Exacerbated pre-existing arthritis of right shoulder; Pain so so severe at work; Pain is ongoing everyday of back right shoulder. States it is about a "level 4" of pain; Delayed getting the 2nd dose/Date of 1st dose: 29Apr2021/Date of 2nd dose: 10Jun2021; This spontaneous case was reported by a consumer and describes the occurrence of ARTHRITIS (Exacerbated pre-existing arthritis of right shoulder), PAIN (Pain so so severe at work), ARTHRALGIA (Pain is ongoing everyday of back right shoulder. States it is about a "level 4" of pain) and INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Delayed getting the 2nd dose/Date of 1st dose: 29Apr2021/Date of 2nd dose: 10Jun2021) in a 51-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 007C21A) for COVID-19 vaccination.     Concurrent medical conditions included Arthritis (Arthritis of right shoulder). Concomitant products included PARACETAMOL (TYLENOL [PARACETAMOL]) for Arthritis.    On 29-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 10-Jun-2021,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Delayed getting the 2nd dose/Date of 1st dose: 29Apr2021/Date of 2nd dose: 10Jun2021). On an unknown date, the patient experienced ARTHRITIS (Exacerbated pre-existing arthritis of right shoulder), PAIN (Pain so so severe at work) and ARTHRALGIA (Pain is ongoing everyday of back right shoulder. States it is about a "level 4" of pain). The patient was treated with MELOXICAM for Adverse event, at an unspecified dose and frequency; MENTHOL, METHYL SALICYLATE (SALONPAS [MENTHOL;METHYL SALICYLATE]) for Adverse event, at an unspecified dose and frequency; Physical therapy for Arthritis; Physical therapy for Pain and Physical therapy for Arthralgia. On 10-Jun-2021, INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Delayed getting the 2nd dose/Date of 1st dose: 29Apr2021/Date of 2nd dose: 10Jun2021) had resolved. At the time of the report, ARTHRITIS (Exacerbated pre-existing arthritis of right shoulder), PAIN (Pain so so severe at work) and ARTHRALGIA (Pain is ongoing everyday of back right shoulder. States it is about a "level 4" of pain) had not resolved.        mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosing was delayed on an unknown date.       Patient received 2nd dose on 10Jun2021 Lot number-034C21A left arm injection and Moderna booster on 15Oct2021 Lot number-037C21A left arm injection.  The pain lasted all the way to May. On 28 May 2021 she said the pain so severe at work, she "could not take it". She went to HCP 9 Jun 2021 due to severe pain. She states that the pain never went away since first dose.  Treatment medication also includes Tylenol, physical therapy for right arm/shoulder.  This case concerns a 51-year-old, female patient with medical history of ARTHRITIS, who experienced the unexpected AESI of ARTHRITIS, with concurrent expected nonserious event of ARTHRALGIA and unexpected nonserious event of PAIN, on an unknown date after the first dose of mRNA-1273 vaccine. INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION was also noted in this case. The events ARTHRITIS, PAIN and ARTHRALGIA are not resolved. The rechallenge was not applicable, as the outcome of the events are not recovered. The medical history of Arthritis remains a confounder. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report; Sender's Comments: This case concerns a 51-year-old, female patient with medical history of ARTHRITIS, who experienced the unexpected AESI of ARTHRITIS, with concurrent expected nonserious event of ARTHRALGIA and unexpected nonserious event of PAIN, on an unknown date after the first dose of mRNA-1273 vaccine. INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION was also noted in this case. The events ARTHRITIS, PAIN and ARTHRALGIA are not resolved. The rechallenge was not applicable, as the outcome of the events are not recovered. The medical history of Arthritis remains a confounder. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.