seizures or seizure like activity; chest pains; hypo or hypertension; Blood pressure increased; This spontaneous case was reported by an other health care professional and describes the occurrence of SEIZURE (seizures or seizure like activity) in a 91-year-old female patient who received mRNA-1273.815 (SPIKEVAX 2023-2024) (batch no. 8058877) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Falling and Generalized muscle weakness. Previously administered products included for COVID-19 prophylaxis: Moderna (Dose 1) on 17-Mar-2021, Moderna (Dose 2) on 14-Apr-2021, Moderna (Dose 3) on 17-Dec-2021, PFIZER BIONTECH COVID-19 VACCINE and BIVALENT (ORIGINAL AND OMICRON BA.4/5) (Dose 4) on 24-Apr-2023. Past adverse reactions to the above products included No adverse event with Moderna, Moderna, Moderna, PFIZER BIONTECH COVID-19 VACCINE and BIVALENT (ORIGINAL AND OMICRON BA.4/5). Concurrent medical conditions included Atherosclerotic cardiovascular disease (Atherosclerotic heart disease of native coronary artery without angina pectoris), Adult failure to thrive, Atrioventricular block first degree, Hyperlipidemia (unspecified), Chronic kidney disease (unspecified, long term (current) use of aspirin), Unspecified vitamin D deficiency, Anemia vitamin B12 deficiency (unspecified), Protein-calorie malnutrition (Moderate), Unsteadiness (on feet), Unspecified hypothyroidism and Hypertensive heart disease (Hypertensive heart and chronic kidney disease without heart failure, with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease). Concomitant products included ACETYLSALICYLIC ACID (ASPIRIN (E.C.)) for Heart disorder, BISOPROLOL FUMARATE, CLONIDINE HCL and FUROSEMIDE (LASIX [FUROSEMIDE]) for Hypertension, LEVOTHYROXINE SODIUM and LISINOPRIL for Hypothyroidism, DICLOFENAC SODIUM (VOLTAREN [DICLOFENAC SODIUM]) from 20-Jul-2023 to 01-Aug-2023 for Osteoarthritis, ACETAMINOPHEN and PARACETAMOL (TYLENOL) for Pain, CYANOCOBALAMIN for Vitamin B12 deficiency, VITAMIN D3 for Vitamin D deficiency.    On 08-Nov-2023 at 11:29 AM, the patient received fifth dose of mRNA-1273.815 (SPIKEVAX 2023-2024) (Intramuscular use) 1 dosage form. On 09-Nov-2023 at 12:39 PM, the patient experienced SEIZURE (seizures or seizure like activity) (seriousness criterion medically significant), CHEST PAIN (chest pains), BLOOD PRESSURE FLUCTUATION (hypo or hypertension) and HYPERTENSION (Blood pressure increased). At the time of the report, SEIZURE (seizures or seizure like activity), CHEST PAIN (chest pains), BLOOD PRESSURE FLUCTUATION (hypo or hypertension) and HYPERTENSION (Blood pressure increased) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood pressure measurement: 152/96.     For mRNA-1273.815 (SPIKEVAX 2023-2024) (Intramuscular use), the reporter did not provide any causality assessments.   Patient age was reported as 91 years and 10 months.  It was reported that 9 patients who had adverse events after getting the Spikevax vaccine had common adverse events - chest pains, hypo or hypertension and seizures or seizures like activity.  No treatment medication information was reported. Company Comment: This is a spontaneous case concerning a 91-year-old female patient with a history of Atherosclerotic cardiovascular disease, Atrioventricular block first degree, Hyperlipidemia, Chronic kidney disease, hypothyroidism and Hypertensive heart disease, who experienced the serious (due to medically significant) unexpected, AESI event of Seizure, together with other non-serious events,  which  occurred on the following day after a dose of mRNA-1273.815 (SPIKEVAX 2023-2024)vaccine, received as the fifth dose of COVID-19 vaccination schedule. The outcome of the event was reported as recovered. The mentioned medical history remains as a confounder. The benefit-risk relationship of mRNA-1273.815 (SPIKEVAX 2023-2024) vaccine is not affected by this report.   This case was linked to US-MODERNATX, INC.-MOD-2023-749140 (E2B Linked Report).   Most recent FOLLOW-UP information incorporated above includes: On 10-Nov-2023: Significant follow-up received. Lot number updated. Reference number added. On 10-Nov-2023: Live follow-up received with significant information with vaccine details. On 10-Nov-2023: Live significant follow up received. Patient demographics, Concomitant medications, event added. On 13-Nov-2023: Follow-up received that contains non-significant information: Reporter and Reference IDs updated. On 13-Nov-2023: Significant follow up added. Reporter and LRM was added. Patient age group added.; Sender's Comments:  US-MODERNATX, INC.-MOD-2023-749140:Master case