Challenge vaccine

A challenge vaccine is a type of vaccine used primarily in research to test immunity. After vaccination, the person (or animal) is deliberately exposed to the disease-causing organism in a controlled setting. If the immune system successfully fights it off, it indicates the vaccine has provided protection. This method helps scientists evaluate how effective a vaccine is before it is widely used. Challenge studies are carefully regulated to ensure safety and are conducted under strict ethical guidelines, mainly in research settings rather than routine vaccination programs.