Since January 1965, a study of the sudden infant death syndrome (SIDS) in King County, Washington, has been conducted. Between August 1966 and June 1968, major changes in the protocol included the study of SIDS patients and controls as soon as possible after death, with extensive respiratory sampling, and strict avoidance of freezing of specimens before inoculation into tissue cultures. With use of this protocol, "significant" (nonpoliovirus) isolates were found in 37.5% of SIDS cases and in only 16.2% of controls. A diversity of serotypes was found. Viruses may have a significant role in the pathogenesis of SIDS, and some serotypes may have relatively greater importance than others. However, until the pathogenesis of this syndrome is more clearly defined, the relative significance of any single factor must remain speculative.
Ray CG, Beckwith JB, Hebestreit NM, Bergham AB. Studies of the Sudden Infant Death Syndrome in King County, WashingtonI. The Role of Viruses. JAMA. 1970;211(4):619–623. doi:10.1001/jama.1970.03170040023004