An mRNA coronavirus vaccine that could arrive in New Zealand as early as next year, subject to final tests and regulations, would be the latest incarnation of the immunology revolution that's sweeping science. Professor Graham Le Gros, a world-leading immunologist and director of the Malaghan Institute of Medical Research, broke
Covid 19 coronavirus: How will first vaccine available in New Zealand work?
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BioNTech and Pfizer's mRNA coronavirus vaccine could be rolled out in New Zealand early next year, subject to final tests and approval. Photo / Supplied
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However, within a few days, the immune system starts evolving and improving the neutralising binding power of the antibodies to the virus' "spike proteins".
After three to five days, an incredibly lethal neutralising antibody is finally made by the immune cells that eliminates the virus.
And not only is our body's immune system capable of neutralising any type of infectious agent, it also builds up a store of memory responses that are long lasting for the major part of our lives.
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So, if ever we get infected again by the same virus, we doesn't have to go through the same misery, and can completely deal with it and remain safe from further infections.
This is the basis of vaccination, whereby components of the virus are made to stimulate powerful long-lasting immune responses against a virus so that will keep you safe from real infections for many years.
It's critical to understand about this adaptive, immune response, and that's what the immune system is designed around.
Because every pathogen or infectious agent, is quite different.
You have viruses, which are really very small, bacteria, which are a little bit bigger, and then parasites.
If you think about what they present to the body, they're quite distinct challenges.
The immune system has evolved quite distinct ways to deal with viruses, which only live inside our own cells, and with bacteria, which can actually be sometimes outside the cells, and sometimes inside them.
How does this new mRNA vaccine take this concept and apply it to something we can inject?
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Basically, it's taking a component from the virus itself - It's almost like getting one minor part of the virus infection.
In the case of Covid-19, it's an RNA virus: you take a bit of that RNA, you put it in, and actually you're infected with a small part of the virus, appearing as if the virus was infecting you.
But the RNA vaccine only contains the best part of the virus for making a neutralising immune response against the virus.
It doesn't contain the other parts of the virus RNA that can kill the cells of our body, make fevers, make us feel sick and allow virus to replicate and spread to others.
If you make your antibody immune response against the components of the virus vulnerable to immune attack, then, when the real virus comes in, it competing neutralises the virus.
Why might this technology not have been possible 10 years ago? What's changed?
There have been a few major developments.
One has been around understanding how to use RNA, which is inherently unstable chemically, it is naturally designed to have a very short half life.
Learning how to stabilise it more, and how to actually protect it by encapsulating it in special lipids and things like that, has been quite a big technolological advance.
That's helped us manufacture it, then store it so it can be delivered in a form that can stimulate the immune system, and actually get inside cells.
Another big leap has been in identifying what's needed to get that RNA inside the cell, because if it's outside it, it can't actually do anything to stimulate an antibody response.
Do you see this vaccine being the new standard? Or will there still be a place for our traditional types of vaccines?
First, I need to point out very strongly that we do not know yet whether these RNA vaccines really will actually stimulate long-term immunity in a person.
And there could still well be a place for those traditional protein-based vaccines.
Protein vaccines are easy to administer, and suitable for developing countries without health infrastructure like fridges for storage. RNA vaccines will always have a problem in terms of their stability around manufacturing, storage and transport.
If the RNA vaccines can be made to overcome those obstacles, they will be the best.
That's because no matter what pandemic occurs - or no matter what infectious agent comes along - they offer a very fast and effective way of quickly designing and manufacturing a vaccine against something we have never seen before.
Also, they may ultimately be easier to manufacture and involve less additional components, or adjuvants, to boost the immune response.
There's already some misinformation out there around mRNA vaccines and genetic engineering. Why is this not the same as genetic modification?
Because the vaccine does not do any genetic modification to the cells of our body.
The RNA vaccine is simply a component of the virus that is only able to transiently produce specific viral proteins in a cell of our body, just as a virus would, but without the side effects.
The RNA vaccines have no ability to integrate with the DNA, or change the DNA of the host.
The RNA vaccine just uses the cellular machinery of our body like the common cold virus uses in an everyday infection.
What else might we be able to target these vaccines against?
This technology was originally based around trying to make a cancer vaccine.
The recent development that has gone into RNA vaccine for Covid 19 could mean that we have now learned enough that we can go back to that big one - how to create vaccines for all of those solid tumours that we have no solution for at the moment.
But I think using it to deal with all sorts of infectious agents would also be good.
Whether it could work against parasites isn't clear, but there's certainly much to suggest it'll be effective against viruses.
If it passes those tests, then the global population will have a robust, modern way of making vaccines that could surpass our current 30-year-old technology for the seasonal influenza, which remains a major burden on the world.
RNA vaccines could eventually end up being a wonderful solution to some of the major global health issues we face.
