inactivated vaccine

An inactivated vaccine contains a virus or bacteria that has been killed or inactivated so it cannot cause disease. When you receive this vaccine, your immune system recognizes the harmless part of the pathogen and learns to attack it. This prepares your body to fight the real virus or bacteria if you're exposed in the future. Because the pathogen is dead, inactivated vaccines are very safe and suitable for most people, including those with weakened immune systems. Examples include the flu shot and hepatitis A vaccine. They typically require multiple doses to maintain protection.