It may not be conclusively proved, but the evidence linking vaccines and Sudden Infant Death Syndrome deserves serious study. From Steve Kirsch at stevekirsch.substack.com:
Even the CDC admits that vaccines can cause serious brain injury and death. Is it any surprise that vaccines can cause sudden infant deaths too?

Coincidence? No single case can PROVE causality. It’s the sheer number of these results and the statistical odds ratios that make the case, plus biological plausibility.
Executive summary
In this article, I’ll present just a few simple examples that demonstrate that vaccines cause autism. If vaccines don’t cause autism, these data points are hard to explain away. And note that “they” never show you their data points measuring the same thing that show an opposite result!!
Stop or delay vaccination —> SIDS decreases dramatically
If you stop vaccinating, or simply delay when vaccines are given to kids, the rate of SIDS goes down. See this article.
There’s that sudden(ly) again.