How do vaccines primarily protect against diseases?

Vaccines primarily offer protection against diseases by stimulating the immune system to produce antibodies. When a vaccine is administered, it contains a harmless component of a virus or bacterium, such as a protein or an inactivated or weakened form of the pathogen. This exposure allows the immune system to recognize and respond to the pathogen as if it were a real infection.

As a result, the immune system activates and generates specific antibodies that target that particular pathogen. It also generates memory cells that "remember" how to respond to the pathogen in the future. This means that if a vaccinated individual later encounters the actual disease-causing pathogen, their immune system can quickly recognize and neutralize it, preventing illness or reducing the severity of the disease.

This process underscores the effectiveness of vaccines in preventing infectious diseases, as they train the body’s immune defenses without causing the disease itself.