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Vaccine Development – The First Steps

This article explains how vaccines work and the changes in vaccine design. It includes a video explaining "reverse vaccinology".

Vaccines work by ‘showing’ the immune system a weak or inactive pathogen, or part of the pathogen against which an immune response is needed to provide protection against future infection. This is known as an antigen.

An infographic explaining how vaccines work. It has three circles, one for each stage. The first circle is a depiction of vaccines introducing a weak or inactive form of the disease into the body, the second is the body reacting by stimulating the immune system and creating antibodies, whilst the third is the antibodies remembering the disease and defending against if a person becomes re-exposed.

Image from Allegro Pediatrics

One of the first challenges in vaccine development can be trying to identify the best antigen to use. This can require knowledge of the biological and genetic structures of the pathogen and how the host immune response provides protection.

The way that vaccine antigens are identified has changed greatly over the last 40 years and now includes ‘reverse vaccinology’. This is where vaccine developers start with the genetic sequence of a pathogen and use this to choose and/or deliver an antigen. In the video below, Professor Rino Rappuoli explains some of the important changes in vaccine design and how he led development of the field of ‘reverse vaccinology.’

This is an additional video, hosted on YouTube.

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

In the next few steps we will examine vaccine design, looking specifically at creating a vaccine against SARS-CoV-2.

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Vaccine Development: Finding a Vaccine for COVID-19 and Future Pandemics

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