her knees and legs crumpled up; she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines; she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines; This spontaneous case was reported by a consumer and describes the occurrence of MALAISE (she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines), MUSCLE SPASMS (her knees and legs crumpled up) and CHILLS (she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines) in a 73-year-old female patient who received mRNA-1273.815 (SPIKEVAX 2023-2024) for COVID-19 prophylaxis.     Previously administered products included for Product used for unknown indication: Flu vaccine on 12-Oct-2023. Past adverse reactions to the above products included No adverse event with Flu vaccine. Concurrent medical conditions included Left ventricular dysfunction and Left bundle branch block.    On 07-Nov-2023, the patient received fifth dose of mRNA-1273.815 (SPIKEVAX 2023-2024) (unknown route) 1 dosage form. On 07-Nov-2023, the patient experienced MALAISE (she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines) and CHILLS (she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines). On 08-Nov-2023, the patient experienced MUSCLE SPASMS (her knees and legs crumpled up). On 09-Nov-2023, MUSCLE SPASMS (her knees and legs crumpled up) had resolved. At the time of the report, MALAISE (she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines) and CHILLS (she had the Spikevax on 07Nov2023 and in the afternoon had the usual chills and not feeling well which she also got after getting her previous Covid-19 vaccines) had resolved.        For mRNA-1273.815 (SPIKEVAX 2023-2024) (Unknown), the reporter did not provide any causality assessments.   Patient was on unspecified medication for left bundle branch block and left ventricular dysfunction. Patient had her 1st dose on 05-Mar-2021 (lot number: 032M20A), 2nd dose on 02-Apr-2021 (lot number: 045A21A), 3rd dose on 10-Nov-2021 (lot number: 039F21A) and 4th dose on 04-Oct-2022 (lot number: 057F22A).   On 07-Nov-2023 in afternoon patient experienced chills and was not feeling well. When patient woke up on 08-Nov-2023, after getting up from bed she went to their kitchen and her knees and legs crumpled up and she went down to the floor. She was able to do things in the kitchen and when she went back to her bedroom that happened again. She stayed in bed the whole day yesterday. Today, on 09-Nov-2023, it has not recurred. She called her doctor to consult this event and was waiting for their callback. Treatment medication was not reported.   This case was linked to MOD-2023-748946, MOD-2023-748947 (Patient Link).