vaccin

Vaccin is the term used in several languages, including French, to refer to a preparation that stimulates the body's immune system to provide protection against a specific disease. Vaccins are designed to expose the immune system to a safe form of a pathogen or its components, teaching it to recognize and respond effectively to real infections.

Vaccins come in various types, including live-attenuated vaccines, inactivated vaccines, subunit and protein-based vaccines, toxoid vaccines, conjugate vaccines, and nucleic acid vaccines such as mRNA vaccines. Some vaccines use harmless parts of a pathogen, while others deliver genetic instructions or non-infectious particles that prompt an immune response without causing disease.

Historically, vaccinology began with the smallpox work of Edward Jenner in the late 18th century and evolved through advances in microbiology and immunology. Modern vaccinology emphasizes safety, efficacy, and the ability to induce durable protection. Vaccin development follows strict preclinical testing, phased clinical trials (I–III), regulatory review, and post-licensure surveillance for adverse events. Storage, handling, and cold chain requirements are essential to maintain potency from production to administration.

Vaccins have had a profound impact on public health, reducing or eradicating numerous diseases and contributing to herd immunity when uptake is high. Challenges include equitable global access, vaccine hesitancy, misinformation, and the need for continual monitoring of safety and effectiveness. International organizations and programs, such as the World Health Organization and Gavi, work to expand coverage and respond to emerging infectious threats.