How does the COVID-19 vaccine work?

The vaccines used currently in Finland against COVID-19 are so-called mRNA vaccines and adenoviral vector vaccines. Both types of vaccines provide equally efficient protection against the coronavirus disease, in other words, they increase the protective antibody contents to an equal extent in the human body. mRNA and adenoviral vector vaccines do not contain the virus causing the coronavirus disease or its elements.

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.

Further reading


Page published 28.4.2021
Page edited 28.4.2021