What are the two broad categories that vaccines are classified into?

Vaccines are broadly classified into two main categories: live attenuated and inactivated vaccines. Live attenuated vaccines contain a weakened form of the pathogen that can still replicate but does not cause disease in a healthy individual. This type of vaccine can produce a strong and long-lasting immune response because it closely resembles a natural infection.

On the other hand, inactivated vaccines consist of pathogens that have been killed or inactivated so that they cannot replicate or cause disease. These vaccines typically require multiple doses to achieve adequate immunity, as they often generate a weaker response compared to live attenuated vaccines.

Understanding this classification helps in vaccine development and deployment, as each type has different implications for effectiveness, duration of immune response, and safety profiles. The other answer choices refer to more specific types or mechanisms of vaccines rather than the broad categories recognized in immunization practices.