Thyroiditis after mRNA Vaccination for COVID-19; This is a literature report for the following literature source(s):   A 33-year-old male patient received BNT162b2 (BNT162B2), as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "Anxiety disorder" (unspecified if ongoing); "Persistent palpitation" (unspecified if ongoing), notes: two week history; "heat intolerance" (unspecified if ongoing), notes: two week history; "weight loss" (unspecified if ongoing), notes: 10 pounds of weight loss two week history. The patient's concomitant medications were not reported. Past drug history included: Sertraline for Anxiety disorder. Vaccination history included: Bnt162b2 (Dose 1, Single), for COVID-19 immunization. The following information was reported: THYROIDITIS (medically significant, life threatening), outcome "recovered", described as "Thyroiditis after mRNA Vaccination for COVID-19". The patient underwent the following laboratory tests and procedures: Anti-thyroid antibody (normal high range 10): 147 IU/ml, notes: elevated (normal range <10 IU/mL); Anti-thyroid antibody (normal high range 14): 1296.1 IU/ml, notes: elevated; Blood pressure measurement: 143/71 mmHg; Blood thyroid stimulating hormone (0.35-4.94): less than 0.01, notes: normal; 25 MiU/L, notes: 4 weeks later. elevated; normalized; Body temperature: 102.5 Fahrenheit; C-reactive protein (normal high range 5): 25 mg/l, notes: elevated (normal range <5 mg/L); Endocrine test: he was found to have suppressed TSH, notes: he was found to have suppressed TSH; Heart rate: 86, notes: Unit: minutes; 50's; Laboratory investigation: revealed undetectable TSH with normal T3 and T4, notes: Level; Respiratory rate: 18, notes: Unit: Unknown unit; Thyroid hormones test: revealed normal thyroid gland, notes: revealed normal thyroid gland with no-significant tenderness. he had no extrathyroidal features of Graves disease; Thyroid stimulating immunoglobulin (normal high range 1.75): less than 1.10, notes: (normal range <1.75 IU/l); Thyroid stimulating immunoglobulin: less than 0.10; Thyroxine: normal; Thyroxine free: low, notes: hypothyroid phase; Thyroxine free (0.9-1.8): 1.71 ng/dL; 0.40 ng/dL; Tri-iodothyronine (100-200): 139 ng/dL; normal; Ultrasound thyroid: showed diffusely heterogeneous gland, notes: showed diffusely heterogeneous gland with increased vascularity and no nodules; few large benign-appears lymph nodes, notes: few large benign-appears lymph nodes, which were resolved in follow-up ultrasound; Weight: 10 pounds of weight loss; White blood cell count (4-11): 5.3, notes: Unit: 10x3/ml. Therapeutic measures were taken as a result of thyroiditis.  Clinical course: Patient with a history of anxiety disorder treated with sertraline presented with a two week history of persistent palpitations, heat intolerance, and 10 pounds of weight loss. He reported no past or family history of thyroid disorders. He did not have any history of COVID-19 infection and was vaccinated with both doses of BNT162b2, 4 weeks apart. Soon after receiving the second vaccine dose, he developed a high-grade fever at 102.5 F, myalgia and sore throat, which persisted for 2 weeks. Subsequently, he experienced palpitations, diaphoresis and heat intolerance along with generalized weakness. An endocrinology referral was triggered as he was found to had suppressed TSH along with elevated CRP at his primary care provider's office. The patient was on levothyroxine was held in view of suppressed TSH and elevated free T4. Corticosteroid treatment was not recommended given the mild nature of the symptoms. Her symptoms gradually subsided over the subsequent few weeks, and TSH levels started rising. Levothyroxine therapy was restarted when the TSH level increased above the normal range. On physical examination, his heart rate was 86/min, blood pressure was 143/71, and respiratory rate was 18. A thyroid examination revealed a normal thyroid gland with no significant tenderness. He had no extrathyroidal features of Graves' disease. Repeat laboratory investigations revealed an undetectable TSH with normal T3 and T4 levels. Additional lab investigations revealed elevated thyroid peroxidase and thyroglobulin antibodies but undetectable levels of thyroid receptor antibodies and thyroid-stimulating immunoglobulin antibodies. An ultrasound of the thyroid showed a diffusely heterogeneous gland with increased vascularity and no nodules. The clinical features were consistent with silent thyroiditis. There were a few large benign-appears lymph nodes, which were resolved on follow-up ultrasound. His symptoms improved with NSAIDs without corticosteroid treatment. Repeat laboratory evaluation 4 weeks later revealed elevated TSH and low free T4 suggestive of a hypothyroid phase. He was transiently treated with levothyroxine because of severe fatigue and relative bradycardia with a heart rate of 50's. Levothyroxine was subsequently discontinued as his TSH normalized. He currently remains euthyroid and asymptomatic without levothyroxine supplementation.; Sender's Comments: Based on the available information in the case, the causal association between the event thyroiditis and the suspect drug BNT162B2 cannot be 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 to regulatory authorities, Ethics Committees, and Investigators, as appropriate.