French vegan baby dead (2008) https://www.theguardian.com/world/2011/mar/29/vegans-trial-d...
Belgian vegan baby dead (2014) http://www.bbc.com/news/world-europe-40274493
Italian vegan baby almost dies (2016) https://broadly.vice.com/en_us/article/4xkk3n/couple-lose-cu...
Another Italian vegan baby almost dies (2016) https://www.thelocal.it/20160629/two-year-old-in-serious-con...
Futhermore, malnutrition - divided into a)protein deficiency, which is the biggest component, and b)micronutrient deficiency - is globally the most important risk factor for illness and death. Over 19% of young children in India have a protein deficiency[1] and over 41% of young children in rural Nigeria[2]. It's obviously worse in undeveloped nations but check the dead babies above if you think it can't happen in the developed world too.
[1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4005205/ [2]https://www.ncbi.nlm.nih.gov/pubmed/10768411