Mild case of COVID-19; sick for a week and a half with COVID-19 symptoms around December and tested positive at this point; Contracted COVID from their unvaccinated son; Novavax as 2nd Booster after 2 doses J&J; Subclinical infection (of COVID-19); Mild case of COVID-19; sick for a week and a half with COVID-19 symptoms around December and tested positive at this point; Sick for a week and a half with COVID-19 symptoms; Little to no symptoms from the vaccine; Novavax as 2nd Booster after 2 doses J&J; Soreness at the injection site; Fatigue symptoms; This non-serious, initial spontaneous safety report from country was received by Novavax on 26-SEP-2023 from a consumer, via the contact center and customer experience centre.  A 67 year-old male of an unspecified race was vaccinated with intramuscular use Novavax Covid-19 Vaccine and Adjuvanted 10 ug/mL suspect Covid-19 vaccine dose 3 (reported as a second booster) on an unspecified day in NOV-2022 at a pharmacy in the left arm.  The following medical history was reported: Cough, Fatigue, Pain, Pyrexia, and vaccination with Janssen (COVID-19 vaccine NRVV Ad26 (JNJ 78436735)) dose 1 on 25-OCT-2021 (primary series) and dose 2 (booster) on an unspecified date.  No concomitant medications were reported.  On an unspecified day in NOV-2022, the individual was vaccinated with Novavax Covid-19 vaccine as 2nd booster, following a primary series and 1 booster of Janssen (PT: Off label use) (PT: COVID-19 immunisation). He reported little to no symptoms from the vaccine (PT: Unevaluable event).  On an unspecified day in DEC-2022, about a month after vaccination, the individual experienced mild case of covid-19 (PT: Breakthrough COVID-19).  At the time of reporting, the event outcomes of Off label use, Breakthrough COVID-19, COVID-19 immunisation and Unevaluable event were recovered/resolved.  On 26-SEP-2023, significant additional information was received from a consumer, and was received by Novavax on 05-OCT-2023 via the contact center. The following information was updated in the case: On an unreported date in 2022, after vaccination, the individual was exposed to COVID-19 (PT: Exposure to SARS-CoV-2). On an unspecified day in NOV-2022, after vaccination, the individual experienced soreness at the injection site (PT: Vaccination site pain) and fatigue symptoms (PT: Fatigue), which all dissipated within 36 hours. On an reported day in NOV-2022, he had a possible subclinical infection of COVID-19 (PT: COVID-19).  On an unspecified day in DEC-2022, he was sick for a week and a half with COVID-19 symptoms (PT: Illness) and tested positive (PT: Vaccination failure). At the time of vaccination, the event outcome of Vaccination failure was recovered/resolved. At the time of reporting, the event outcomes of Exposure to SARS-CoV-2, Vaccination site pain, Illness, and Fatigue were recovered/resolved, and event stop dates were unknown.; Sender's Comments: This 67 year-old male experienced: Vaccination failure, Exposure to SARS-CoV-2, Unevaluable event, COVID-19, COVID-19 immunisation, Fatigue, Off label use, Vaccination site pain, Breakthrough COVID-19 and Illness after vaccination with Novavax Covid-19 Vaccine, Adjuvanted 10 ug/mL. The event Vaccination failure was assessed as serious. The events Exposure to SARS-CoV-2, Unevaluable event, COVID-19, COVID-19 immunisation, Fatigue, Off label use, Vaccination site pain, Breakthrough COVID-19 and Illness were reported as non-serious. Based on the spontaneous nature of the report, the causal relationship between Novavax Covid-19 Vaccine, Adjuvanted and the reported events is considered Possible.