COVID-19 infection; Confirmed Clinical Vaccination Failure; Received first dose Janssen, second and third dose Moderna; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (COVID-19 infection) and VACCINATION FAILURE (Confirmed Clinical Vaccination Failure) in a 39-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 033F21A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product COVID-19 VACCINE NRVV AD26 (JNJ 78436735) (JANSSEN COVID-19 VACCINE) for Prophylactic vaccination.    Concurrent medical conditions included Drug allergy.   On 20-Mar-2021, the patient received first dose of COVID-19 VACCINE NRVV AD26 (JNJ 78436735) (JANSSEN COVID-19 VACCINE) (unknown route) 1 dosage form. On 31-Oct-2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 06-May-2022, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 31-Oct-2021, the patient experienced INTERCHANGE OF VACCINE PRODUCTS (Received first dose Janssen, second and third dose Moderna). On 10-May-2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced COVID-19 (COVID-19 infection) (seriousness criterion medically significant) and VACCINATION FAILURE (Confirmed Clinical Vaccination Failure) (seriousness criterion medically significant). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 10-May-2022 to 15-May-2022 for COVID-19 treatment, at a dose of 1 UNK. At the time of the report, COVID-19 (COVID-19 infection) had not resolved and VACCINATION FAILURE (Confirmed Clinical Vaccination Failure) and INTERCHANGE OF VACCINE PRODUCTS (Received first dose Janssen, second and third dose Moderna) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 10-May-2022, SARS-CoV-2 test: positive (Positive) Positive. On 20-May-2022, SARS-CoV-2 test: positive (Positive) Positive thick and clear line. On an unknown date, SARS-CoV-2 test: positive (Positive) Positive result with a fading positive line.         No concomitant medication was provided.  The patient was not taking any other medications/products within 2 weeks of starting Covid-19 treatment. On 31-Oct-2021, the patient received booster dose of Spikevax. Patient began to take paxlovid (confirmed clinical vaccination failure) for Covid-19 treatment. He took full course of pills and felt better each day, several home antigen tests and each one showed a positive result but with a fading positive line. On 20-May-2022 the patient felt the symptoms returning and he took another test and found the positive line thick and clear which indicated that his viral load had increased since getting off paxlovid.  Company Comment: This spontaneous case reported by a patient concerns a 40-year-old male patient, with no relevant medical history, who experienced unexpected, serious (medically significant) AESI Covid-19 (laboratory confirmed) around 4 days after receiving a booster dose of mRNA-1273 (third dose in a Covid19 vaccination schedule).  Vaccination failure was also reported.  He was treated with a course of Paxlovid and was starting to feel better.  However, 5 days after Paxlovid completion the patient felt symptoms returning and tested positive again for Covid19.  Additionally, the patient previously received a different Covid19 vaccine Janssen as his initial dose (interchange of vaccine products).  The ongoing Covid19 pandemic could be a contributory factor.  The benefit risk relationship of mRNA-1273 is not affected by this report.   Reporter did not allow further contact; Sender's Comments: This spontaneous case reported by a patient concerns a 40-year-old male patient, with no relevant medical history, who experienced unexpected, serious (medically significant) AESI Covid-19 (laboratory confirmed) around 4 days after receiving a booster dose of mRNA-1273 (third dose in a Covid19 vaccination schedule).  Vaccination failure was also reported.  He was treated with a course of Paxlovid and was starting to feel better.  However, 5 days after Paxlovid completion the patient felt symptoms returning and tested positive again for Covid19.  Additionally, the patient previously received a different Covid19 vaccine Janssen as his initial dose (interchange of vaccine products).  The ongoing Covid19 pandemic could be a contributory factor.  The benefit risk relationship of mRNA-1273 is not affected by this report.