Anti-MDA5 ab DM with associated rapidly progressive interstitial lung disease (RP-ILD); Coronavirus disease (COVID) vaccine associated Anti-melanoma differentiation-associated gene 5-positive dermatomyositis (Anti-MDA5 ab DM); polyarticular joint pain; Pneumocystis pneumonia; acute hypoxic respiratory failure; progressive shortness of breath; malaise; weight loss; Initial information received on 04-Oct-2023 via Healthcare Professional from country regarding an unsolicited valid serious case issued from a literature article:      This case involves a 61-year-old female patient who experienced Coronavirus disease (COVID) vaccine associated Anti-melanoma differentiation-associated gene 5-positive dermatomyositis (Anti-MDA5 ab DM) (dermatomyositis) associated rapidly progressive interstitial lung disease (RP-ILD) while receiving vaccines COVID-19 VACCINE and INFLUENZA VACCINE (Latency: Unknown).  The patient's past medical treatment(s), vaccination(s) and family history were not provided. Patient was with a past medical history of hypothyroidism and untreated latent Tuberculosis (TB) (concurrent conditions).   On an unknown date, the patient received a dose of suspect INFLUENZA VACCINE produced by unknown manufacturer lot number not reported via unknown route in unknown administration site. On an unknown date, the patient received a dose of suspect COVID-19 VACCINE produced by unknown manufacturer lot number not reported via unknown route in unknown administration site. 1 other booster dose were administered on unknown dates for suspect COVID-19 VACCINE.  On an unknown date patient was evaluated as an outpatient on 4 occasions over a 2-month period for progressive shortness of breath(dyspnoea), polyarticular joint pain(arthralgia), weight loss (weight decreased) and malaise beginning shortly after her influenza and second COVID booster vaccine. She was referred to rheumatology and treated with short courses of prednisone for an inflammatory arthritis. Her symptoms progressed and she presented to the Emergency Department with acute hypoxic respiratory failure (acute respiratory failure) requiring high-flow nasal cannula. Initial workup was notable for severely elevated Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), elevated Partial thromboplastin time (PTT) and aspartate aminotransferase (AST), a normal white count with decreased lymphocytes, and 1+ protein on Urinalysis (UA). Chest imaging revealed extensive multifocal ground glass opacities. Within 24 hours she required intubation and transfer to the intensive care unit. Bronchoalveolar lavage was notable for a positive Pneumocystis jiroveci (pneumocystis jirovecii pneumonia) PCR (polymerase chain reaction) for which she was treated with trimethoprim/sulfamethoxazole (TMP/SMX) and methylprednisolone. On hospital day 6 she was initiated on venovenous (VV) extracorporeal membrane oxygenation (ECMO). Rheumatologic workup later revealed positive anti-MDA5 ab. Immunotherapy was initiated with high dose prednisone and then cyclophosphamide following treatment for Pneumocystis pneumonia (PJP). Unfortunately, she never experienced meaningful recovery of pulmonary function and as she was not a candidate for lung transplant, she eventually succumbed to her illness on hospital day 51.   Author stated that: We present a case of Anti-MDA5 ab DM with associated rapidly progressive interstitial lung disease (RP-ILD) (interstitial lung disease) after COVID and influenza vaccination. This patient with rapidly progressive interstitial lung disease due to Anti-MDA5 antibody-positive dermatomyositis was initially difficult to diagnose due to concern for other causes of acute respiratory failure, in particular PJP. Prior small studies have shown increased incidence of myositis-related anti- Ribonucleic Acid (RNA)-synthetases auto-antibodies after administration of COVID mRNA vaccine. Our suspicion is that this patient developed anti-MDA5 ab as a result of her COVID mRNA vaccination and subsequent development of RP-ILD was secondary to her anti-MDA5 DM. This case highlights the importance of recognition of this rare dermatomyositis, in particular given the rise of production of autoantibodies after widespread COVID vaccination. Despite this rare and catastrophic outcome, the benefits of COVID vaccination remain at the forefront of population health. Early recognition of the severe complication of RP-ILD may help with diagnosis and early initiation of directed therapies.   Seriousness criteria: hospitalization,  Action taken: not applicable for both suspects. Corrective treatment: venovenous (VV) ECMO, prednisone, cyclophosphamide, TMP/SMX, methylprednisolone and high-flow nasal cannula for both events Outcome: Fatal for both events Reporter's causality: Related wit all suspects for both events. It is unknown if an autopsy was done. The cause of death was reported as Dermatomyositis and Interstitial lung disease.; Sender's Comments: Sanofi company comment on dated 09-OCT-2023: This case involves a 61-year-old female patient who experienced Coronavirus disease (COVID) vaccine associated Anti-melanoma differentiation-associated gene 5-positive dermatomyositis (Anti-MDA5 ab DM) (dermatomyositis) associated rapidly progressive interstitial lung disease (RP-ILD) while receiving vaccines COVID-19 VACCINE and INFLUENZA VACCINE. Based on the limited information received the causal role of VACCINE cannot be excluded due to compatible temporal relationship of ADR to the VACCINE. Further information regarding previous vaccination, tolerance, allergic history, excluding alternative etiologies for the reported event are needed to fully assess this case. Based upon the reported information, the role of vaccine cannot be assessed completely.; Reported Cause(s) of Death: Coronavirus disease (COVID) vaccine associated Anti-melanoma differentiation-associated gene 5-positive dermatomyositis (Anti-MDA5 ab DM); Anti-MDA5 ab DM with associated rapidly progressive interstitial lung disease (RP-ILD)