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The human race is born quite helpless and has a lot to learn. Just as you have to learn how to walk, your immune system must also learn how to protect against infection. Your immune system develops over time, just as you progress from crawling to standing, running, and walking.
Scientists study the immune responses to vaccines in different age groups. This is why vaccines such as COVID-19 need to be tested in separate children between ages 5-11 and ages 12-16. Doctors aim to provide the most protection and minimize side effects. It all depends on how well the immune system works. This is something you can't see from the outside.
As an immunologist, this is how I explain vaccines to adults and children of different ages.
The immune system is made up of two halves
Soon after birth, the immune maturing process begins.
Your mother's antibodies and your mother's breast milk provide your primary immune protection when you are born. These antibodies provide passive immunity. The adaptive immune system of newborns, the part that makes your own antibodies, isn't yet fully functional. Although the process can be initiated immediately, it may take several years before your adaptive immune system reaches full maturity.
Your innate immune system, which is what you were born with, lasts your entire life. The adaptive immune system doesn't have to be taught to protect against infections and promote good health. People would be more likely to get sick without the innate immune system.
Your skin and mucous membranes are the first place your innate immune system begins. If germs manage to get past these physical barriers, there are enzymes that can help break down foreign organisms. There are also specialized cells that look for intruders to be killed. Other cells, called phagocytes, eat invaders.
Your body's first response is the innate immune system. It saves you some time. Your adaptive immune system joins the fray and helps you fight.
Your adaptive immune system makes antibodies when you are immunized against a virus or an infection. These proteins act as suction cups and stick with bacteria and viruses to aid the body eliminate the germs quicker and stop the infection spreading. Antibodies can be used to identify and eliminate a specific intruder.
The adaptive immune system is able to learn new infections or recall an infection it hasn't seen in a while.
Vaccines account for immune development
The same way that an infant learns to walk, even if there are no stairways or pool areas to help them, so your immune system can learn how to stop an invading disease without the need for a vaccine. However, the risk of injury is greater.
Vaccines trigger the production of antibodies that recognize specific germs and fight them off. This is safer than getting infected the first time. The effectiveness of a vaccine depends on how many antibodies are produced in response and how safe they are.
Researchers must be aware of which parts of the immune system are active and offline in order to adjust the dose of vaccines for different ages. This is why vaccines such as COVID-19are approved and tested on different schedules.
Infants receive a number of vaccines in a series. This means that they are given the same shot multiple times over a period of time. Baby's adaptive immune system can become forgetful and not listen at this stage. This is the same age that a baby struggles to stand or walk. Every exposure to infection makes the immune system stronger and more effective at fighting off the potential infection.
Your immune system becomes more responsive after 4 years and less likely to forget. This is the time when most people develop allergies. Researchers at Pfizer discovered that children aged 5-11 had an identical immune response to the COVID-19 vaccine. This was one-third of the dose given to those 12 years and older.
When studying vaccines, scientists tend to work with patients aged between 18 and 55. Because their adult immune systems are matured, they can report adverse reactions reliably. Physicians can also use this information to predict the effects of vaccines on others.
The adaptive immune system begins to decline around age 55 and becomes less efficient. These older patients can get a quick boost with vaccine boosters. They can be protected from falls even after they have mastered running and walking for a long time.
Vaccines are the best environment for the immune system's learning. Adjusting dosages for different ages helps to ensure that every patient receives the right dose.
This article was first published by The Conversation. You can read the original article.
