Universal flu vaccine breakthrough

Are we a step closer to a universal flu vaccine that blocks any flu infection and lasts several years? That's the hope. Scientists in America have homed in on certain parts of the outer coat of the influenza virus that are the same in many different forms of flu. And because those regions can't change, because doing so would affect the ability of the virus to infect and grow, the vaccine can provide longer term protection. This week they published the results of their first clinical trial of the approach in humans. Karin Bok is the Deputy Director at the NIH Vaccine Research Center...

Karin - Influenza virus is very, very smart. And I would say even much smarter than coronaviruses. They have many, many tools at their disposal to evolve, to change, to avoid being targeted by our immune system.

Chris - The virus is essentially sidestepping immunity by looking different.

Karin - Yes.

Chris - So even though we've been vaccinated, or even caught flu previously, that doesn't endow us with defence against a virus that now looks different.

Karin - Exactly. It's almost as if you were getting in touch with a new virus, a new influenza, every year. So what we have to do is study very carefully the virus at the microscopic level and try to find pieces of that virus that do not change. There are some pieces of the virus that are either more hidden from our immune system or the virus is not able to change that part because it would mean catastrophic consequences for their growth.

Chris - If those components of the virus that don't change, these so-called conserved areas, are in all these flu viruses, and they're already there, why don't we make our own immune response when we catch flu against those so that we are immune to all future flus?

Karin - Another great question, and the answer to that is because the virus is very smart and the most exposed parts of the virus, the parts that our immune system sees first, are the ones that we are most likely to react to and are the ones that the virus changes every year.

克里斯,我想这里有两个问题:one is you've got to find a way to make the immune system respond to these bits of the virus that it wouldn't normally respond to because the virus hides them, so you've got to disclose them in some way. And then you've got to prove that once you've got that immune response to those bits, that it is a protective immune response.

Karin - Exactly. Yeah.

Chris - And how have you achieved each of those aims? Let's start with how you have made the immune system see what was formally invisible on the virus, parts that it kept hidden so we wouldn't react to it?

Karin - So this is a very cool process and it is the same process we used to make the SARS CoV 2 vaccine. We call them designer vaccines, because it's the first time we've gone to the smallest part of a virus. We say, "we don't like the way the virus has built this part of their outside. We're going to try to rebuild it ourselves in the lab, and we're going to try to use that as a vaccine." So we're not only saying we're going to target parts of the virus, we're also redesigning the virus because, if we redesign it, the immune system will respond better. And by redesigning we mean stabilising. We really cut parts of the virus that we don't want to be there, and we redesign it to be a stable vaccine. So the immune system sees it and has an immune response.

Chris - What's in the tin? What's going on? Do you take the gene that corresponds, or the piece of genetic information that corresponds to the thing you want and make cells make that which you then purify with your modifications intact? And that's what you are giving the patient in order to see if the immune system will respond?

Karin - So in order to build a new building, you need to know how to build buildings. First we have to study the virus itself to see how it's built. And then, as you said, we take that gene for that part of the virus and we modify the gene before putting it into the cells. And we grow it and then we purify it and we use it as part of our vaccine.

Chris - And then how do you address part two, which was proving that when you expose a person or an animal or whatever to that modified protein that you've made, it is protective and it it is protective in the long term, which is your goal against lots of different types of flu.

Karin - This study that we just published is the first attempt to vaccinate humans. And, as you know, the first time you vaccinate a human it's just to establish the safety of the vaccine. So we haven't been able to test that in humans, but in animals and in the lab, in cells, we know that it blocks the virus. So there is proof that this part of the virus in a vaccine is able to generate the kind of immune response that we want in a vaccine.

Chris - And does that include not just longevity of the response, which was one of your goals, but also if I come along with a completely different kind of flu and expose a vaccinated individual to that, they would be protected?

Karin - Yeah. And what we've been able to understand is that you have, or the animal that's immunised with this vaccine has an immune response to other types of flu that are not present in the vaccine. And that is a breakthrough which is why we're excited.