Vaccine efficacy is evaluated through clinical trials that assess the vaccine's ability to prevent disease in a controlled setting. These trials typically involve multiple phases:
Phase I: Small-scale trials to assess safety and immune response. Phase II: Larger trials to evaluate the optimal dose and further assess safety and immunogenicity. Phase III: Large-scale trials to determine efficacy and monitor adverse effects.
Post-marketing surveillance continues to monitor the vaccine's safety and effectiveness in the general population.
