Can this trojan horse make it?

The Oxford University-developed vaccine, which has been licensed to British pharma major Astrazeneca, can best be described as deploying a Trojan horse strategy to stimulate the human system into building an immune response that can beat the Sars-cov-2. We explain how:

THE ‘VECTOR’

The vaccine uses what is known as a “viral vector”. The researchers took what’s called an adenovirus that causes cold in chimpanzees (and is thus harmless to humans) and bio-engineered it to include components of the Sars-cov-2.

TRAINING THE BODY

This component is genetic material of the Sars-cov-2’s surface protein, also known as the spike ‘S’ protein. It is this that the virus uses to infect humans, and is also what antibodies bind to. Being exposed to this component – which is now innocuous because it comes with a virus that does not infect humans – will train the body to recognise it and act on it faster.

WHAT THE VACCINE DOES

The Phase 1 trial report indicated that the vaccine was able to trigger an immune response at both levels: antibodies as well as killer T cells were found in the blood of inoculated volunteers.

‘DOUBLE PROTECTION’

This is significant because a T cell response indicates the immunity will last for a significant amount of time, since T cells and B cells (which produce antibodies) are part of the body’s second line of defence: the one that learns to fight an unknown pathogen and retains that information.

THE ADVANTAGE

Traditional vaccines are made with a weakened or inactivated form of the pathogen. These might not be easy to produce quickly and at scale. The Oxford team uses technology it learned and perfected while developing a vaccine for Mers, also a coronavirus.

It is the bio-engineering strategy that allows this vaccine to be produced quickly and at scale, since even an inactivated form of a virus that is deadly for humans requires exceptional amount of safety precautions – which might not be needed here.