#5 Neomycin Sulphate [antibiotic]
Interferes with vitamin B6 absorption which can lead to epilepsy and brain damage. Allergic reactions can range from mild to life -threatening.
Many vaccines contain trace amounts of neomycin to prevent bacterial contamination during the manufacturing process. As a topical medicament, neomycin elicits a high sensitization rate. According to the NACDG, neomycin is the third most prevalent allergen that often manifests as a delayed-type contact dermatitis. Source