How does the Immune system work?
The immune system has a vital role: It protects your body from harmful substances, germs and cell changes that could make you ill. It is made up of various organs, cells and proteins.
As long as your immune system is running smoothly, you don’t notice that it’s there. But if it stops working properly – because it’s weak or can’t fight particularly aggressive germs – you get ill.
Germs that your body has never encountered before are also likely to make you ill. Some germs will only make you ill the first time you come into contact with them. These include childhood diseases like chickenpox.
The tasks of the immune system
Without an immune system, we would have no way to fight harmful things that enter our body from the outside or harmful changes that occur inside our body. The main tasks of the body’s immune system are
- to fight disease-causing germs (pathogens) like bacteria, viruses, parasites or fungi, and to remove them from the body,
- to recognize and neutralize harmful substances from the environment, and
- to fight disease-causing changes in the body, such as cancer cells.
How is the immune system activated?
The immune system can be activated by a lot of different things that the body doesn’t recognize as its own. These are called antigens.
Examples of antigens include the proteins on the surfaces of bacteria, fungi and viruses. When these antigens attach to special receptors on the immune cells (immune system cells), a whole series of processes are triggered in the body.
Once the body has come into contact with a disease-causing germ for the first time, it usually stores information about the germ and how to fight it. Then, if it comes into contact with the germ again, it recognizes the germ straight away and can start fighting it faster.
The body’s own cells have proteins on their surface, too. But those proteins don’t usually trigger the immune system to fight the cells. Sometimes the immune system mistakenly thinks that the body’s own cells are foreign cells. It then attacks healthy, harmless cells in the body. This is known as an autoimmune response.
Innate and adaptive immune system
There are two subsystems within the immune system, known as the innate (non-specific) immune system and the adaptive (specific) immune system. Both of these subsystems are closely linked and work together whenever a germ or harmful substance triggers an immune response.
The innate immune system provides a general defense against harmful germs and substances, so it’s also called the non-specific immune system. It mostly fights using immune cells such as natural killer cells and phagocytes (“eating cells”).
The main job of the innate immune system is to fight harmful substances and germs that enter the body, for instance through the skin or digestive system.
The adaptive (specific) immune system makes antibodies and uses them to specifically fight certain germs that the body has previously come into contact with. This is also known as an “acquired” (learned) or specific immune response.
Because the adaptive immune system is constantly learning and adapting, the body can also fight bacteria or viruses that change over time.
What Does It Mean to Be Immunocompromised?
Think of your immune system as a strong army. Its mission? To protect you from enemies both foreign (viruses and bacteria) and domestic (diseases like cancer).
But when you’re immunocompromised, your immune system’s defenses are low, affecting its ability to fight off infections and diseases.
Depending on why your immune system is compromised, this state can be either permanent or temporary.
1. Chronic diseases
Certain conditions, such as HIV and AIDS, destroy immune cells, leaving your body vulnerable to other attacks. Autoimmune conditions turn immune cells into double agents that fight against your own healthy tissues. Common autoimmune diseases include:
- Lupus
- Rheumatoid arthritis
- Type 1 diabetes
Even well-controlled diabetics are immunocompromised to a degree. Simply having an infection can also raise blood sugars and give rise to additional infections. And immunity can get disrupted by high blood sugars. It’s a circular problem.
Conditions like asthma can also affect your immune system because they cause it to dangerously overreact to harmless substances.
Leukaemia or lymphoma are also diseases of the immune system. They are white blood cell diseases, and white blood cells are needed to respond to infections.
2. Medical treatments
Some cancer treatments weaken your immune system as they destroy cancer cells. And if you have an autoimmune disease, a suppressed immune system is the desired result.
Since a patient’s own immune system is revved up and attacking various parts of the body, the treatments for autoimmune diseases are often medicines designed to weaken the immune system.
This process may spell double-trouble, as it could make you more prone to getting COVID-19 and put you at higher risk for severe illness. It may also limit your body’s ability to make antibodies that could be needed to clear the infection.
3. Organ or bone marrow transplant
You’re more susceptible to infection in the first weeks after a bone marrow transplant because you don’t have many white blood cells.
If you’ve had an organ or bone marrow transplant, you also need to continue to take medication to suppress your immune system.
These kinds of medications, also known as anti-rejection drugs and immune suppressants, help your body accept the new cells and prevent the new immune cells from attacking your normal tissues.
4. Age
People can develop underlying conditions or medical problems as they get older,” Dr. Porter says. “And sometimes, their immune system doesn’t respond normally to infections because it doesn’t work as well as a younger person’s. Therefore, they may get sicker when they have the flu or COVID-19.
5. Smoking
People who are smokers tend to get sicker from infections, It may be that smoking impacts the immune system’s ability to respond appropriately.
How do vaccines work?
Germs are all around us, both in our environment and in our bodies. When a person is susceptible and they encounter a harmful organism, it can lead to disease and death.
