The coronavirus family includes a wide variety of viruses, which can cause respiratory infection. The novel covid-19 virus (SARS-CoV-2) was discovered in January 2020 and has since infected more than 72 million people, with over 1.6 million deaths as a result of covid-19 disease (14 December 2020).

Enormous resources are now being put into developing and testing various vaccines against the covid-19 virus.

As no one has previously managed to produce an effective vaccine against coronavirus, it is not known what type of vaccine would be most effective, or even whether it is possible to produce a vaccine, which prevents people from becoming ill. The fact that companies and research scientists are focussing on different types of vaccine is therefore beneficial.  

New technology

Although the research groups are using different technologies, the purpose of the vaccine remains the same: to enable the immune system to fight infection.

Many of the covid-19 vaccine candidates are based on the spike protein (S protein) on the surface of the coronavirus SARS-CoV-2. This S protein is important for the virus to attach itself to cells, penetrate them and use the cells to produce new viruses. Upon vaccination, the body produces antibodies to the S protein. Neutralising antibodies prevent the virus from entering cells.

Since we are developing vaccines against a new virus and, in some cases, using completely new vaccine technologies, it is essential that the vaccines are tested thoroughly. The clinical studies must show whether the vaccines really do protect against disease and whether protection lasts for a reasonable period of time. We must also monitor whether any unacceptable side effects occur. However, it is not known if the new technologies will be any better than the old ones. This can only be determined through large clinical trials.

Some of the vaccines use known technology

Inactivated virus vaccines

The vaccine consists of the covid-19 virus, which is killed (inactivated).

The inactivated virus does not cause disease, but the body is stimulated to produce antibodies that can fight the covid-19 virus if the person subsequently becomes infected with it.

This technology is used in the polio vaccine and some influenza vaccines.

Vaccine candidates in phase-3 which use this technology:

  • Sinovac (China and others)
  • Sinopharm (Beijing)
  • Sinopharm (Wuhan)

Vaccines which contain parts of the virus (subunit vaccines)

The vaccine contains parts of the covid-19 virus. The vaccine parts do not cause disease, but the body is stimulated to produce antibodies that can fight the covid-19 virus if the person subsequently becomes infected with it.

This technology is used in the vaccine against hepatitis B and some influenza vaccines.

Vaccine candidates in phase-3 which use this technology:

  • Novavax (US)

Viral vector - non-replicating

These vaccines do not contain the covid-19 virus, but another type of virus in which a part of the genetic material from the covid-19 virus has been inserted.  The virus (i.e. the vector) cannot multiply in the body.

When the virus (vector) enters the body's cells, the cells will use the piece of genetic material from the covid-19 virus to produce the characteristic "spike" protein.

The spike protein does not cause disease, but the body will produce antibodies to it and prepare immune cells (T-lymphocytes) that together with antibodies can fight the covid-19 virus if the person subsequently becomes infected with it.

This technology is used in some Ebola vaccines.

Vaccine candidates in phase-3 which use this technology:

  • Astra Zeneca and Oxford (UK)
  • Sputnik (Russia)
  • CanSino (China)
  • Johnson & Johnson (Janssen) (US)

Other vaccines utilise technology not previously used in vaccines

RNA vaccines

These vaccines contain a piece of the genetic material (RNA) from the covid-19 virus (the piece that encodes the "spike" protein). The RNA is "wrapped in" small fat particles which help the genetic material enter the cells in the body. The body's cells use the piece of genetic material from the covid-19 virus to produce the characteristic "spike" protein.

The spike protein does not cause disease, but the body will produce antibodies to it and prepare immune cells (T-lymphocytes) that together with antibodies can fight the covid-19 virus if the person subsequently becomes infected with it.

This type of vaccine has never been used before.

Conditional marketing authorisation for vaccine candidates which use this technology:

 

Oppdatert: 06.01.2021

Publisert: 17.12.2020

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