Revaccination with different COVID-19 vaccine; Interchange of vaccine products; She was diagnosed with Bolis Pemphigoid/she started to get extremely weird sores in her mouth on her tongue, gums, and cheeks. These sores turned into sacks that hung down with fluid in them. These sores burst.; This spontaneous case was reported by a patient and describes the occurrence of PEMPHIGOID (She was diagnosed with Bolis Pemphigoid/she started to get extremely weird sores in her mouth on her tongue, gums, and cheeks. These sores turned into sacks that hung down with fluid in them. These sores burst.) in a 66-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 1245J21A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     Previously administered products included for COVID-19 prophylaxis: Moderna COVID-19 Vaccine (Dose 1, lot number 040821A) on 08-Apr-2021, Moderna COVID-19 Vaccine (Dose 2 and lot number 004C21A) on 06-May-2021. Past adverse reactions to the above products included No adverse event with Moderna COVID-19 Vaccine and Moderna COVID-19 Vaccine.    On 30-Nov-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In May 2022, the patient experienced PEMPHIGOID (She was diagnosed with Bolis Pemphigoid/she started to get extremely weird sores in her mouth on her tongue, gums, and cheeks. These sores turned into sacks that hung down with fluid in them. These sores burst.) (seriousness criterion medically significant). On 14-Dec-2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products). At the time of the report, PEMPHIGOID (She was diagnosed with Bolis Pemphigoid/she started to get extremely weird sores in her mouth on her tongue, gums, and cheeks. These sores turned into sacks that hung down with fluid in them. These sores burst.) had not resolved and COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Concomitant medication details not reported by the reporter. Patient did not received any other vaccines in the 4 weeks prior to COVID-19 vaccine. Patient received PFIZER BIONTECH COVID-19 VACCINE  on 14-DEC-2022 with batch number GJ6796 for unknown indication. It was reported that about a year ago after the 3rd vaccination patient started to get extremely weird sores in her mouth on her tongue, gums, and cheeks. These sores turned into sacks that hung down with fluid in them. These sores burst. Patient gum lining would shed down in sheets. Any time one of the sores would heal up 2 more would come in its place. Patient could not brush her teeth because gums were macerated. Patient went to oral surgeon, dentist, and periodontist. One day when they were really bad, patient went to the periodontist without an appointment. Patient was diagnosed with Bolis Pemphigoid, a very rare autoimmune disease that attacks the mucous membranes. Usually in response to something immunological or stressful. Patient also had some dental procedure before these started in addition to her COVID vaccines. Symptoms started May 2022. No medications or treatments at this time Company comment This spontaneous case concerns an elderly female patient, with no medical history reported, who experienced the unexpected serious (medically significant) event of Pemphigoid, which occurred almost 6 months after the third dose of mRNA1273 vaccine. Patient received a dose of Pfizer COVID-19 Vaccine afterwards, therefore, Interchange of vaccine products, Revaccination with different COVID-19 vaccine were considered as additional events. It was reported that about a year ago after the 3rd vaccination patient started to get extremely weird sores in her mouth on her tongue, gums, and cheeks. These sores turned into sacks that hung down with fluid in them. These sores burst. Patient gum lining would shed down in sheets. Any time one of the sores would heal up and 2 more would come in its place. Patient co; Sender's Comments: This spontaneous case concerns an elderly female patient, with no medical history reported, who experienced the unexpected serious (medically significant) event of Pemphigoid, which occurred almost 6 months after the third dose of mRNA1273 vaccine. Patient received a dose of Pfizer COVID-19 Vaccine afterwards, therefore, Interchange of vaccine products, Revaccination with different COVID-19 vaccine were considered as additional events. It was reported that about a year ago after the 3rd vaccination patient started to get extremely weird sores in her mouth on her tongue, gums, and cheeks. These sores turned into sacks that hung down with fluid in them. These sores burst. Patient gum lining would shed down in sheets. Any time one of the sores would heal up and 2 more would come in its place. Patient could not brush her teeth because gums were macerated. Patient went to oral surgeon, dentist, and periodontist. One day when they were bad, patient went to the periodontist without an appointment. Patient was diagnosed with Bolis Pemphigoid, a very rare autoimmune disease that attacks the mucous membranes. Usually in response to something immunological or stressful. Patient also had some dental procedure before these started in addition to her COVID vaccines. No further clinical information was provided. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.