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The challenge we face now is that so far no one has been able to produce an effective vaccine against a human coronavirus – and the virus that causes COVID-19 appears to be a real battleship of a virus with many immune-evasion weapons on board.

We know from previous efforts to develop a SARS vaccine, that coronaviruses seem to be able to sometimes “distract” the immune system.

It means our bodies produce antibodies that attack the wrong parts of the virus, rather than the critical structures that the virus uses to break into cells and spread.

WATCH: Vaccine development presents the immune system with only very specific parts of a virus. Video: University of Melbourne

We suspect this may be why some cases of COVID-19 can suddenly become so severe. The immune system gets off track and non-protective antibodies help the virus spread through the body.

So we need to be careful that any vaccine isn’t likewise presenting immune system “distractions” of the virus.

We know that during tests of one failed SARS vaccine, antibodies that were initially considered useful towards the virus, instead quickly caused a very severe case of the disease when the vaccinated animals were challenged with infectious SARS virus.

Here in Australia, we think that the answer to avoiding the immune system getting distracted is potentially creating a vaccine that specifically zeroes-in on that most critical part of the virus needed to block infection.

In the past, vaccine development was about exposing the immune system to many parts of a virus. But most approaches now selectively present the immune system with only very specific parts of a virus to focus crucial antibody immunity.

In the case of COVID-19, we are targeting a spike on the surface of the virus that acts like a sort of spring-loaded box-opener that it uses to pierce and deposit the payload of virus genes into cells.

Once inside it can take over the cell’s genetic coding and reproduce itself while hiding from the immune system.

The team at the University of Queensland, who we are working with closely, are using a technique they developed to grow and clamp in place the spring-loaded spike assembly as a separate structure that they can then introduce to the body – looking like it’s fully-armed.

The aim here is to produce what are called ‘neutralising’ antibodies that prevent the ‘popping’ of the virus’ entry-machinery.

These antibodies are produced by the immune system only in response to this authentic spike structure, so we think the antibodies will be tailored enough to reliably attack, or neutralise, the virus right where we want.

At the Doherty Institute, we are taking a similar and complementary approach.

There is a risk that an immune system exposed to just the spike may end up producing antibodies that attack the wrong end of the spike – its base rather than its tip.

So, we are working on tethering a collection of spikes through their base onto a non-infectious ‘virus-like particle’ – made from a small amount of other virus support proteins.

This could give the immune system a better guide to producing antibodies that can attack the tip of the spike, where the box-opener sits, rather than the base.

It’s all about working at the molecular level to set our immune system on the right track from the start so that it only produces these neutralising antibodies, rather than ‘distracted’ antibodies that don’t hit the virus where it hurts.