to continue the study. At presentation, patient arrived with a hemodynamic stability condition and asymptomat ic, with punctual episodes of thoracic pain. Consecutive electrocardiograms showed a partial rectification of ST changes, with negativization of T wave in precordial derivations. Enzymatic peak of hs-TnT was 854 ng/l. First 48 hours a coronary CTangio was performed that ruled out coronary disease and a magnetic cardiac resonance that showed edema in T2-STIR weighted sequences and subepicardial enhancement in the distal medial lateral region, compatible with acute myocarditis. Study was completed with viral serology and screening through polymerase chain reaction (PCR) of prime cardiotropic viruses plasma, as well for SARS-CoV-2 in a new oropharyngeal sample, with negative result. It was proven by unspecific positive IgM serology study, positive IgG (spike) and negative IgG (nucleocapsid), pattern that shows immunization after SARS-CoV-2 vaccination, since spike protein is the one coded by mRNA administered with the vaccine. Due to low risk profile and promising evolution, an endomyocardial biopsy was not proposed. At last, the patient presented beneficial clinical response, with full recovery of the symptoms, 6 days after admission he was discharged. Given the obvious temporary relation between the vaccination process and clinical picture development, and the exclusion of other acute cardiological conditions, this acute myocarditis picture is being proposed as an adverse reaction related to BNT162b2 vaccine. In this case, a patient with personal record of bronchial asthma, autoimmune hypothyroidism and chronic atrophic gastritis, it is stated the hypothesis that the vaccine could have caused the autoimmune reaction manifested as acute myocarditis. In the presented case, the definitive etiological diagnosis, equally to several pictures of acute myocarditis, is difficult to establish. Because of the clear temporary relation and the matching serological pattern with immunity after vaccination, as well after acute infection ruling out, it seems reasonable to link the clinical picture developed by this patient with an adverse reaction to BNT162b2 vaccine against COVID-19. In conclusion, a case of acute myocarditis after vaccination against SARS-CoV-2 is presented in which has been outlined that is the first case published as adverse reaction to this vaccine.  Information about lot/batch number cannot be obtained. No further information is expected.; Sender's Comments: Based on chronological connection to the vaccine, causality between reported events and BNT162B2 vaccine cannot be completely excluded. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified.