Vaccines and Immunization

Vaccine Safety & Efficacy

Vaccine efficacy refers to the ability of vaccines to bring about the intended beneficial effects on vaccinated individuals in a defined population under ideal conditions of use. The potential benefits of an effective vaccine  e.g. promotion of health and well-being, and protection from illness and its physical, psychological and socioeconomic consequences must be weighed against the potential risk of an adverse event following immunization (AEFI) with that vaccine. Vaccine-associated risk is the probability of an adverse or unwanted outcome occurring, and the severity of the resulting harm to the health of vaccinated individuals in a defined population following immunization with a vaccine under ideal conditions of use.