inflammatory arthritis; pain; she had swollen ankles, feet, toes, shoulder blade, neck elbow, hands, her bones; chills; her temperature was 100°F; her hands are swollen and sore; was not able to sleep all night; This spontaneous case was reported by an other health care professional and describes the occurrence of ARTHRITIS (inflammatory arthritis), PAIN (pain), INSOMNIA (was not able to sleep all night), PERIPHERAL SWELLING (she had swollen ankles, feet, toes, shoulder blade, neck elbow, hands, her bones) and PYREXIA (her temperature was 100°F) in a 62-year-old female patient who received mRNA-1273.815 (SPIKEVAX 2023-2024) (batch no. ASKU) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product INFLUENZA VACCINE (INFLUENZA) for an unknown indication.    The patient's past medical history included COVID-19. Concurrent medical conditions included Rheumatoid arthritis since 2021, Asthma since 2021, Asthma since 2021, Migraine since 2021 and Acid reflux (esophageal). Concomitant products included OXITRIPTAN (TRIPTAN [OXITRIPTAN]), RIZATRIPTAN BENZOATE (MAXALT), RIZATRIPTAN, BACLOFEN and FAMOTIDINE (PEPCID [FAMOTIDINE]) for Acid reflux (esophageal), FLUTICASONE PROPIONATE (FLOVENT) for Asthma, SALBUTAMOL (VENTOLIN [SALBUTAMOL]) for Migraine, ASPIRIN [ACETYLSALICYLIC ACID] for Pain.   On 30-Oct-2023, the patient received dose of mRNA-1273.815 (SPIKEVAX 2023-2024) (unknown route) 1 dosage form and dose of INFLUENZA VACCINE (INFLUENZA) (unknown route) 1 dosage form. In October 2023, the patient experienced INSOMNIA (was not able to sleep all night), PYREXIA (her temperature was 100°F) and PAIN IN EXTREMITY (her hands are swollen and sore). On 30-Oct-2023, the patient experienced ARTHRITIS (inflammatory arthritis), PAIN (pain), PERIPHERAL SWELLING (she had swollen ankles, feet, toes, shoulder blade, neck elbow, hands, her bones) and CHILLS (chills). At the time of the report, ARTHRITIS (inflammatory arthritis), PAIN (pain), PERIPHERAL SWELLING (she had swollen ankles, feet, toes, shoulder blade, neck elbow, hands, her bones) and CHILLS (chills) was resolving and INSOMNIA (was not able to sleep all night), PYREXIA (her temperature was 100°F) and PAIN IN EXTREMITY (her hands are swollen and sore) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Body temperature: 100 Farad.     For mRNA-1273.815 (SPIKEVAX 2023-2024) (Unknown), the reporter did not provide any causality assessments.   Patient already received all of her Moderna doses but did not remember dates, she mentioned she had 2 doses of the primary series and did not remember how many boosters, but she received 1 booster on DEC 2022 and then the last dose it was Spikevax given on 30 OCT 2023, of noticed she also received flu shot on the same day. With the last dose with Spikevax she had a so much more acute or severe reaction like inflammatory arthritis, her temperature was 100°F and got chills, within a few hours it got worse and she had significant pain and was not able to sleep all night, she had swollen ankles, feet, toes, shoulder blade, neck elbow, hands, her bones; at 2 am she decided to take aspirin 81 mg. On 31 OCT 2023 symptoms are improving but not resolved yet. As background, caller mentioned that 2 years ago, she did not remember how many doses of the COVID-19 she had received but started having health issues, her rheumatologist mentioned it could be rheumatoid arthritis or psoriatic arthritis but was not able to identify the disease precisely, and this is still ongoing, when she does heavy hard work for her hands are swollen and sore at least for a week.  Treatment medication were added.  Company Comment: This is a Spontaneous case concerning a 62-year-old female patient with relevant medical history of Rheumatoid arthritis, who experienced the non-serious unexpected AESI of Arthritis which occurred on the same day after a dose of mRNA-1273.815 for COVID-19 Vaccination. The medical history of Rheumatoid arthritis remains a strong confounder. No further diagnostic tests results were disclosed for analysis. Concomitant vaccination with influenza vaccine remains confounding. The benefit-risk relationship of mRNA-1273.815 is not affected by this report.   This case was linked to MOD-2023-747858 (Patient Link).