"She has arthritis in her right knee  progressively got worse "& "exacerbation of arthritis in her leg"; She had difficulty walking; Difficulty stabilizing my leg/difficulty moving; had 2 episodes (yesterday & today) of severe weakness that starts in armpits & goes down her arms; make her feel weak & like she has no muscle strength; Severe Muscle pain; severe pain in  hip & severe pain in her right knee & Joint pain; pain in thigh; This spontaneous case was reported by a consumer and describes the occurrence of ARTHRITIS ("She has arthritis in her right knee  progressively got worse "& "exacerbation of arthritis in her leg"), GAIT DISTURBANCE (She had difficulty walking), MOBILITY DECREASED (Difficulty stabilizing my leg/difficulty moving), MUSCULAR WEAKNESS (had 2 episodes (yesterday & today) of severe weakness that starts in armpits & goes down her arms) and ASTHENIA (make her feel weak & like she has no muscle strength) in a 60-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 001M21A, 939909 and 012M20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Drug allergy (Demerol), Allergy to NSAIDs (diclofenac) and Arthritis. Concomitant products included COLECALCIFEROL (VITAMIN D [COLECALCIFEROL]), MULTIVITAMIN [VITAMINS NOS] and ESTRADIOL (ESTRACE) for an unknown indication.   On 08-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 05-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 01-Dec-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 21-Apr-2022, received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 22-Apr-2022, the patient experienced ARTHRALGIA (severe pain in  hip & severe pain in her right knee & Joint pain) and PAIN IN EXTREMITY (pain in thigh). On an unknown date, the patient experienced ARTHRITIS ("She has arthritis in her right knee  progressively got worse "& "exacerbation of arthritis in her leg"), GAIT DISTURBANCE (She had difficulty walking), MOBILITY DECREASED (Difficulty stabilizing my leg/difficulty moving), MUSCULAR WEAKNESS (had 2 episodes (yesterday & today) of severe weakness that starts in armpits & goes down her arms), ASTHENIA (make her feel weak & like she has no muscle strength) and MYALGIA (Severe Muscle pain). The patient was treated with IBUPROFEN at an unspecified dose and frequency. At the time of the report, ARTHRITIS ("She has arthritis in her right knee  progressively got worse "& "exacerbation of arthritis in her leg"), GAIT DISTURBANCE (She had difficulty walking) and MOBILITY DECREASED (Difficulty stabilizing my leg/difficulty moving) was resolving, MUSCULAR WEAKNESS (had 2 episodes (yesterday & today) of severe weakness that starts in armpits & goes down her arms), ASTHENIA (make her feel weak & like she has no muscle strength) and ARTHRALGIA (severe pain in  hip & severe pain in her right knee & Joint pain) outcome was unknown and PAIN IN EXTREMITY (pain in thigh) and MYALGIA (Severe Muscle pain) had not resolved.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   Company comment.  This spontaneous case concerns a 60  year  old, female patient with concurrent condition of arthritis, who experienced the unexpected, non  serious AESI of arthritis, among other non  serious event. The event occurred one day after the administration of the second booster dose of mRNA-1273 vaccine. The report stated that the patient experienced severe pain in her right knee, thigh, and hip, and was treated with ibuprofen for several days. The patient has arthritis in her right knee and progressively got worse. She used diclofenac gel on her hip, but since she is allergic to it, she mentioned it made it worse, with mobility decreased, gait disturbance, myalgia. She also mentioned asthenia and weakness in arms. No further details were provided for medical review. Patient´s medical history of arthritis could be confounder for arthritis. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 28-Apr-2022: Follow-up  Significant information accepted events added.; Sender's Comments: This spontaneous case concerns a 60  year  old, female patient with concurrent condition of arthritis, who experienced the unexpected, non  serious AESI of arthritis, among other non  serious event. The event occurred one day after the administration of the second booster dose of mRNA-1273 vaccine. The report stated that the patient experienced severe pain in her right knee, thigh, and hip, and was treated with ibuprofen for several days. The patient has arthritis in her right knee and progressively got worse. She used diclofenac gel on her hip, but since she is allergic to it, she mentioned it made it worse, with mobility decreased, gait disturbance, myalgia. She also mentioned asthenia and weakness in arms. No further details were provided for medical review. Patient´s medical history of arthritis could be confounder for arthritis. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.