With the rise of the COVID-19 vaccine, you may be wondering how exactly vaccinations work. How does a vaccine protect us against disease? The answer lies in an immune system response called active immunity. The immune system is a remarkably complex system that can build immunity against diseases – a response that a vaccine takes advantage of to reduce the incidence of specific diseases across a population.
Read on to find out everything you need to know about active immunity.
Overview of the Immune System
Before we dive into types of immunity and how vaccines work, let’s first go through a brief overview of the immune system. The immune system can be viewed as a defense mechanism that helps protect the body against infection and disease.
Many people don’t realize that the immune system starts with physical and biological barriers. The skin is the largest organ in the body and provides a protective layer that prevents the entry of infectious agents into the body. For example, mucus and hairs within the nose are designed to catch pathogens and prevent them from entering the respiratory system. These components of the immune system are considered to be part of innate immunity.
When these protective barriers fail to keep invaders out, the pathogen then comes in contact with other aspects of innate immunity. Innate immunity is a generalized immune response that attacks disease-causing pathogens. Components like macrophages produce cytokines that activate localized immune system activity to ward off infection.
When innate immunity doesn’t succeed in warding off the infectious agent, the adaptive immune response is activated. T cells and B cells, or lymphocytes, are the primary agents involved in the adaptive immune response.
Active vs Passive Immunity
In general, immunity can be split into two main types: active immunity and passive immunity. So, what’s the difference between active and passive immunity? Read on to find out.
Active Immunity
Active immunity is a type of adaptive immune response that occurs when your body is exposed to an invading pathogen. Any invading microbe that elicits an immune reaction is called an antigen. Viruses, bacteria, parasites, and fungi can function as antigens.
For example’s sake, let’s use the chickenpox virus. When we are exposed to the chickenpox virus, the immune system launches a response to try to kill the invading pathogen. Lymphocytes called B cells produce specific antibodies or immunoglobulins that are designed to kill off the chickenpox virus.
In the process, certain T-cells called memory cells essentially “remember” what the chickenpox virus looks like. At this point, the person has acquired natural immunity or natural active immunity. As a result, the next time a person is exposed to the chickenpox virus, the immune system is able to launch a speedier attack and prevent infection with the same virus.
Passive Immunity
In passive immunity, the person receives antibodies from an external source, instead of producing the antibodies themselves. For example, babies receive antibodies from their mother while in the womb, by way of the placenta. When babies are born, they often continue receiving antibodies through the mother’s breast milk. Breast milk produced during the first stages of infancy is referred to as colostrum and is rich in antibodies to help protect babies’ immune systems.
Some diseases may also be treated using antibody injections. For example, rabies can be treated with specific antibodies administered by injection.
How Vaccinations Use Active Immunity
As described above, the active immunity response can happen through natural exposure to a pathogen, generating natural immunity. Vaccination can also induce active immunity to a pathogen by exposing an individual to an inactive form of the virus. This way, a person’s immune system can produce specific antibodies and remember the antigen. In any future exposure to the antigen, the immune system can quickly produce the appropriate antibodies and take down the invading pathogen before infection sets in.
As babies and young children, many of us receive vaccinations from health care providers against dangerous diseases like mumps, measles, hepatitis, polio, diphtheria, whooping cough, and tetanus.
Many of us may also receive a yearly vaccination for strains of influenza, more commonly known as the flu. While the flu vaccine provides immunity against several common strains of influenza, the viral strains mutate, requiring a new flu vaccine each year.
The COVID-19 vaccines also take advantage of active immunity to protect individuals against infections caused by the novel coronavirus. According to the Centers for Disease Control and Protection (CDC), the COVID-19 vaccines work by administering viral genetic material in the form of mRNA, pieces of viral protein, or using viral vectors to trigger immunity. (1) When the body comes in contact with these parts of the coronavirus, memory cells form antibodies that can fight against the same virus in the future, resulting in specific immunity to the coronavirus pathogen. The body requires about 2 weeks to produce antibodies to the coronavirus.
