{Reference Type}: Journal Article {Title}: Multisystem inflammatory syndrome in children and adults (MIS-C/A): Case definition & guidelines for data collection, analysis, and presentation of immunization safety data. {Author}: Vogel TP;Top KA;Karatzios C;Hilmers DC;Tapia LI;Moceri P;Giovannini-Chami L;Wood N;Chandler RE;Klein NP;Schlaudecker EP;Poli MC;Muscal E;Munoz FM; {Journal}: Vaccine {Volume}: 39 {Issue}: 22 {Year}: 05 2021 21 {Factor}: 4.169 {DOI}: 10.1016/j.vaccine.2021.01.054 {Abstract}: This is a Brighton Collaboration Case Definition of the term "Multisystem Inflammatory Syndrome in Children and Adults (MIS-C/A)" to be utilized in the evaluation of adverse events following immunization. The case definition was developed by topic experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of vaccines for SARS-CoV-2. The format of the Brighton Collaboration was followed, including an exhaustive review of the literature, to develop a consensus definition and defined levels of certainty. The document underwent peer review by the Brighton Collaboration Network and by selected expert external reviewers prior to submission. The comments of the reviewers were taken into consideration and edits incorporated into this final manuscript.