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How vaccination works? What will happen in my body?



The vaccine against Covid-19 is a drug protecting individual from the disease caused by the new coronavirus SARS-CoV-2 by inducing immune system reaction against the virus. In layman’s terms, vaccine learns the body where are the weaknesses of the virus and how to produce adequate immune system reaction so that your immune system could kill the virus before its reproduction in the body.

The availability of a safe and effective vaccine against Covid-19 is necessary to secure protection against the disease, especially for medical workers, risk groups (e.g., pensioners or chronically ill persons).

How the vaccine works and how long lasts the protection?

The vaccines learn our immune system how to recognize the causative agent of the viral disease and how to defend the body against him. Covid-19 vaccine developers concentrate their attention on inducing the reaction against the protein (or its part) on the surface of the coronavirus (so-called spike protein or S protein) – this protein is the unique identification of the virus. After the vaccination, the immune system will be able to produce the desired reaction. If a vaccinated person is infected, the immune system will recognize the virus and will be able to protect vaccinated individual against the disease caused by SARS-CoV-2.

As we are facing quite a new virus, we do not have sufficient research knowledge about the length of immunity induced by the vaccine and whether regular revaccination is needed. The data from immunogenicity and vaccine effectiveness studies will help us in the long term to (re)define future vaccination strategies.

Protection against mutations

Viruses can mutate (change their genetic material); different viruses mutate differently while mutations need not have an impact on the quality of vaccine protection. Some vaccines against viral diseases retain their ability to protect for many years. Example of vaccines providing long-lasting protection is measles or mumps vaccine. On the other hand, there are diseases (such as influenza) with greater ability to change the virus strains. Thus, there is a need to modify e.g., influenza vaccine to ensure the quality of protection.

The scientific community and regulatory bodies closely monitor whether the SARS-CoV-2 virus mutates and if the vaccine will provide the protection also against new mutations.

Vaccine side effects

After the vaccination, there may be headache, fatigue, or aching limbs. It is normal to have certain reactions after vaccination, mentioned side effects are not symptoms of the disease. The goal of vaccination is to learn our immune system how to fight the disease. This process however might have above-mentioned inconveniences.

In rare cases, severe negative side effects might occur. However, the probability of serious side effects is much lower than the probability of the infection.