Repeat sudden unexpected infant deaths/Authors' reply

We are well aware that SIDS is not a diagnosis but a label applied to a heterogeneous group of as yet unexplained lethal conditions that is being progressively reduced by research.4 Indeed, our late coauthor John Emery was among the first to suggest that some SIDS cases might be due to filicide.5 We attempted to look at an unselected series of deaths in infants enrolled on the CONI programme and found that for first unexpected infant deaths on CONI, 40 were natural and six unnatural (ratio 6.7/1). The nature of both the index death and the death on CONI were determined by complete enquiries in 27 (72%) pairs of deaths, and in 13 (28%) pairs we relied on the findings from Coroner's and Higher Courts. Of these 27 pairs, in nine, one or both deaths were due to recognised causes. In the remaining 18 our investigations found no explanation for either death. In addition there were two pairs of deaths that we described as probable double covert homicides. Hence for unexpected and unexplained infant deaths we found a ratio of nine natural to one unnatural.