Unexplained sudden death, including sudden infant death syndrome (SIDS), in the first and second years of life

Need for developing case definitions and guidelines for unexplained sudden death as an adverse event following immunization:

Translations of the terms “cot death” or “sudden infant death” have been used in most European languages since medieval times. They describe the unexpected discovery of a dead infant in the cot or bed. The suddenness of the death itself remains somewhat speculative, because it generally occurs at an unknown interval after the child was last seen alive and apparently well.

Since infant primary immunization schedules temporally coincide with the peak age for the incidence of sudden infant death syndrome (SIDS), speculation about the association of immunization and SIDS may arise when deaths follow vaccinations, despite their predictable occurrence by chance alone [1], [2]. A number of studies have shown that immunization does not increase the risk of SIDS [3], [4], [5], [6], [7]. In the scientific literature since 1952 the terms “sudden” and “unexpected” have been used to describe these deaths without implying whether there was a known cause or not [8]. In order to enable the standardized assessment and to improve comparability of case reports of unexplained sudden deaths after vaccinations, the Unexplained Sudden Death Working Group was initiated by the Brighton Collaboration to develop a case definition and guidelines for reporting unexplained sudden deaths in the first and second years of life. The standardized case definition and guidelines provided in this document aim to improve reliability and comparability of data collected from immunized patients and controls in studies. Such data can contribute to the assessment of whether or to what extent each vaccine may contribute to the subsequent development of unexplained sudden death in the first and second years of life. The case definition and guidelines are intended to be applicable in diverse geographic, administrative, and cultural regions, regardless of differences in the availability of health care and resources.

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