The body has many ways of defending itself against pathogens (disease-causing organisms). Skin, mucus, and cilia (microscopic hairs that move debris away from the lungs) all work as physical barriers to prevent pathogens from entering the body in the first place.
When a pathogen does infect the body, our body’s defences, called the immune system, are triggered and the pathogen is attacked and destroyed or overcome.
The body’s natural response
A pathogen is a bacterium, virus, parasite or fungus that can cause disease within the body. 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. The antibodies produced in response to the pathogen’s antigen are an important part of the immune system.
You can consider antibodies as the soldiers in your body’s defense system. Each antibody, or soldier, in our system is trained to recognize one specific antigen. We have thousands of different antibodies in our bodies.
When the human body is exposed to an antigen for the first time, it takes time for the immune system to respond and produce antibodies specific to that antigen.
In the meantime, the person is susceptible to becoming ill.
Once the antigen-specific antibodies are produced, they work with the rest of the immune system to destroy the pathogen and stop the disease.
Antibodies to one pathogen generally don’t protect against another pathogen except when two pathogens are very similar to each other, like cousins.
Once the body produces antibodies in its primary response to an antigen, it also creates antibody-producing memory cells, which remain alive even after the pathogen is defeated by the antibodies.
If the body is exposed to the same pathogen more than once, the antibody response is much faster and more effective than the first time around because the memory cells are at the ready to pump out antibodies against that antigen.
This means that if the person is exposed to the dangerous pathogen in the future, their immune system will be able to respond immediately, protecting against disease.
How vaccines help?
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.
Some vaccines require multiple doses, given weeks or months apart. This is sometimes needed to allow for the production of long-lived antibodies and development of memory cells. In this way, the body is trained to fight the specific disease-causing organism, building up memory of the pathogen so as to rapidly fight it if and when exposed in the future.
Herd immunity
When someone is vaccinated, they are very likely to be protected against the targeted disease. But not everyone can be vaccinated. People with underlying health conditions that weaken their immune systems (such as cancer or HIV) or who have severe allergies to some vaccine components may not be able to get vaccinated with certain vaccines.
These people can still be protected if they live in and amongst others who are vaccinated. When a lot of people in a community are vaccinated the pathogen has a hard time circulating because most of the people it encounters are immune.
So the more that others are vaccinated, the less likely people who are unable to be protected by vaccines are at risk of even being exposed to the harmful pathogens. This is called herd immunity.
This is especially important for those people who not only can’t be vaccinated but may be more susceptible to the diseases we vaccinate against.
No single vaccine provides 100% protection, and herd immunity does not provide full protection to those who cannot safely be vaccinated. But with herd immunity, these people will have substantial protection, thanks to those around them being vaccinated.
Vaccinating not only protects yourself, but also protects those in the community who are unable to be vaccinated. If you are able to, get vaccinated.
Throughout history, humans have successfully developed vaccines for a number of life-threatening diseases, including meningitis, tetanus, measles and wild poliovirus.
I remember when I was wee boy at school in the 1950’s when children had been infected by polio and some ended up wearing steel callipers on their legs. The US war president FDR caught polio as an adult had to wear steel callipers and ended wheel chair bound.,
What is Polio?
- Polio, or poliomyelitis, is a disabling and life-threatening disease caused by the poliovirus.
- The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis (can’t move parts of the body).
Symptoms
Most people who get infected with poliovirus (about 72 out of 100) will not have any visible symptoms.
About 1 out of 4 people (or 25 out of 100) with poliovirus infection will have flu-like symptoms that may include:
- Sore throat
- Fever
- Tiredness
- Nausea
- Headache
- Stomach pain
These symptoms usually last 2 to 5 days, then go away on their own.
A smaller proportion of people (much less than one out of 100, or 1-5 out of 1000) with poliovirus infection will develop other, more serious symptoms that affect the brain and spinal cord:
- Paresthesia (feeling of pins and needles in the legs)
- Meningitis (infection of the covering of the spinal cord and/or brain) occurs in about 1 out of 25 people with poliovirus infection
- Paralysis (can’t move parts of the body) or weakness in the arms, legs, or both, occurs in about 1 out of 200 people with poliovirus infection
Paralysis is the most severe symptom associated with polio, because it can lead to permanent disability and death. Between 2 and 10 out of 100 people who have paralysis from poliovirus infection die, because the virus affects the muscles that help them breathe.
Even children who seem to fully recover can develop new muscle pain, weakness, or paralysis as adults, 15 to 40 years later.
Picture of leg callipers
Polio was virtually eliminated by the polio vaccinations and I remember at school getting my shot.” I whined my way into the doctor’s office, fully expecting a sharp, pointy needle. To my joyous discovery, the vaccine I received came in the form of a sugar cube. I happily gobbled it down, and in the process received life-long protection from polio.
For me taking a vaccination for Covid 19 is a sensible precaution against this airborne virus. I have two AstraZenca vaccines and a one Modena booster vaccination.
I can’t understand the logic of refusing to have a vaccination to protect from awful virus as Covid 19 and it’s various mutations?