Jeev 3mcg Vaccine is an immunobiological preparation containing 3 micrograms of inactivated Japanese Encephalitis virus protein per dose. It is indicated for active immunization against Japanese Encephalitis (JE), a mosquito-borne viral infection prevalent in endemic regions of Asia and the Western Pacific. The vaccine stimulates the immune system to produce protective antibodies, thereby reducing the risk of JE virus infection and its associated neurological complications. Jeev 3mcg Vaccine is administered intramuscularly, typically in a two-dose schedule spaced 28 days apart, with a booster dose recommended depending on ongoing risk exposure and local health guidelines. The vaccine is contraindicated in individuals with known hypersensitivity to any component of the formulation. Common adverse reactions are generally mild and transient, including injection site pain, erythema, and low-grade fever. Serious adverse events are rare. Immunization with Jeev 3mcg Vaccine is a critical preventive measure for travelers to endemic areas and residents in high-risk zones, contributing significantly to the reduction of JE incidence and morbidity. Healthcare providers should evaluate patient history and potential contraindications prior to administration and report any adverse events following immunization to appropriate pharmacovigilance authorities.