Viral Vectored Vaccines

Genetic material from the infectious agent for which a vaccine is required is incorporated into an unrelated virus which then acts as carrier or vector of the genetic material.

Once in the body, some viral vectors can be modified to multiply in a harmless way. This increases the amount of ‘vaccine’ available and stimulates the immune system in their own right, enhancing the overall response to the vaccine.

Watch this video to learn more about viral vectored vaccines:

A PDF summary of the video can be found in the downloads section below.

The image below summarises how the University of Oxford viral vectored vaccine for COVID-19 (ChAdOx1 nCoV-19) is made.

Click here to expand image

Viral vectored vaccines are also a relatively new type of vaccine. The only licensed vaccine of this type is the Ebola vaccine, rVSV-ZEBOV, which uses a vesicular stomatitis virus which is a virus that causes infections in cattle.

Advantages	Limitations
Can be manufactured more quickly and for less cost than egg-based vaccines	It is not clear whether a single vector can be used for multiple vaccines
Produce broad immune responses that include T-cell as well as B-cell responses

We will now find out more about the final type of vaccine – recombinant protein/subunit vaccines and the use of virus-like particles.