Global health has been greatly impacted by vaccines. Smallpox, rinderpest, and several other major infections have been eradicated. A variety of infectious diseases of childhood have been significantly improved by whom in the past decade. As polio has been virtually eradicated, and measles has been controlled successfully, it may also be eradicated soon. Vaccines can prevent infections such as pneumonia and diarrhoea which cause 6.6 million deaths each year. Due to new pneumococcal conjugate vaccines and rotavirus vaccines, childhood mortality is expected to decline further. As of now, malaria, tuberculosis, and HIV vaccines have had modest success. Vaccinations that stimulate different immune systems and it may be the most effective way to prevent these infections. Reverse and structural vaccinology have revealed novel antigen candidates and molecular immunology has led to the formulation of promising adjuvants. Gene expression profiles and immune parameters in patients, vaccinees and healthy controls have formed the basis for biosignatures that will provide guidelines for future vaccine design. On a long-term basis, vaccines may prevent or modulate diseases other than infectious diseases. It is already possible to develop cancer vaccines, and in the future it will be possible to develop vaccines for addictions, diabetes, hypertension, and Alzheimer's disease as well. KEYWORDS: Vaccine. Technology, Immunity, Challenges, Regulatory.