Pathogen resistance, particularly in the context of vaccines, is a growing concern as certain pathogens evolve mechanisms to evade immune responses. Resistance may result from mutations in the pathogen’s structure, altering the effectiveness of the vaccine. Continuous monitoring and adaptation of vaccines are essential to counteract these mutations and sustain efficacy. Researchers are now using genomic surveillance to track pathogen evolution, ensuring that vaccines can be modified as needed. Advances in vaccine design, such as multi-strain and mRNA-based vaccines, are enabling more flexible responses to resistance, helping maintain vaccine effectiveness in an ever-changing microbial landscape.