Let's learn about the COVID-19 vaccine
You may have recently received the COVID-19 vaccine, but do you know how it works? In this post, I'll be discussing the workings of the immune system, and the types of COVID vaccines.
Hello everyone, Abhinav here! I hope you’re all having a great weekend because today I’ll be talking about the COVID-19 vaccines. Hopefully, you’ll have more knowledge on this subject and will be able to decide on which vaccine you want to get. Without further ado, let’s give you today’s dose of knowledge!
Let’s start with the immune system
Our immune system is what protects us from getting sick all the time. Germs and unwanted bacteria constantly enter our bodies; and the immune system, which is composed of “warrior” cells and chemicals eradicates these unwanted cells.
We can say you got an infection if anything from viruses, bacteria, and microbes enter your body and multiply. Now, how does the immune system fight against this attack?
Let’s treat our body as a castle and our immune system as the army. The army mostly consists of white blood cells (WBC).
There are many types of WBCs, but we’ll only be talking about three main types (I’ll explain what these are in a bit):
Macrophages
B-lymphocytes
T-lymphocytes
When the foreign entities enter our bodies and start to multiply, the immune system sends in the infantry - macrophages.
Friend or Foe?
Before we get into the specifics, let’s talk about how WBCs differentiate between healthy and unwanted cells. The bone marrow is where all the types of WBCs are produced. These WBCs are trained to consider antigens part of the body as friends. Other antigens such as those on infectious cells are considered foe and are hostile. This activates the immune response. By the way, antigens on friendly cells tell the WBCs that they are not dangerous. The ones on harmful cells can cause diseases, and that’s a red flag.
Macrophages
Macrophage translates to “big eaters“ in Greek. You can predict what role macrophages play based on this translation. Macrophages engulf the unwanted cell and digest it so that it is harmless. This process of engulfing cells is called phagocytosis. This makes it easier for other WBCs to deal with the infection since the macrophages took care of the dangerous part. Macrophages don’t digest all of the cells, they leave behind the antigens of the cell so that other WBCs can produce specific antibodies to counteract those antigens. Basically, antibodies stop antigens from entering and damaging the “good cells”.
B-Lymphocytes (B cell)
Since we’re talking about antibodies, do you know what produces these antibodies? B-lymphocytes produce the antibody that is specific to the antigen present on the “bad cell”. These antibodies go to where the antigen is attacking and creates a wall so that these antigens can’t pass.
T-Lymphocytes (T cells)
These WBCs are born from stem cells, found in the bone marrow. The developing T cells travel to the thymus to mature, hence the name “T cells”. The cells then mature into different types of T cells in the thymus. If you did click the hyperlink you should know that stem cells are special human cells that can differentiate into many cell types which explains the T cells maturing into different types. We’ll be talking about a certain type of T cell called the killer T cell (that’s a dope name).
Killer T cells kill certain types of cells which are cancer cells, virus-infected cells, and foreign cells. These WBCs have T cell receptors (TCR). TCR comprises a family of antibodies. So the Killer T cell will produce a TCR-like antibody that binds to the antigen of any of the cells that are listed and kills them.
After infection eradication
After the infection has passed, some of the WBCs become memory cells. These memory cells remember how to attack this certain infection so that the next time it appears, the body will know how to get rid of it immediately. That is your immune system getting stronger.
Vaccines
There are many types of vaccines. We got toxoid vaccines, mRNA vaccines, Viral Vector vaccines, etc. You can learn all about them here. We’re gonna be talking about three types of vaccines that are provided in the US by companies: Johnson & Johnson, Moderna, and Pfizer-BioNTech.
Johnson & Johnson
Johnson & Johnson’s vaccine is a viral vector vaccine. “Well this sounds complicated”, is what you might think, but let’s take it step by step.
First of all, what is a viral vector?
Viruses have evolved so much so that they developed mechanisms to transport their own genetic material to infected cells. You can modify a virus to transport certain genes to a target cell. This modified virus is called a viral vector. Viral vectors are used in gene therapy to add new genes to the cells.
How can a viral vector act as a vaccine?
First, the vector (a harmless virus) goes into a cell and makes it produce a harmless piece of the virus that does cause COVID-19. That piece is called a spike protein.
The spike protein is then noticed by the immune system as a foreign entity. The immune system commences an attack and produces antibodies to fight off what it thinks is an infection.
Now the body knows how to protect itself against COVID-19 because it knows how to defeat the virus that causes it. It remembers how to defeat it by producing memory cells (remember we talked about this earlier).
Pfizer & Moderna
Both Pfizer and Moderna have the same type of vaccine - mRNA vaccine. There are only some differences between the two that I will discuss in the end.
What is mRNA?
Yes, we don’t only have DNA; we also have mRNA and tRNA (the body’s so complicated). We’ll only be talking about mRNA because it relates directly to the vaccine. mRNA (messenger RNA) is the molecule that puts the instructions from the DNA into action.
How can mRNA aid in vaccination?
Both mRNA and viral vectors make the cell produce the spike protein. Once the mRNA is inside the cell, it uses these instructions to create that spike protein. The mRNA automatically breaks down after the protein is made.
Since the protein piece is foreign, the immune system is activated and attacks the harmless spike protein as if it was an actual virus. The immune system now knows how to protect itself from the COVID-19 virus because it defeated the spike protein.
Differences between Pfizer & Moderna
Pfizer
age: 16+
time: at least 21 days before the second dose
storage temperature: -94 F (-75 C)
Moderna
age: 18+
time: at least 28 days before the second dose
storage temperature: -4 F (-20 C)
Additional information
You can find the different side effects of the Moderna vaccine here.
You can find the different side effects of the Pfizer vaccine here.
You can find the different side effects of the Johnson & Johnson vaccine here.
You can learn more about the different vaccines here.
Conclusion
Well, that’s it for today’s post about the different types of COVID-19 vaccines. I hope you learned a lot more about the different types of vaccines and that this information will help you decide which vaccine to take. Thank you so much for reading!
That’s your dose of knowledge for today. Let’s meet again next time for another one. Maybe one that’ll take you out of this world. Be positive but test negative!
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well done! I really liked your writing style and the article definitely helped me in deciding what vaccine I should take! (●'◡'●)