By Anoushka Ghosh
Living through a pandemic means that we spent the entirety of our year either self-isolating or practicing social distancing. These are the precautions we can carry out till the vaccine is produced. The very act of manufacturing a vaccine requires time and precision because the lives of millions lie in the hands of doctors, physicians, and researchers everywhere. Hence, it requires immense knowledge and scrutiny to create a vaccine. One needs to carry out different experiments and a variety of tests on subjects to create a vaccine. So that the vaccine would not be a liability to public health. If a vaccine requires so much examination and scrutiny, how does it work then?
A vaccine is the safest way for people to protect themselves against infectious diseases like COVID-19 or Polio. Once you are vaccinated, you can fight off the disease rapidly when you come into contact with this disease. This is because they have an increased level of protection or immunity against the disease. But, how does a vaccine work?
To understand the mechanisms of a vaccine, we should first learn about our immunity system. When we talk about infectious diseases, we would be talking about infections caused by a pathogen. A pathogen is a disease-causing organism such as bacteria, fungi, or a virus. Thus, our body would recognize a pathogen as an intruder and respond to it immediately.
When thinking about the type of immune response, there are two types: active immunity and passive immunity. Active immunity is the phenomenon when the host produces antibodies when exposed to the pathogens such as a virus or bacteria, while passive immunity is when the host receives antibodies from another source. For instance, active immunity is when we are vaccinated, whilst passive immunity is when the fetus absorbs antibodies from the mother's blood.
When we get infected by a virus, our body is activated by an organism or cell it doesn't recognize as its own; we would call this the pathogen. In more technical terms, these are known as antigens which include the proteins on the surfaces of bacteria, fungi, and viruses. Our body has B cells and T cells. The B cells are the lymphocytes that identify the antigens and engulf them. After being activated by the helper cell, the B cell separates into two different cells: plasma cells and memory cells. The plasma cell produces antibodies.
Antibodies and antigens are two elements that interact with each other. There is an antibody for every particular pathogen because its shape matches it and allows it to attach to the pathogen. We know that antibodies have lymphocytes and phagocytes: lymphocytes are white blood cells that are involved in producing antibodies, whilst phagocytes are white blood cells that kill pathogens by engulfing them and digesting them (phagocytosis).
But, what happens after the antibodies act against the pathogen? Well, lymphocytes release memory cells that remain in the blood. If the pathogen invades the body again, then memory cells would respond by dispatching the antibodies. This type of response is known as active immunity.
So, why is this relevant? Well, with the growing number of COVID-19 cases, people are in a frenzy to get a vaccine. Let's dive into the technicalities of the COVID-19 vaccine. There are three types of vaccines: mRNA, protein subunit, and vector vaccines. These different types of the vaccine provide various types of protection, but they all end at the same point with a supply of "memory" T cells which would fight the virus in the future. Keep in mind that none of them can verify protection against the virus one day after you take the vaccine. It needs a duration of at least 1 to 2 weeks which makes you susceptible to COVID-19.
Let's discuss the vaccines. Firstly, the mRNA vaccines contain material from the virus that causes COVID-19. Once the mRNA is inside the immune cells, they are then used to make a protein piece. After the protein piece is made, the cell breaks down the instructions and gets rid of them. Next, the cell displays the protein piece on its surface. Our body recognizes that the protein piece does not belong to the body, and it triggers an immune response where antibodies are made.
Next, we have the protein subunit vaccine, which includes harmless pieces of the virus that causes COVID-19. Our body will recognize that the virus does not belong there, so it causes an increase in the production of T-lymphocytes and antibodies.
Lastly, the vector vaccine uses a modified version of a different virus (also known as the vector) to deliver instructions to our cells. First, the vector which is not the COVID-19 virus is inserted into the body and enters a cell. It then uses the cell machinery to produce a harmless piece of the COVID-19 virus. It is known as the spike protein that is only found on the surface of the COVID-19 virus. Soon, our body realizes that the virus doesn’t belong in the body and triggers an immune response from our body.
In the end, all the vaccines depend upon the memory cells to fight the virus immediately upon attack. We must understand the side effects of each vaccine: for instance, the protein subunit and vector vaccines don't seem to work as efficiently as the mRNA vaccine. This is because the other two vaccines expose people directly to the actual COVID-19 cell, whilst the mRNA vaccine is taking the genetic code of the COVID-19 germ and encoding the viral protein in our body. This way there is no insertion of the actual COVID-19 cell into our body.
Hence, you must educate yourself about the different types of vaccines before taking them. Make sure to properly hydrate yourself and consume food, so that you are not weak. Remember your health comes first in any circumstances, so take care of it.
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