Question

What is the role of vaccines in the body?

Answer 1

A vaccine is a biological preparation that induces active acquired immunity against a specific infectious disease. A vaccine usually contains an agent that looks like a disease-causing microorganism and is often made from weakened or killed versions of the microbe, its toxins, or one of its surface proteins.

Complete answer:
The body has numerous defence mechanisms against pathogens (disease-causing organisms). Pathogens are kept out of the body by physical barriers such as skin, mucus, and cilia tiny hairs that carry material away from the lungs. When a pathogen infects the body, our body's defences, known as the immune system, are activated, and the pathogen is attacked and destroyed.

A pathogen is a microorganism such as a bacterium, virus, parasite, or fungus that can cause disease in the body. Each pathogen is composed of several subparts, each of which is unique to that pathogen and the disease it causes. An antigen is the component of a pathogen that causes the formation of antibodies. Antibodies produced in response to pathogen antigens are an important component of the immune system.

Antibodies can be thought of as soldiers in your body's defence system. Each antibody, or soldier, in our system, has been programmed to recognise a single antigen. Our bodies contain thousands of different antibodies. Physical barriers such as skin, mucus, and cilia, microscopic hairs that move material away from the lungs, keep pathogens out of the body.

Vaccines contain weakened or inactive parts of a specific organism (antigen), which causes an immune response in the body. The blueprint for producing antigens, rather than the antigen itself, is contained in newer vaccines. Whether the vaccine is made up of the antigen itself or the blueprint for the body to produce the antigen, this weakened version will not cause the disease in the person receiving the vaccine, but it will prompt their immune system to respond in the same way that it would have in its first reaction to the actual pathogen.

Some vaccines necessitate multiple doses administered weeks or months apart. This is occasionally required to allow for the production of long-lasting antibodies and the development of memory cells. In this way, the body is trained to fight the specific disease-causing organism, storing pathogen memory so that it can fight it quickly if and when it is exposed in the future.

When a person is immunised, they are almost certainly protected against the targeted disease. However, not everyone can be immunised. People who have underlying health conditions that weaken their immune systems (such as cancer or HIV) or who have severe allergies to certain vaccine components may be unable to receive certain vaccines. These individuals can still be protected if they reside in and amongst others who are vaccinated.

When a large number of people in a community are immunised, the pathogen has a difficult time spreading because most of the people it encounters are immune. As a result, the more people who are vaccinated, the less likely it is that people who are unable to be protected by vaccines will be exposed to harmful pathogens. This is known as herd immunity.

Note: Polio was a worldwide disease in the early 1900s, paralysing hundreds of thousands of people each year. Two effective vaccines against the disease had been developed by 1950. However, vaccination was still not widespread enough in some parts of the world to prevent the spread of polio, particularly in Africa. In the 1980s, a concerted global effort to eradicate polio began.