ORBITAL CELLULITIS (RIGHT); This 69 -year-old, female subject was participating in A Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1273 SARS-CoV-2 Vaccine in Adults Aged 18 Years and Older (mRNA-1273-P301) and experienced the serious adverse event of orbital cellulitis (right).    The subject's medical history, as provided by the investigator, included hyperlipidemia, hysterectomy, uterine fibroids, and degenerative disc disease. Concomitant medications included calcium citrate, loratadine/ pseudoephedrine sulfate, influenza vaccine, estradiol, and non-study booster Pfizer Biontech COVID-19 vaccine.   The subject was randomized to receive intramuscular Placebo (dosed on 14 Sep 2020 and 12 Oct 2020) and was unblinded on 30 Dec 2020. The subject consented to receive mRNA-1273 for SARS-CoV-2 vaccination after being unblinded and, prior to event onset, the subject received mRNA-1273 (Dose 3, Booster) SARS-CoV-2 vaccination on 01 Oct 2021, approximately 1 year 30 days before onset of the event.  On 30 Oct 2022, the subject developed orbital cellulitis (right) and was admitted to the hospital. No treatment information was reported by the investigator.  On 02 Nov 2022, the subject was discharged from the hospital.  On 14 Nov 2022, the subject completed the study.  The subject received all scheduled doses of study drug prior to the event; therefore, action taken with study drug in response to the event was not applicable.   The event, orbital cellulitis (right), was reported as resolved on 10 Nov 2022.    The investigator assessed the event, orbital cellulitis (right), as related to study drug, not related to study procedure, and not related to non-study booster.  Company comment: This case concerns a 67-year-old, female subject with a medical history of hyperlipidemia among others, who experienced the unexpected event of orbital cellulitis (right). The event occurred 1 year 10 months after the first dose of mRNA-1273 administration and 1 year 29 days after the third and booster dose. The subject also received 4th and 5th dose (second and third boosters) of the study vaccine Pfizer, outside the study, 3 month 15 days, and 1 month 15 days, respectively, before the event onset. The event, orbital cellulitis (right), was reported as resolved. The investigator assessed the event, orbital cellulitis (right), as related to study drug, not related to study procedure, and not related to non-study booster. The sponsor considers the event as not related to the study vaccine based on the lack of biological plausibility and long latency to the event onset. Recurrent upper respiratory tract infections, suggested by the indication of concomitant medications, might provide an alternative explanation. It is to note that the information provided is very limited as circumstances leading to the event such as recent of trauma, insect bite, dental infections, or eyelid injuries, supportive diagnostics, clinical course and treatment, that would contribute the assessment of the case were not provided. Additional information was requested, and the case will be reassessed when more information becomes available.On 14 Nov 2022, the subject completed the study.