Pneumonia; Thought she was bleeding internally; Platelets low; Took my lupus out of remission; 1st and 2nd vaccine I got was Pfizer; 1st booster was Pfizer; 2nd booster I got was the Novavax; Foot infection; So sick; Hands get numb; feet get numb; 1st and 2nd vaccine I got was Pfizer; 1st booster was Pfizer; 2nd booster I got was the Novavax; This serious initial spontaneous safety report was received by Novavax on 13-SEP-2023 from a consumer, via the contact center.  A female of 77 year-old was vaccinated with intramuscular use Novavax Covid-19 Vaccine and Adjuvanted 10 ug/mL suspect Covid-19 vaccine dose 4 (booster) on 19-AUG-2022 at a physician's office, in the left arm.  The following secondary suspect medications were reported: prednisone for 10 weeks at 6 mg, Plaquenil S (hydroxychloroquine sulfate) "in the beginning", IVIG 2-3 months ago for about 5 week and Nplate (romiplostim) injections for 7 weeks as of 13-SEP-2023.  The following medical history was reported: Hypersensitivity (sulfur), Rheumatoid arthritis and Systemic lupus erythematosus for 29 years. She reported 2 months before she received the vaccine her Systemic lupus erythematosus and Rheumatoid arthritis "were in good shape." On 27-OCT-2021, the individual was vaccinated dose 1. On unspecified dates she received dose 2 and dose 3 (first booster) of Pfizer BioNTech COVID-19 vaccine (tozinameran).  The following concomitant medications were reported: Klonopin (clonazepam) and Wellbutrin (bupropion hydrochloride).  On 19-AUG-2022, the individual was vaccinated with dose 4 of Novavax Covid-19 vaccine following dose 1, dose 2, and dose 3 (booster) of Pfizer BioNtech Covid-19 vaccine (PT: Off label use) (PT: COVID-19 immunisation). After vaccination, the individual was instructed to go back in 8 weeks for an additional dose, but the individual did not go back. On an unspecified date in 2022, after vaccination, the individual developed a foot infection (PT: Localised infection). On an unspecified date in 2022, a month or 2 after receiving the vaccine, the individual had low platelets (PT: Platelet count decreased) (Serious: Hospitalization). Her platelets went down to 2000 (units not reported). On 18-JAN-2023, the individual's lupus went out of remission (PT: Systemic lupus erythematosus) (Serious: Hospitalization and Medically Significant) reportedly because the vaccine "had too much protein," according to her physician. Subsequently, the individual was hospitalized for 5 days. The individual had been "so sick" since 18-JAN-2023 (PT: Illness). For treatment of the low platelets, the individual received Prednisone at 6 mg for 10 weeks and Plaquenil, and then the individual ended up with pneumonia (PT: Pneumonia) (Serious: Hospitalization and Medically Significant) and was subsequently hospitalized again. Then around JUN-2023 or JUL-2023, she was started in IVIG for about 5 weeks. After, she was started on Nplate injections, which made the individual "so sick." Her hands and feet would get numb (PT: Hypoaesthesia). The individual's platelets went up to 74,000, and subsequently concluded the Nplate was working. Additionally, on an unspecified date in JUL-2023, the individual was once again hospitalized because they thought she was bleeding internally (was not specified if this was confirmed) (PT: Internal haemorrhage) (Serious: Hospitalization and Medically Significant).   Relevant lab tests included: Platelet count (Result: 2000 (units not reported); unspecified date) and Platelet count (Result: 74,000 (units not reported); unspecified date).  On 19-AUG-2022, the event outcomes of COVID-19 immunisation and Off label use were recovered/resolved. At the time of reporting, the event outcomes of Platelet count decreased, Systemic lupus erythematosus, Illness, and Hypoaesthesia were not recovered/not resolved and Pneumonia, Internal haemorrhage, and Localised infection were unknown,; Sender's Comments: This 79 year-old female experienced: Systemic lupus erythematosus, Pneumonia, Internal haemorrhage, Platelet count decreased, COVID-19 immunisation, Localised infection, Off label use, Illness and Hypoaesthesia after vaccination with Novavax Covid-19 Vaccine, Adjuvanted 10 ug/mL. The events Systemic lupus erythematosus, Pneumonia, Internal haemorrhage and Platelet count decreased were reported as serious. The events COVID-19 immunisation, Localised infection, Off label use, Illness and Hypoaesthesia 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.