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How does the COVID-19 vaccine work?

The vaccines used in Finland against COVID-19 are so-called mRNA vaccines, adenoviral vector vaccines and protein-based vaccines. All types of vaccines provide equally efficient protection against the coronavirus disease. These vaccines do not contain the virus causing the coronavirus disease.

The abbreviation RNA refers to ribonucleic acid which is located in cells. The messenger RNA code instructs the cell to produce the proteins that are indispensable for the body. In addition to the messenger RNA, the vaccine contains water, salts, sugar and lipids.

The mRNA vaccines contain messenger RNA (mRNA) whereby the muscle cells in the point of injection are triggered to produce the active ingredient of the vaccine.  In case of COVID-19 vaccines, this is the surface protein of the COVID-19 virus. When the surface protein is dosed into the body, the body starts to produce antibodies against it, i.e., it starts to build protection against the potential COVID-19 virus. 

Adenoviral vector vaccines also induce the vaccinated person’s own muscle cells to produce the COVID-19 virus surface protein. The operative mechanism is different – the adenoviral vector vaccines contain a gene copied from the COVID-19 virus, and the code contained in it starts to produce the COVID-19 virus surface protein, the so-called spike protein, in the cells. 

In vaccines, this gene is included as a part of the genotype of a harmless viral vector, the adenovirus. Correspondingly to mRNA vaccines, the adenoviral vector vaccines also contain water, salts, sugar and lipids, and do not contain a reproductive COVID-19 virus.

The active substance in protein-based vaccines is a COVID-19 spike protein produced in laboratory. The body begins to protect itself against the foreign spike protein by producing antibodies and activating helper T cells. This produces protection against the possible COVID-19 virus. In addition to the spike protein the vaccine contains an adjuvant, Matrix-M. The vaccine also contains water, salts and polysorbate 80 as excipients, as well as small amounts of other substances that maintain the consistency of the vaccine. The vaccines do not contain the live virus that causes COVID-19.

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Page published 28.04.2021 | Page edited 31.10.2023