How do Vaccinations Work?
HOW DO VACCINATIONS WORK: THE IMMUNE SYSTEM
When germs, such as bacteria or viruses invade our body, they can multiple and will attack our system and this invasion is known as infection. To put it in simple words, when the body realises that there’s some type of unknown organism within our system, the blood sends white or immune cells to fight the infection. These white cells consist primarily of macrophages, B-lymphocytes, and T-lymphocytes.
Macrophages – are white blood cells that swallow up and digest germs, plus dead or dying cells. The macrophages leave behind parts of the invading germs called antigens. Then the body identifies antigens as dangerous and stimulates antibodies to attack them.
B-lymphocytes – are defensive white blood cells. They produce antibodies that attack the antigens left behind by the macrophages.
T-lymphocytes – are another type of defensive white blood cell. They attack cells in the body that have already been infected.
The first time the body encounters a germ, it can take several days to make and use all the germ-fighting tools needed to get over the infection. After the infection, the immune system remembers what it learned about how to protect the body against that disease. The body keeps a few T-lymphocytes, called memory cells, that go into action quickly if the body encounters the same germ again. When the familiar organisms are detected, B-lymphocytes produce antibodies to attack them.
Unfortunately, bad germs and bacteria are all around us and when a susceptible person encounters a harmful organism, it can lead to disease and death. These harmful organisms are called pathogens, organisms that can cause diseases and/or illnesses.
HOW DO VACCINATIONS WORK: ANTIGENS AND PATHOGENS
The body has many ways of defending itself against pathogens. It uses the skin, mucus, and cilia (microscopic hairs that move debris away from the lungs) that works together as physical barriers to prevent pathogens from entering the body in the first place. Each pathogen is made up of several subparts, usually unique to that specific pathogen and the disease it causes. The subpart of a pathogen that causes the formation of antibodies is called an antigen, molecules that trigger an immune response. The antibodies produced in response to the pathogen’s antigen are an important part of the immune system. Likewise, each antibody in our system is trained to recognize one specific antigen.
However, as said before, this process of fighting an unknown organism can take several days as the body needs time to respond and produce specific antibodies to that antigen. And in the meantime, the person is susceptible to become ill. So how do vaccinations work? They are crucial to help prevent us from getting serious diseases that can cause long-term health problems or even be deadly.
HOW DO VACCINATIONS WORK?
Vaccines help develop immunity by imitating an infection. This type of infection, however, almost never causes illness, but it does cause the immune system to produce T-lymphocytes and antibodies. In other words, vaccines contain weakened or inactive parts of a particular organism (antigen) that triggers an immune response within the body. Newer vaccines contain the blueprint for producing antigens rather than the antigen itself. Regardless of whether the vaccine is made up of the antigen itself or the blueprint so that the body will 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 much as it would have on its first reaction to the actual pathogen.
Sometimes, after getting a vaccine, imitation infection can cause minor symptoms, such as fever. Such minor symptoms are normal and should be expected as the body builds immunity. Also, it typically takes a few weeks for the body to produce T-lymphocytes and B-lymphocytes after vaccination. Therefore, it is possible that a person infected with a disease just before or just after vaccination could develop symptoms and get a disease because the vaccine has not had enough time to provide protection.
Some vaccines require multiple doses, given weeks or months apart. This is sometimes needed to allow to the production of long-lived antibodies and the development of memory cells. In this way, the body is trained to fight the specific disease-causing organism, building up memory of the pathogen to rapidly fight it when exposed in the future.
HOW DO VACCINATIONS WORK: A NOTE
People with underlying health conditions that weaken their immune systems, such as cancer or HIV, or people who have several allergies to some of the vaccine components might not be able to get the vaccine. However, those people still can be protected if they live in a vaccinated community. This because if people are vaccinated, they are immune to the pathogen and therefore can’t pass the virus to other people. All this process is called herd immunity.
HOW DO VACCINATIONS WORK: A FUN FACT ABOUT DIFFERENT TYPES OF VACCINES
Live, attenuated vaccines fight viruses and bacteria. These vaccines contain a version of the living virus or bacteria that have been weakened so that it does not cause serious disease in people with healthy immune systems. Examples of live, attenuated vaccines include measles, mumps, and rubella vaccine (MMR) and varicella (chickenpox) vaccine. However, even though they are very effective, not everyone can receive these vaccines. Children with weakened immune systems, for example, those who are undergoing chemotherapy can’t get live vaccines.
Inactivated vaccines also fight viruses and bacteria. These vaccines are made by inactivating, or killing, the germ during the process of making the vaccine. The inactivated polio vaccine is an example of this type of vaccine. Inactivated vaccines produce immune responses in different ways than live, attenuated vaccines. Often, multiple doses are necessary to build up and/or maintain immunity.
Toxoid vaccines prevent diseases caused by bacteria that produce toxins (poisons) in the body. In the process of making these vaccines, the toxins are weakened so they can’t cause illness. Weakened toxins are called toxoids. When the immune system receives a vaccine containing a toxoid, it learns how to fight off the natural toxin. The DTaP vaccine contains diphtheria and tetanus toxoids.
Subunit vaccines include only parts of the virus or bacteria, or subunits, instead of the entire germ. Because these vaccines contain only the essential antigens and not all the other molecules that make up the germ, side effects are less common. Pertussis (whooping cough) component of the DTaP vaccine is an example of a subunit vaccine.
Conjugate vaccines fight different type of bacteria. These bacteria have antigens with an outer coating of sugar-like substances called polysaccharides. This type of coating disguises the antigen, making it hard for a young child’s immature immune system to recognize it and respond to it. Conjugate vaccines are effective for these types of bacteria because they connect (or conjugate) the polysaccharides to antigens that the immune system responds to very well. This linkage helps the immature immune system react to the coating and develop an immune response. An example of this type of vaccine is the Haemophilus influenzae type B (Hib) vaccine.
Now that you have the question to how do vaccinations work, you can check here to see what vaccinations children need.
