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ΑρχικήEnglish EditionHow well do you know your coronavirus vaccine?

How well do you know your coronavirus vaccine?

By Evanthia Vasiliki Tagari,

The truth is that the coronavirus vaccine was and is redemption in terms of dealing with the pandemic and in general our reintegration into normal life rhythms. Nevertheless, these vaccines are still questionable in terms of their functional capacity, mainly due to the short period of their clinical trials, thus making them less reliable. The existence of the side effects in individuals -which in some cases can even lead to death- reinforces the fear, and leaves no room for the necessary wall of immunity, according to the scientific community. But because knowledge is power and only through this way can one recognize the truth about the logic of these vaccines, let us see what they contain and how they work in our bodies.

But what is the virus referred to as SARS-CoV-2 that causes coronavirus and how is it introduced into our body?

Coronavirus disease (COVID-19) is an infectious respiratory disease caused by a newly discovered coronavirus. This virus is also referred to as SARS-CoV-2. The cause of infection from the latter is a specific protein that allows the virus to infect human cells. This protein, whose cells normally carry on their surface, is called angiotensin 2 converting enzyme (ACE2) and provides the entry point for the coronavirus to enter the cells. ACE2 is present in all people, but the amount of this protein can vary from person to person and to different tissues and cells throughout the body. This enzyme is mainly found in organs of the body such as the lungs, small intestine, and nasal cavity. More specifically, the COVID-19 virus using a protein-like spike binds to ACE2 on the surface of the cell and thus enters it. But because ACE2 generally produces proteins that regulate normal cell function, not only does it act as an entry point for the virus, but its dysregulation affects the inflammation and cell death of lung cells. Therefore, it is concluded that people with higher levels of ACE2 in the body, such as patients with hypertension, diabetes, and coronary heart disease, are more likely to be infected with the virus.

Image source: https://athenslab.gr/blog/diagnostikes-exetaseis-diagnostictests/viologia-ton-koronoion

How does the body’s normal defense work to fight disease?

To understand the function of COVID-19 vaccines, it is important to first understand the broader rationale behind the normal treatment of diseases in our bodies. After the infection of the body, i.e. the invasion, attack, and multiplication of germs, such as the COVID-19 virus, the disease is caused. Our immune system then uses many tools to fight infections. Blood is one of them. Red blood cells carry oxygen to tissues and organs, while white blood cells, or immune cells, fight infection. The latter is of great importance for the body’s analogical response as they contain different cell types with clearly defined functionality. White blood cells include macrophages that digest foreign cells leaving “antigens” in the body, or parts of the invading microbes, which are then recognized by the body as dangerous, thus triggering antibodies to attack them. Another type is B-lymphocytes which act defensively, producing antibodies that attack the virus fragments left behind by macrophages. Finally, T cells are another type of defense white blood cell that attacks cells in the body that are already infected. After infection, the body retains some T-lymphocytes, called “memory cells”, which are activated quickly if the body encounters the same virus again. When known antigens are detected, B-lymphocytes produce antibodies to attack them. So, somehow, the individual’s immune system remembers how to protect the body from this disease.

COVID-19 vaccine = Prefabricated body defense

COVID-19 vaccines help our body develop immunity to this virus without having to get sick. The logic of all vaccines is common and is involved in creating memory T cells as well as B cells that will remember how to deal with a possible future virus infection. This process, of course, may take a few weeks after vaccination to be completed and effective defense against it can be obtained. This is why people are more likely to get COVID-19 even if they have been vaccinated. Also, as part of the body’s defense against COVID-19, it is possible for symptoms such as fever to appear after vaccination. The latter is normal and is an indicator of the body’s immune system.

Image credit: gettyimages

Types of vaccines against COVID-19

Today, there are three main types of COVID-19 vaccines approved and recommended or undergoing large-scale clinical trials (Phase 3). Note that none of these vaccines can cause COVID-19, as it does not contain the necessary genetic information that is responsible for its appearance in the body.

mRNA vaccines. mRNA vaccines use a genetic code called RNA to trigger the production of this coronavirus-specific protein. Once the mRNA enters the cells of the body, the cells use the instructions contained in the RNA to create the spike protein. The immune cells then recognize the spike protein as foreign and begin to build an immune response against it. The RNA from the vaccine does not change or interact with our DNA in any way. BioNTech-Pfizer and Moderna vaccines follow this logic.

Protein subunit vaccines. Protein subunit vaccines contain harmless parts (proteins) of the virus that cause COVID-19 instead of the whole germ. Once vaccinated, our body recognizes that the protein should not be there and builds T-lymphocytes and antibodies that will remember how to fight the virus that causes COVID-19, if we become infected in the future. One such vaccine is Novavax COVID-19.

Vaccines of vectors. These vaccines contain a modified version of a virus other than that caused by COVID-19. Inside the shell of the modified virus, there is material from the virus that causes COVID-19. This is called a “viral vector”. Once the viral vector is inside our cells, the genetic material instructs the cells to make a protein that is unique to the virus that causes COVID-19. Using these instructions, our cells make copies of the protein. This triggers our body to make T-lymphocytes and B-lymphocytes that will remember how to fight this virus if we become infected in the future. Such vaccines are contained in Oxford-AstraZeneca, Sputnik V, and Johnson & Johnson formulations.

In summary, the coronavirus entered our lives abruptly in December 2019 and changed it decisively in all areas of everyday life. Nevertheless, a single glance at the past is enough to realize how nature coped with similar situations and how humanity was reborn from its ashes. Vaccines are the epitome of this vital renaissance, and trust in the scientific community alone can do no harm.

  • Center for Disease Control and Prevention, How Vaccines Work, Available here
  • Australian Government – Department of Health, How do Covis-19 Vaccines Work, Available here
  • World Health Organization, Coronavirus, Available here



Evanthia Vasiliki Tagari
Undergraduate of the Department of Chemistry at the University of Ioannina who laughs out loud and speaks even louder. Advocate of gender and racial equality, women's rights and environmental protection through her participation in parliamentary simulations. She expresses herself with amateur dance, endless conversations with friends and photography. She loves the independence, honesty and exchanging cultures during her trips. Despite the excellent use of Greek and English in oral and written language, what stands out is the power of body language in the empathy of daily contact. Her attitude towards life is included in the phrase "Get where you cannot!" of Nikos Kazantzakis.