Not all Vomiting and Diarrhea are due to viruses! Food Protein Induced Enterocolitis Syndrome (FPIES) is a cause to keep on your Ddx for infants with severe vomiting and diarrhea.
Vitamins are important! Specific restrictive diets may adversely affect a child's ability to meet dietary requirements. Let's review what you need to consider with Vegan Diets in Children.