Flu like symptoms; Spondylitis ankylosing aggravated; This spontaneous case was reported by a consumer and describes the occurrence of ANKYLOSING SPONDYLITIS (ANKYLOSING SPONDYLITIS FLARE PERSISTED DESPITE BEING ON HUMIRA FOR FOUR MONTHS) in a 48-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.  Co-suspect product included non-company product ADALIMUMAB (HUMIRA) solution for injection for Ankylosing spondylitis.  Concurrent medical conditions included Ankylosing spondylitis.  On 30-Dec-2020, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 27-Jan-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In 2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In July 2021, the patient started ADALIMUMAB (HUMIRA) (Subcutaneous) Citrate Free. In 2021, the patient experienced ANKYLOSING SPONDYLITIS (ANKYLOSING SPONDYLITIS FLARE PERSISTED DESPITE BEING ON HUMIRA FOR FOUR MONTHS) (seriousness criterion medically significant) and INFLUENZA LIKE ILLNESS (FLU LIKE SYMPTOMS AFTER THIRD COVID SHOT). In 2021, INFLUENZA LIKE ILLNESS (FLU LIKE SYMPTOMS AFTER THIRD COVID SHOT) had resolved. At the time of the report, ANKYLOSING SPONDYLITIS (ANKYLOSING SPONDYLITIS FLARE PERSISTED DESPITE BEING ON HUMIRA FOR FOUR MONTHS) had not resolved.   The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.    Concomitant drugs not reported.  In 2021, the patient experienced FLU LIKE SYMPTOMS AFTER THIRD COVID SHOT and ANKYLOSING SPONDYLITIS FLARE PERSISTED DESPITE BEING ON HUMIRA FOR FOUR MONTHS. In 2021, the FLU LIKE SYMPTOMS AFTER THIRD COVID SHOT resolved. No treatment medication was reported.  It was unknown if patient was enrolled in a Covid-19 Vaccine Trial. On 30 Dec 2020, patient received 1st dose Covid-19 Vaccine manufactured by Moderna.  Causality for HUMIRA(ADALIMUMAB): The reporter's causality for the event(s) of FLU LIKE SYMPTOMS AFTER THIRD COVID SHOT with HUMIRA(ADALIMUMAB) was no reasonable possibility. The reporter's causality for the event(s) of ANKYLOSING SPONDYLITIS FLARE PERSISTED DESPITE BEING ON HUMIRA FOR FOUR MONTHS onset in 2021 was not provided. The reporter's causality for the event(s) of ANKYLOSING SPONDYLITIS FLARE PERSISTED DESPITE BEING ON HUMIRA FOR FOUR MONTHS onset in 2021 with HUMIRA(ADALIMUMAB) was a reasonable possibility.  Company Comment: This spontaneous case concerns a 48-year-old, female patient with medical history of Ankylosing Spondylitis treated with the co-suspect product Humira (adalimumab), who experienced the unexpected, serious (medically significant) AESI of ankylosing spondylitis aggravated and an unexpected, non-serious event. The events occurred unknown number of days after receiving Humira and unknown number of days after receiving the third dose of the mRNA-1273 vaccine. Of note, the administration date of Humira was reported as unspecified date in Jul2021 and vaccination date of the third dose of the mRNA-1273 vaccine was reported as unspecified date in 2021 while the event onset dates were reported as unspecified dates in 2021, hence, the onset latency could not be assessed. It was reported that the patient experienced flu-like symptoms after vaccination and the Ankylosing Spondylitis flare persisted despite being on Humira for 4 months. The medical history of Ankylosing Spondylitis, an inflammatory disease characterized by flares and remission, remains a confounder for the event ankylosing spondylitis aggravated. The co-suspect product Humira also remains a confounder for the event ankylosing spondylitis aggravated. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.  This case was identified as part of a retrospective clean-up activity where certain emails received in the Moderna mailbox were missed to be booked-in.  Sender's Comments: This spontaneous case concerns a 48-year-old, female patient with medical history of Ankylosing Spondylitis treated with the co-suspect product Humira (adalimumab), who experienced the unexpected, serious (medically significant) AESI of ankylosing spondylitis aggravated and an unexpected, non-serious event. The events occurred unknown number of days after receiving Humira and unknown number of days after receiving the third dose of the mRNA-1273 vaccine. Of note, the administration date of Humira was reported as unspecified date in Jul2021 and vaccination date of the third dose of the mRNA-1273 vaccine was reported as unspecified date in 2021 while the event onset dates were reported as unspecified dates in 2021, hence, the onset latency could not be assessed. It was reported that the patient experienced flu-like symptoms after vaccination and the Ankylosing Spondylitis flare persisted despite being on Humira for 4 months. The medical history of Ankylosing Spondylitis, an inflammatory disease characterized by flares and remission, remains a confounder for the event ankylosing spondylitis aggravated. The co-suspect product Humira also remains a confounder for the event ankylosing spondylitis aggravated. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.