Extreme muscle weakness/unable to play tennis; stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms; stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms; stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms; Also night time tingling which adversely affect my ability to sleep Worse in the mornings; This spontaneous case was reported by a patient and describes the occurrence of MUSCULAR WEAKNESS (Extreme muscle weakness/unable to play tennis), MUSCULOSKELETAL STIFFNESS (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms), PAIN IN EXTREMITY (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms), DYSSTASIA (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms) and PARAESTHESIA (Also night time tingling which adversely affect my ability to sleep Worse in the mornings) in an 85-year-old male patient who received mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (batch no. AS7184B) for COVID-19 prophylaxis.     The patient's past medical history included COVID-19 on 20-Sep-2022. Concomitant products included PARACETAMOL (TYLENOL) for an unknown indication.    On 02-Aug-2023, the patient received dose of mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (Intramuscular use) 1 dosage form. On 04-Aug-2023, the patient experienced MUSCULAR WEAKNESS (Extreme muscle weakness/unable to play tennis), MUSCULOSKELETAL STIFFNESS (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms), PAIN IN EXTREMITY (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms), DYSSTASIA (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms) and PARAESTHESIA (Also night time tingling which adversely affect my ability to sleep Worse in the mornings). At the time of the report, MUSCULAR WEAKNESS (Extreme muscle weakness/unable to play tennis), MUSCULOSKELETAL STIFFNESS (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms), PAIN IN EXTREMITY (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms), DYSSTASIA (stiffness and soreness in both legs, cannot put my socks on or do deep knee bend, cannot stand up without using my arms) and PARAESTHESIA (Also night time tingling which adversely affect my ability to sleep Worse in the mornings) had not resolved.        For mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (Intramuscular use), the reporter did not provide any causality assessments.   The patient was taking Tylenol every morning and evening before bed. With a good steam and jacuzzi patient was getting better during the day but comes back every night. No medicines were prescribed. Patient performed Complete blood tests' and a separate muscle enzyme test'; however, results were not reported.