poliomyelitis vaccine
The polio vaccine prevents infections form the virus poliomyelitis.
Viruses
Viruses are microorganism that can only replicate if they are inside a host cell. They consist of genetic material (DNA or RNA) wrapped in a protein capsule.
Viruses can't reproduce (replicate itself) without a host. When viruses find a host, we say that the host is infected with the virus. Once it has a host it uses the host's cells to replicate its genetic material and replicate itself.
If you've ever had the flu or chicken pox, then you've been a host for a virus!
Viruses are spread by a carrier that can infect other organisms. The carrier can be water, air or even other animals.
How does it work?
Your immune system is a complex system that protects your body from pathogens. A key player is your white blood cells (which are made in your bone marrow). White blood cells travel around in your body in the blood searching for pathogens such as the poliomyelitis virus. When they find one, they start an attack and the body tries to kill the invader. Both fever and inflammation are part of the innate immune response to all pathogens.
As well as your innate immune system, you also have an adaptive immune system. This system searches for and remembers how to kill particular pathogens. White blood cells that are part of the adaptive immune system identify particular pathogens by recognising the unique proteins or lipids on the surface of the cell membrane of the invader, called antigens. White blood cells store this information on the outside of their own cell, in the form of proteins called antibodies. Antibodies bind to the specific pathogen's antigens because antigen is complementary to the antibodies. When an antibody binds to the complementary antigens, the pathogen is tagged, thus signalling to immune cells (like killer T cells) to destroy the pathogen.
Vaccines are used to stimulate your adaptive immune system. They aim to cause your body to produce the specific antibodies that recognise the pathogen the vaccine has been made for. A vaccine introduces the pathogen (or parts of the pathogen) to our immune system so that our antibodies learn how to recognise it and our bodies learn how to fight it. The next time our immune system sees the pathogen, it will be able to quickly recognise it and know how to fight it preventing us from getting sick.
Did you know: Because vaccines effect our immune systems we call getting a vaccine immunisation.
Herd Immunity
For many reasons, some people can not be vaccinated. This may include health issues, religious and cultural issues or the government may not have approved a vaccine for certain people such as children. Unfortunately, this means these people are at risk of infections but it can be reduce through herd immunity.
Herd immunity is achieved when a majority of the population is vaccinated. Those vaccinated are less likely to become infected with the virus and thus less likely to pass it on to others. This lowers the amount of virus in the community, protecting those people who can not be vaccinated. Thanks to a dedicated mass vaccination effort, poliomyelitis infections have drastically reduced worldwide!