• Orphan Vaccine Concept: An orphan vaccine is a biologically effective, proven vaccine that targets a neglected or commercially unviable disease condition, resulting in lack of commercial production and distribution.
• Case of To45W Vaccine: The To45W recombinant oncosphere antigen vaccine was developed to protect sheep against Taenia ovis metacestodes (sheep measles). While conferring $\gt 95\%$ protection against cysticercosis, T. ovis causes aesthetic carcass condemnation without acute clinical mortality or human health threat, so pharmaceutical companies ceased commercial production, classifying it as an orphan vaccine.
• Contrast with Commercial Vaccines: Rakshavac-T (Theileria annulata), Dictol (Dictyocaulus viviparus irradiated lungworm vaccine), and Paracox (Eimeria spp.) have established commercial markets.

Correct option: (1) To45W based vaccine