Vaccines are a “training course” of the human immune system. They prepare the body to fight a specific disease without being exposed to the disease symptoms. Vaccines are a way to stimulate our immune system to simulate disease without ill. Immunizations are administered either by injection (subcutaneous or intramuscular), or – in the form of drops – orally.
When foreign invaders such as bacteria or viruses enter the body, immune cells called lymphocytes react by producing antibodies that are actually protein molecules. These “antibodies” to fight the invaders, called “antigen” and protect the body against further infection.
Healthy person can produce millions of antibodies per day and fight infections is so efficient that one can not understand that at some point his body was exposed to antigens.
When I first body faces particular invader, it can take several days to create in response to their guards – antibodies. For really nasty antigens as measles or whooping cough bacteria, a few days is too long. The infection can spread and kill a man before his immune system could fight back.
And here appears the vaccine. The vaccine is a biological preparation, dead or attenuated antigens, which enhances the ability of the immune system to combat a particular disease. The agent of the vaccine stimulates the body’s immune system recognizes it as a foreign body to destroy it, and remember to be able to more easily recognize and destroy microorganisms that cause the disease in the event of a later confrontation with him.
http://nauka.bg/sites/default/files/field/image/diphtheria1.jpgАнтигените, contained in the vaccine can not cause infection, but the immune system still views them as enemies and begins to produce antibodies response to the false attack. Once the threat passes, many antibodies will prove to be defeated, but the body will remain immune cells called “memory cells”. When the body gets back cognate antigen memory cells produce antibodies quickly, which destroy the invader before it is too late.
Vaccines can work with the “community.” Some people can not be vaccinated or because they are too young, or – because their immune system is too weak. But if all the other people around them have been vaccinated, unvaccinated people are protected by the so-called. “Collective immunity”. In other words, they are unlikely to come into contact with the disease, so that probably will not get sick. When it comes to vaccination, sometimes it is not bad to follow the crowd.