Vaccine is a medical preparation intended to create immunity to infectious diseases. Vaccine is made from weakened or killed microorganisms, products of their vital activity, or from their antigens obtained by genetic engineering or chemical means.
Principles of vaccination:
- Vaccination stimulates the adaptive immune response, forming specific memory cells in the body. The subsequent infection by the same agent causes a persistent, faster immune response;
- Vaccines should be safe and affordable.
Live vaccines are made on the basis of weakened strains of a microorganism with persistently fixed avirulence (harmlessness). The vaccine strain, after administration, multiplies in the body of the vaccinated and causes a vaccinal infectious process. In most vaccinated patients, the vaccine infection occurs without significant clinical symptoms and leads to the formation, as a rule, of persistent immunity. Vaccines for the prevention of rubella, measles, poliomyelitis, tuberculosis, mumps can serve as an example of live vaccines.
Corpuscular vaccines contain weakened or killed microbes (virions).
They are created from antigenic components extracted from a microbial cell. They isolate those antigens that determine the immunogenic characteristics of the microorganism.
These vaccines are produced by using genetic engineering methods, integrating the genetic material of the microorganism into yeast cells that produce antigen. After cultivation of yeast, the necessary antigen is isolated, purified and the vaccine is prepared. An example of such vaccines is a vaccine against hepatitis B or a vaccine against human papillomavirus (HPV).