How do live attenuated vaccines differ from inactivated vaccines?

Live attenuated vaccines contain weakened forms of the pathogen, which means that they are made from live microbes that have been altered so they cannot cause disease in healthy individuals. This weakened state allows the immune system to recognize and respond to the pathogen without the risk of causing the disease itself. The body's immune response to a live attenuated vaccine tends to be strong and long-lasting because the immune system can recognize the live but weakened pathogen as if it were the actual disease.

In contrast, inactivated vaccines contain pathogens that have been killed or inactivated so they cannot replicate or cause disease. While inactivated vaccines can effectively stimulate an immune response, they might require booster doses to maintain immunity since they generally do not provide as robust or long-lasting immune responses as live attenuated vaccines can.

Understanding these differences helps clarify why certain vaccines are chosen for specific immunization schedules and public health strategies. Live attenuated vaccines often provide stronger immunity with fewer doses, compared to inactivated vaccines, which sometimes necessitate multiple doses to achieve the desired immune response.