The European Medicines Agency and AIFA have authorised two anti-COVID-19 protein subunit vaccines. This is the Nuvaxovid vaccine (recombinant, adjuvanted) from the pharmaceutical company Novavax.

Protein subunit vaccines are composed of "protein fragments" of the virus. In the production of this type of anti-COVID-19 vaccine, a portion of DNA containing the information necessary to produce the spike protein is inserted inside a baculovirus.

Subsequently the baculovirus will infect some cells in vitro which will release the genetic material useful for the production of the spike protein. The latter will then be extracted, purified and compacted to obtain viral nanoparticles that contain spike protein.

These particles, added with an adjuvant molecule used to further stimulate the immune system, are thus ready to be injected into the human body to obtain the production of antibodies against the SARS-CoV-2 spike protein.