How does a vaccine work?

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Vaccines contain antigens, that is, substances that stimulate the immune system to produce effective protection against the viruses and bacteria that cause particular diseases.

Vaccines are produced in two ways. In the first case, they are produced from live attenuated (i.e. attenuated – blog) microorganisms. Microorganisms prepared in this way should not cause disease in the person vaccinated with them. The second way to produce vaccines is to produce them from dead microorganisms, which, as in the first case, should not harm the vaccinated person.4,5

Some vaccines contain only selected and purified specific microbial particles. The introduction of micro-organisms or fragments of micro-organisms weakened in the body by vaccination does not present a risk for the child. When the vaccine is given, the body reacts as if it had been infected with a pathogenic microorganism, but no symptoms of disease develop. It is a kind of “immune training”.

Antigen. Vaccination allows contact with antigens and the immune system recognizes the components of the vaccine as an infection – it begins to produce antibodies and immune cells.

Antibody. This event remains in the body's immune memory.

immune memory. It will therefore be able to recognize real microorganisms (bacteria or viruses) that will attack the body in the future and quickly defend itself against them.5,6 In this way, the vaccinated person acquires immunity against microorganisms. specific organisms in a controlled way, avoiding the risk of complications and the danger they represent.

Authentic microorganisms. Vaccination against a given disease usually consists of several doses to be given to the child at specific intervals – when the required age is reached and at specific intervals. Vaccines are given by injection – subcutaneously, intradermally or intramuscularly – or orally as a suspension5.

In addition to the vaccinations provided for in the vaccination schedule, it is important to keep in mind the vaccinations recommended for people of different ages, both the child and his relatives: brothers and sisters, parents, grandparents.

Comment fonctionne un vaccin ?

A few months ago, scientists around the world scrambled to develop an effective vaccine against COVID-19 as soon as possible. These international efforts to fight the pandemic culminated in the launch of the SARS-CoV-2 vaccination on December 27, 2020 in Poland. How does the coronavirus vaccine work and is it safe? We have prepared an article to answer your questions.

How does the coronavirus vaccine work?

Comment fonctionne le vaccin contre le coronavirus ?

The vaccine makes it possible to acquire immunity against an infectious disease without having to undergo it. The goal of vaccination against the coronavirus is to provide the body with B cells, which are white blood cells that produce protective antibodies that attack virus fragments, and T cells, which are white blood cells that attack cells infected with the virus.

It is important to note that the coronavirus vaccine must be given in two doses. The vaccines developed by the researchers are divided into mRNA vaccines, subunit vaccines and vector vaccines – they are distinguished by their mode of action.

Vector vaccines

Vector vaccines do not contain coronavirus antigens. However, they are equipped with a weakened version of the adenovirus (which causes the common cold), which delivers the appropriate genetic code to human cells and stimulates them to produce SARS-CoV-2 proteins. It looks like a natural infection, which triggers both a T-cell immune response and B-cell antibody production. The advantage of vector vaccination is that it triggers a strong immune response, and this technology is used in science for years.

Subunit vaccines

Contains purified viral proteins that enter antigenic cells and produce an immune response. Purified proteins are incapable of causing disease. This type of vaccine against COVID-19 is therefore suitable for people with weakened immune systems. However, their immune response may be much weaker than that of next-generation vaccines and therefore less effective.

Side effects of the coronavirus vaccine

The COVID-19 vaccine was developed almost at a run, so there are understandably concerns about its performance. It should be noted, however, that the side effects experienced by those vaccinated appear to be harmless. On the other hand, the consequences of contracting COVID-19 can unfortunately be very serious. The makers of the vaccine, Pfizer-BioNTech and Moderna, observed short-term side effects in subjects, such as pain at the injection site, fever, chills, headache, muscle or joint pain. . The aforementioned symptoms are transient and also occur after other vaccines, such as those against hemiplegia or influenza.

The Center for Health Protection and Prevention (CDC) has documented several cases of anaphylaxis in vaccinated people. The organization therefore recommends that people who have already had an anaphylactic reaction after vaccination not to receive the coronavirus vaccine or to consult their doctor.

Vaccins sous-unités

Pfizer and Moderna also report that several people in the study group (four people at Pfizer and three at Moderna) experienced Bell's palsy, or temporary facial paralysis. However, the Food and Drug Administration (FDA) assures that there is not enough information at present to determine a link between vaccination and this phenomenon, but the FDA nevertheless constantly monitors the situation.


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