post-COVID tachycardia; shortness of breath; fatigue; Initial COVID-19 infection prior to COVID-19 treatment; Patient received a dose of Janssen COVID-19 vaccine prior to mRNA-1273 vaccination; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (Initial COVID-19 infection prior to COVID-19 treatment), TACHYCARDIA (post-COVID tachycardia), DYSPNOEA (shortness of breath), FATIGUE (fatigue) and INTERCHANGE OF VACCINE PRODUCTS (Patient received a dose of Janssen COVID-19 vaccine prior to mRNA-1273 vaccination) in a 45-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 939902) for COVID-19 vaccination.     Previously administered products included for Product used for unknown indication: Janssen (Dose Number: 1  Batch/Lot No: 1805022 Location of injection: Arm Left  andVaccine Administration Time: 03:00 PM) on 08-Mar-2021. Past adverse reactions to the above products included No adverse event with Janssen. Concurrent medical conditions included Asthma, Hypertension, Anxiety, Allergy and Allergy to nuts (tree nuts). Concomitant products included FLUTICASONE PROPIONATE, SALMETEROL XINAFOATE (WIXELA INHUB) for an unknown indication.    On 25-Oct-2021 at 3:00 PM, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 25-Oct-2021, the patient experienced INTERCHANGE OF VACCINE PRODUCTS (Patient received a dose of Janssen COVID-19 vaccine prior to mRNA-1273 vaccination). On 02-Mar-2022, the patient experienced COVID-19 (Initial COVID-19 infection prior to COVID-19 treatment). On an unknown date, the patient experienced TACHYCARDIA (post-COVID tachycardia), DYSPNOEA (shortness of breath) and FATIGUE (fatigue). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 02-Mar-2022 to 07-Mar-2022 for COVID-19 treatment, at an unspecified dose and frequency. On 02-Apr-2022, TACHYCARDIA (post-COVID tachycardia), DYSPNOEA (shortness of breath) and FATIGUE (fatigue) had resolved. At the time of the report, COVID-19 (Initial COVID-19 infection prior to COVID-19 treatment) had resolved and INTERCHANGE OF VACCINE PRODUCTS (Patient received a dose of Janssen COVID-19 vaccine prior to mRNA-1273 vaccination) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 02-Mar-2022, SARS-CoV-2 test: positive (Positive) Positive. On 10-Mar-2022, SARS-CoV-2 test: negative (Negative) Negative. On 13-Mar-2022, SARS-CoV-2 test: positive (Positive) Positive.         On 27-Feb - patient had first COVID symptoms, 02-Mar patient had first positive test also received first Paxlovid dose and on 07-Mar received the last Paxlovid dose. On 08-Mar patient's symptoms were largely gone except for post-COVID tachycardia and shortness of breath / fatigue. On 10-Mar patient tested negative. 13-Mar (6 days after finishing the Paxlovid course) patient had COVID again with new symptoms (lost sense of smell) and tested positive again  Company Comment:  This is a spontaneous case concerning a 45-year-old male patient with no relevant medical history reported, who experienced the unexpected non-serious adverse event of special interest COVID-19, described as initial COVID-19 infection prior to COVID-19 treatment, which occurred approximately 4 months after receiving the a dose of mRNA-1273 as the second dose of COVID-19 vaccine. Patient had received a primary dose of Janssen COVID-19 vaccine with no reported adverse event, approximately 8 months prior to mRNA-1273 vaccination (Interchange of vaccine products). Initially, patient experienced unspecified COVID-19 symptoms and was tested positive for COVID-19 after 3 days. Patient was given a five-day-course of Paxlovid treatment for the initial COVID-19 infection and was tested negative for COVID-19 after three days. Patient reported that most of the symptoms were resolved except for post-COVID tachycardia, shortness of breath and fatigue. However, six days after the completion of Paxlovid treatment, patient noted loss of smell and was tested positive again for COVID-19. Outcome of the event for the initial COVID-19 infection had resolved. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a 45-year-old male patient with no relevant medical history reported, who experienced the unexpected non-serious adverse event of special interest COVID-19, described as initial COVID-19 infection prior to COVID-19 treatment, which occurred approximately 4 months after receiving the a dose of mRNA-1273 as the second dose of COVID-19 vaccine. Patient had received a primary dose of Janssen COVID-19 vaccine with no reported adverse event, approximately 8 months prior to mRNA-1273 vaccination (Interchange of vaccine products). Initially, patient experienced unspecified COVID-19 symptoms and was tested positive for COVID-19 after 3 days. Patient was given a five-day-course of Paxlovid treatment for the initial COVID-19 infection and was tested negative for COVID-19 after three days. Patient reported that most of the symptoms were resolved except for post-COVID tachycardia, shortness of breath and fatigue. However, six days after the completion of Paxlovid treatment, patient noted loss of smell and was tested positive again for COVID-19. Outcome of the event for the initial COVID-19 infection had resolved. The benefit-risk relationship of mRNA-1273 is not affected by this report.