One of the ways your immune system fights off infection is by creating large proteins known as antibodies. These antibodies act as scouts, hunting down the infectious agent, and marking it for destruction by the immune system. Each antibody is specific to the bacteria or virus that it has detected and will trigger a specific immune response. These specific antibodies will remain in the immune system after the infection has gone.
Vaccination is the safest and most common way to gain immunity against a bacteria or virus that your body has yet to encounter. Vaccines contain a harmless form of the bacteria or virus that causes the disease you are being immunised against. The bacteria or virus will be killed, greatly weakened, or broken down into small parts before use in the vaccine so that they can trigger an immune response without making you sick.
Your immune system will still attack the harmless form of bacteria or virus from the vaccine and will produce antibodies to fight it off. The immune system then keeps a memory of the disease, so if a vaccinated person encounters the disease years later, their immune system is ready to fight it off and prevent an infection from developing.
The only way to get the disease naturally would be through infection with the bacteria or virus that causes the disease. Some diseases, such as measles and meningitis, can also be fatal. Natural infection also enables the disease to spread from your child to those around them, increasing the risk of others getting ill. Vaccination allows your child to build up immunity in a safe and controlled environment without becoming ill with the disease and passing it to others.
Looking at the history of vaccine-preventable disease, there is a huge drop in the number of cases of a disease following the introduction of a vaccine against it.
If smallpox had not been eradicated, it would cause 5 million deaths worldwide a year! Blood contains red blood cells, for carrying oxygen to tissues and organs, and white or immune cells, for fighting infection. These white cells consist primarily of macrophages, B-lymphocytes and T-lymphocytes:. Vaccines prevent diseases that can be dangerous, or even deadly.
This fact sheet explains how the body fights infection and how vaccines work to protect people by producing immunity. 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 antigens are detected, B-lymphocytes produce antibodies to attack them. 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.
Sometimes, after getting a vaccine, the imitation infection can cause minor symptoms, such as fever. Such minor symptoms are normal and should be expected as the body builds immunity. However, 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.
Scientists take many approaches to developing vaccines. These approaches are based on information about the infections caused by viruses or bacteria the vaccine will prevent, such as how germs infect cells and how the immune system responds to it. Practical considerations, such as regions of the world where the vaccine would be used, are also important because the strain of a virus and environmental conditions, such as temperature and risk of exposure, may be different across the globe.
The vaccine delivery options available may also differ geographically. Today there are five main types of vaccines that infants and young children commonly receive in the U.
There are four reasons that babies—and even teens or adults—who receive a vaccine for the first time may need more than one dose:. Some people believe that naturally acquired immunity—immunity from having the disease itself—is better than the immunity provided by vaccines. However, natural infections can cause severe complications and be deadly.
This is true even for diseases that many people consider mild, like chickenpox. It is impossible to predict who will get serious infections that may lead to hospitalization. In essence, scientists are able to take a harmless pathogen, dress it in the DNA of a more dangerous disease, and train the body to recognize and fight both effectively.
The Herd Immunity Imperative Vaccines don't just work on an individual level, they protect entire populations. Featured Online Programs This is critical because there will always be a percentage of the population that cannot be vaccinated, including infants, young children, the elderly, people with severe allergies, pregnant women, or people with compromised immune systems.
Types of Vaccines The key to vaccines is injecting the antigens into the body without causing the person to get sick at the same time. Advantages: Because these vaccines introduce actual live pathogens into the body, it is an excellent simulation for the immune system. So live attenuated vaccines can result in lifelong immunity with just one or two doses.
Disadvantages: Because they contain living pathogens, live attenuated vaccines are not given to people with weakened immune systems, such as people undergoing chemotherapy or HIV treatment, as there is a risk the pathogen could get stronger and cause sickness. Additionally, these vaccines must be refrigerated at all times so the weakened pathogen doesn't die.
Specific Vaccines: Measles Mumps Rubella MMR combined vaccine Varicella chickenpox Influenza nasal spray Rotavirus Inactivated Vaccines: For these vaccines, the specific virus or bacteria is killed with heat or chemicals, and its dead cells are introduced into the body. Advantages: These vaccines can be freeze dried and easily stored because there is no risk of killing the pathogen as there is with live attenuated vaccines.
They are also safer, without the risk of the virus or bacteria mutating back into its disease-causing form. Disadvantages: Because the virus or bacteria is dead, it's not as accurate a simulation of the real thing as a live attenuated virus.
Therefore, it often takes several doses and "booster shots" to train the body to defend itself. Advantages: With these vaccines, the chance of an adverse reaction in the patient is much lower, because only a part or the original pathogen is injected into the body instead of the whole thing. The very low risk of an adverse event caused by a vaccine greatly outweighs the risk Risk The probability that an individual will experience a certain event during a defined period of time.
The following pages will discuss in further detail the attributes of vaccines and the characteristic causes for adverse events. How vaccines work Key point Vaccines stimulate the immune system to develop long-lasting immunity against antigens from specific pathogens.
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