How The Immune System Fights the Coronavirus
- The immune system’s production of antibodies is a primary response to viral and bacterial invasion. However, this is not the only way the body fights infections.
- Booster doses help to shore up your immunity against SARS-CoV-2.
- Many countries have encouraged their citizens to take booster shots in the face of the Omicron variant. This variant can overcome some of the protection offered by the vaccines.
While more countries are rolling out booster doses of COVID-19 vaccines, discussions over the efficacy of these doses are ongoing and center on breakthrough infections, decreasing antibody levels, and variants with a high level of transmissions, such as Omicron and Delta.
These three factors are interrelated.
But here’s the thing – as antibody levels decline a couple of months after complete vaccination, the level of protection will decrease, especially from the Omicron and Delta variants. Both variants are highly contagious and could increase breakthrough infections.
Also, preliminary data shows that the Omicron variant can overcome some of the protection offered by the vaccines.
As the name implies, booster doses enhance your immunity against SARS-COV-2, the virus responsible for COVID-19.
But there’s more to this booster shot debate than this.
When considering how well COVID vaccines work overtime, one should understand that there’s more than one type of effectiveness. Yes, some vaccines might prevent or reduce the risk of mortality or severe illness but may have less protection, thus leading to minor symptoms.
It is also important to note that antibodies are just one out of many tools used by the immune system to fight infections. Therefore, when you rely only on antibody levels, you miss the protection offered by other immune system components.
Either way, it is crucial to understand the mechanism of action of antibodies and what waning levels might mean for protection against COVID-19.
Overview of antibodies
Antibodies are proteins produced by the immune system. They are Y-shaped and are produced in response to an infection. Antibodies identify specific molecular structures and bind to them. These molecular structures are called antigens. Antigens may be found on the surface of a bacterium or a virus.
Most antibodies that fight or prevent coronavirus infection usually bind to the virus’s spike protein surface. The coronavirus uses its spike protein to infect cells.
Antibodies are produced by B cells of the immune system. B cells are found in the spleen, the blood, lymph nodes, and other tissues. Each B cell produces a specific antibody.
According to research, the human immune system can produce over a trillion unique antibodies.
When the human body encounters a pathogen or a virus for the first time, a B cell binds to that pathogen and becomes activated.
After it is activated, the B cell multiplies and recreates different cells. One of these cells is the plasma in which antibodies are produced.
Antibodies remain in the body after infection. However, they don’t stay there for long. Their numbers wane over the months or years, depending on the pathogen.
What to know about the adaptive and innate immune systems?
Antibodies and B cells are components of the adaptive immune system. The adaptive immune system is a part of the immune system that targets specific pathogens.
The other part of the immune system is known as the innate immune system. The innate immune system defends the body generally against infection.
The innate and adaptive immune systems can work together to fight or weaken a bacterium or a virus before you get critically ill. If there is a new virus or bacterium in your body, the innate component of your immune system will quickly sense that something is wrong and respond to the invading pathogen.
This is important because it can take days to weeks for your adaptive immune system to fight off a specific pathogen.
But once your immune system is exposed to that pathogen, it will be fortified and more ready for it when next it invades. This means that the immune system may be able to fend off the invading virus or bacterium before you experience any symptoms.
When exposed to a particular pathogen for the first time, your adaptive immune system will develop something called memory cells. These memory cells are formed both on the T-cell and the B-cell sides.
Helper T cells, a type of T cell, will stimulate your B cells to create antibodies. A different kind of T cell known as killer T cell will attack cells infected by a pathogen.
How do vaccines work?
Vaccines trigger the same immune response without the risk of disease as natural infection.
Vaccination tricks your body into creating antibodies. When you are exposed to the real deal, you’re already fortified from that assault.
Vaccines accomplish this by presenting your immune system with an antigen.
Some antigens contain an inactivated or weakened form of the pathogen. Other vaccines contain just a part of the pathogen.
COVID-19 mRNA is designed to teach cells how to produce antibodies that target the spike protein of the coronavirus.
How many antibodies does your body need?
Your immune system produces different kinds of antibodies in response to a pathogen. Some of these antibodies bind very strongly to an antigen. Others bind weakly.
Antibodies can be divided into neutralizing and non-neutralizing antibodies. Neutralizing antibodies are capable of neutralizing a pathogen.
For instance, when responding to SARS-CoV-2, some neutralizing antibodies bind to the spike protein on the coronavirus and prevent it from infecting your body cells.
Although non-neutralizing antibodies cannot do this, they can still help fight pathogens. They can recognize viral pathogens that are presented or exposed on the surface of infected cells.
Studies suggest that most labs measure the neutralizing antibodies since it gives an idea of how well-protected you are.
However, with COVID-19, we do not clearly understand our body’s right antibody level to protect us from severe disease or infection. In addition, identifying this immune response is somewhat complicated because your immune system has several ways of protecting your body besides antibodies. This includes T-cell-mediated or cellular immune response.