Vaccines prepare a person’s immune system (the body’s natural defenses) to recognize a particular disease and defend against it.
Scientists are working on several types of vaccines against COVID-19, using different technologies.
The EU portfolio currently includes vaccines based on four different technologies:
mRNA (uses part of the genetic code of the coronavirus)
vaccines based on a viral vector (a genetically modified virus is a carrier of part of the DNA of the coronavirus)
protein-based vaccines (contain fragments of a protein that is unique to the coronavirus)
vaccines with inactivated virus (made from live virus by chemical inactivation)
vaccine mRNA
The mRNA molecule is naturally used by our body as a guide for the creation of all the proteins we need. Scientists have built on decades of research into mRNA to use as a basis for vaccine development.
While researching the coronavirus, scientists discovered a protein, the so-called spike protein that allows it to enter human cells and infect them. They artificially created instructions for the creation of this protein, the so-called messenger RNA, or mRNA. These instructions are a key component of the vaccine.
This is a new approach to vaccines, as they contain no part of the virus, just instructions for your cells to make a protein similar to the coronavirus protein, triggering an immune response and equipping you with the resources to defeat the real virus.
Pfizer/BioNTech and Moderna vaccines against COVID-19, which use mRNA technology, have been approved in the EU.
Vaccines based on viral vector
Viral vector-based vaccines use a harmless virus to deliver instructions from the coronavirus into our bodies to make a protein unique to the COVID-19 virus and thereby trigger an immune response.
The EU-licensed COVID-19 vaccines from AstraZeneca and Janssen are viral vector-based vaccines. The Sputnik V vaccine, which is currently under continuous review by the EMA, is also a vaccine based on a viral vector.
An important advantage of viral vector-based vaccines is that they are very durable and can be stored at room temperature in a refrigerator for up to six months. Another advantage of the Janssen vaccine is that one dose is sufficient to achieve immunity against the virus.
Protein-based vaccines
This type of vaccine contains fragments of a protein that is unique to this virus.
This is enough for the immune system to recognize that this unique protein should not be present in the body and respond by launching a natural defense response against the infection of COVID-19.
The first protein-based vaccine to be approved for use in the EU is the vaccine produced by Novavax. The Sanofi/GSK vaccine, which is authorized for use in the EU, is also a protein-based vaccine.
Vaccines with inactivated virus
This type of vaccine contains parts of the actual COVID-19 virus that has been inactivated in the laboratory to destroy its ability to cause disease.
When the immune system comes into contact with the inactivated virus, it responds by creating a natural defense against the infection of COVID-19.
Valneva’s vaccine, which is authorized for use in the EU, is an inactivated virus vaccine.