Retrospective study: A research design used to test etiologic hypotheses in which inferences about exposure to the putative causal factor(s) are derived from data relating to characteristics of the persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or other outcome or condition of interest, and their characteristics and past experiences are compared with those of unaffected persons.4
Rheumatoid arthritis: A generalized disease, occurring more often in women, which primarily affects connective tissue; arthritis is the dominant clinical manifestation, involving many joints, especially those of the hands and feet, accompanied by thickening of articular soft tissue, with extension of synovial tissue over articular cartilages, which become eroded; the course is variable but often is chronic and progressive, leading to deformities and disability.1
Rubella: An acute but mild exanthematous disease caused by rubella virus (Rubivirus family Togaviridae), with enlargement of lymph nodes, but usually with little fever or constitutional reaction; a high incidence of birth defects in children results from maternal infection during the first trimester of fetal life (congenital rubella syndrome).1
Seizure: A violent spasm or series of jerkings of the face, trunk, or extremities. Also known as convulsions.1
Self-controlled case-series study: The method, like the case-crossover method, uses cases as their own controls. However, the similarity stops there, as the case-series method derives from cohort rather than case-control logic. In particular, ages at vaccination are regarded as fixed, and the random variable of interest is the age at adverse event, conditionally on its occurrence within a predetermined observation period.6
Serum sickness: An immune complex disease appearing some days (usually 1–2 weeks) after injection of a foreign serum or serum protein, with local and systemic reactions such as urticaria, fever, general lymphadenopathy, edema, arthritis, and occasionally albuminuria or severe nephritis; originally described in patients receiving serotherapy.1
Shingles: See Herpes zoster.
Small fiber neuropathy: Neuropathy of small unmyelinated axons.8