When enough people in a population are vaccinated or possess memory cells for a certain pathogen, then this population is said to have reached herd immunity. Herd immunity has a protective effect on the entire population and essentially halts the spread of a particular infectious disease.
Tips for Supporting the Immune System
Now that we’ve gone through how the immune system works, what can we do to protect the immune system and keep it strong? Here are a few tips for supporting a healthy immune system that can fight disease efficiently.
1. Eat Enough Protein
Did you know that cytokines and antibodies are proteins? In order for your body to create these immune system agents, we need to ensure that we’re consuming an adequate amount of dietary protein on a daily basis. Moreover, protein provides the raw materials that the immune system needs to rebuild damaged skin, connective tissue, and muscle tissue.
All of these raw materials come from amino acids, which are the building blocks of proteins. When we ingest dietary protein, the body breaks down whole protein particles into amino acids. These amino acids are then used in a variety of biological processes, including muscle synthesis and the production of enzymes and proteins required in immune function.
Essential amino acids are particularly important for supporting biological functions. How can you ensure that you’re getting the essential amino acids you need each day? Lean meats, low-fat dairy, and fish are excellent sources of protein that offer optimal ratios of essential amino acids. A combination of vegetable proteins like nuts, seeds, beans, and soy products can also offer balanced ratios of essential amino acids for immune support. High-quality supplements can also help fill in dietary gaps in protein by offering optimal ratios of essential amino acids.
2. Vitamin C
You may have heard that vitamin C supports the immune system. But how does vitamin C work? Vitamin C is a micronutrient found in a variety of foods, including oranges, tomatoes, red bell peppers, sweet potatoes, and strawberries. Vitamin C operates as an antioxidant in the body, reducing cellular damage, reducing inflammation, and helping the immune system to work more effectively.
3. Vitamin D
Getting enough vitamin D is vital for boosting immune function and helping to prevent diseases of the immune system, including autoimmune conditions. A significant portion of the population likely has a vitamin D deficiency or insufficiency.
It can be challenging to get vitamin D from dietary sources since very few foods are rich in vitamin D. Mackerel and salmon are naturally high in vitamin D, and many dairy and cereal products have been enriched with vitamin D. Regular sun exposure also triggers vitamin D synthesis in the skin, though it’s important to moderate your level of sun exposure to minimize the risk of skin cancer. Supplementation is also a good option to ensure you’re getting the vitamin D you need for immune system support.
4. Balanced Diet and Exercise
In general, eating a balanced diet and living an active lifestyle support immune health and overall well-being. Strive to consume a diet that is primarily made up of whole foods, like fruits, vegetables, nuts, seeds, whole grains, lean meats, fish, and low-fat dairy. These foods provide the body and immune system with the nutrients they need to carry out all functions effectively. At the same time, keep your intake of processed foods, saturated fat, and added sugars at a minimum.
Combined with a healthy diet, engaging in regular aerobic exercise and strength training can also have positive effects on immune system health.
5. Handwashing and Mask Wearing
The immune support tips listed above focus on supporting the immune system from the inside. In addition, you can also support the external parts of the immune system by helping to prevent the invasion of pathogens in the first place. Our hands are the parts of the body
For illnesses like the flu and COVID-19, which transfer from person to person through respiratory particles, wearing a mask is vital for protecting yourself and others from viral spread.
Conclusion: What Is Active Immunity?
In summary, active immunity is an extremely important form of adaptive immunity in which the immune system becomes familiar with a certain pathogen and produces tailored antibodies to attack the invading particle. The immune system can then remember the pathogen and launch quick and effective attacks to prevent infection during any future exposure to the specific pathogen. Vaccinations take advantage of active immunity to protect us against diseases ranging from tetanus to COVID-19.
References:
(1) https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html
