Without going into the rather extensive research on toxicity and vaccinations (and there have been many threads here which cover the topic), I'd like to ask the question which none of the proponents of the 'toxicity' theory as a probable cause of SIDS seem to address - why is there no evidence of toxicity found in those infants affected by SIDS?

Any other animal that is affected by the toxicity of a substance will show evidence of that substance in their blood and cells - so why not SIDS babies? I've yet to see any conclusive evidence demonstrating the effects of toxicity, neither is their any statistical evidence to show that SIDS is more prevalent amongst infants raised in houses built within the last (say) twenty years. In all likelihood the opposite could be inferred from the data, as the SIDS rate showed a marked decrease from the time it peaked in 1986 to 2000 (from 568 to 134 deaths).

The research undertaken to support the hypothesis that toxic gases from mattresses has been discredited, with the results unable to be replicated. One study did suggest a link between used mattresses and a higher rate of SIDS, but 'it is not known what condition these mattresses were in or what position these babies slept in. There is no evidence to show that the risk of SIDS increases for babies who sleep on their back and on a firm, clean, well fitting mattress that is in good condition.' Whilst the evidence relating to toxicity may be seen to conflict with advice given in relation to the increased risk of the children of smokers my understanding is that this relates specifically to carbon monoxide - which is associated with breathing difficulty. This also correlates with the statistics (cars using catalytic converters were introduced in 1986, corresponding with the increasing reduction of SIDS deaths that commenced from 1987).

Specifically on a link between SIDS and vaccination, studies have demonstrated that there is no increase in risk of SIDS in the 14 days following vaccination, and that the rate of SIDS is lower amongst the vaccinated population than the non-vaccinated. The Australian statistics on SIDS deaths show no increases at the usual times of vaccination. Although the highest risk for SIDS is in the period from 1-3 months of age, a breakdown of deaths by age show no difference at two months compared to one or three months (two months being the time of first vaccination).