evidence: Vaccine Ingredients: Corn and Peanut Oils "My daughter has a corn allergy, do I need to worry about her getting vaccines?" "I heard the rise in peanut allergies is because peanut oils are used in vaccines. Is this true?" Both of these questions are related to the notion that oils in vaccines can cause allergic reactions in those who have food sensitivities. Indeed, if someone has a sensitivity to a vaccine component, they may be advised not to get it; however, vaccines do not contain either corn or peanut oils.