INTERVIEW: Dr Jacco Boon on a possible new nasal vaccine for COVID-19

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A COVID-19 vaccine (AAP) Source: SIPA USA / Roberto Silvino/IPAIPA/Sipa USA

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Researchers using a nasal vaccine approved in India and licensed for U-S development found that vaccinated hamsters didn’t spread the virus, unlike those receiving traditional injected vaccines. Published on July 31 in Science Advances, these findings indicate that mucosal vaccines could be crucial for controlling respiratory infections like COVID-19 and influenza. Essam Al-Ghalib spoke with the study's author, Jacco Boon, a professor of medicine, of molecular microbiology and of pathology and immunology.


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TRANSCRIPT

AL-GHALIB: Dr Jacco Boon, thanks for joining us today, all the way from St. Louis, Missouri, in the United States. You've got some exciting news about something that has the potential to wipe-out Covid altogether. Tell us about it, please.



BOON: As the pandemic started, hopefully, many of us got vaccinated and this has been a huge lifesaver for a lot of people. It really reduced severe disease in many people and allowing us to just kind of overcome the infection. What we started working on early on in the pandemic is a model or a an animal model of transmission, where we were trying to model how the virus transmits within communities or households and for this, we actually use a very susceptible animal, the Syrian hamster.

And the question that we had was is a mucosal or an intron. Easily delivered vaccine. Is it superior over an injectable vaccine in terms of preventing infection from a from a donor or a or a source or an infected person? And what about if you're vaccinated that then you reduce the ability to transmit to others? And so that was essentially the study that we conducted.

AL-GHALIB: What did your study find?

BOON: We showed that compared to an injectable vaccine, that the mucosal vaccine was much more efficient at reducing viral loads or virus titers in the upper and lower airways, and that the mucosal vaccine prevented onward transmission in this model. That we had developed in in the laboratory.

AL-GHALIB: That sounds very promising. Who developed this vaccine?

BOON: So this is a vaccine that was developed at Washington University in St. Louis, in United States and has been licensed to a company in India, and they are delivering it through drops, I believe. I think it's also been licensed or it's been, it's going to be tested in phase one and phase two clinical trials in the United States. And they're trying to come up with ways of delivery, whether it's drops or whether it's a nasal spray. So these are some of the questions that remain to be answered.

AL-GHALIB: So this vaccine is now available to the public in India?

BOON: It is. Yes.

AL-GHALIB: Ok. Is that how it's being tested? Has it been tested on humans before?

BOON: Um, I cannot speak to the regulations in India. It's, they performed a very different type of study. They performed essentially a immunogenicity study. So there's a difference between an immunogenicity study and an efficacy study. immunogenicity is where you're measuring the immune response following a vaccine. And if that meets a certain criteria, that in some cases is sufficient to proceed, whether they have something to do with the pandemic at the time and in the dire situation. I can't speak to that. I do not believe they've done an efficacy study. So it's not clear how well this vaccine works in in people at this at this point in time, but it's been extensively tested and several animal models.

AL-GHALIB: You say mice and hamsters.

BOON: And non-human primates.

AL-GHALIB: How did that go? What did you see in the mice, hamsters and non-human primates?

BOON: So in mice and hamsters, again, the mucosa we delivered vaccine a superior over an injectable. Both the version of bacteria that we're using as well as other injectable vaccines. It is better at reducing viral titers in the upper airways which is really kind of the Achilles heel of our immune system almost. Our our nose is just very sensitive to virus infection and our immune system is not well designed or optimised to block virus and this is not just SARS Coronavirus, but there's influenza virus there is Respiratory Syndrome virus, rhinoviruses, animal viruses there are many different viruses that seem to really like our our nose and upper respiratory tract for infection. It has to do with our immune system. A struggling to control replication at that site.

AL-GHALIB: So this would take any kind of virus that trying to enter your body and would stop it at your nose or mouth?

BOON: That is what we are hoping for.

AL-GHALIB: Would you take this on a daily basis or would you do this once a year?

BOON: These are great questions. Certainly not on a daily basis. Now. We're hoping that similar to let's say the flu vaccine or even the COVID 919 vaccine, that you could take this once a year, maybe a little bit sooner. If there's if there's a new variant emerging that we have to respond to. But yeah, no, this is this should be taken in a similar way as the injectable vaccines just hoping to provide better protection than what we can currently provide.

AL-GHALIB: What does it smell like, what does it taste like?

BOON: We don't know. I can't tell. As far as I know nobody in the US has ever had it and that information is not available from our sources in India. Ya, it's a good question.

AL-GHALIB: There have been cases of people who were injected with the Covid-19 vaccines suffering Myocarditis / Pericarditis, do we know if that risk will it be eliminated with the nasal or oral applications?

BOON: We don't know yet.

AL-GHALIB: When do you think we'll have a lot more answers? And when do you think this will actually be tested to Western standards, and released in the US, Australia?

BOON: I hope that that will happen in the next two or three years. I think this paper really speaks to the significance of a mucosal and intranasal vaccine. Lots of doctors and scientists have previously known that that was a desirable route of delivery. A story like this really kind of hammers at home with showing very clearly and very elegantly, that the mucosal vaccine has such a superior impact on transmission and community spread compared to an injectable vaccine. So it may not be this vaccine or this deliver this vector, but hopefully it highlights the need for more investment and more research on a mucosal vaccine. that targets the upper airways and maybe improve immunity over what we face now is naturally provided following an infection.

AL-GHALIB: So, what is the news? You know, it's still it hasn't been developed. It still hasn't been tested. We're not really sure when it's coming out. So what is the news? I mean, respectfully, I'm just what are we celebrating here?

BOON: (Laughs). It's a good question. Ah, like I said earlier, I, we were the first to show that in in a lab setting using an animal model that you can do this type of onwards for secondary transmission, and then showing such a significant impact o f the mucosal vaccine over an injectable was never shown before. Neither for flu nor for SARS and so we're the first to do that.

AL-GHALIB: SARS is becoming a concern all over the world now. Even here in Australia. Chickens. We've had the culling of hundreds of thousandsof chickens. Can this vaccine be used in animals to perhaps prevent SARS?

BOON: Yes, in theory it occurred although in chickens influenza, this particular influenza you're talking about is not necessarily a respiratory, only a respiratory infection. It's actually a systemic infection. So injectable vaccines could be as effective. There are, though, challenges with vaccinating chickens regulatory challenges, but I'd like to say a little bit more about the entire situation of the avian influenza which is really challenging. It is affecting birds throughout the world. It has massive impacts on wildlife. And the current outbreak in cows in the United States is somewhat worrying. So yeah, we're definitely looking into that. We are thinking about developing the same internasal or mucosal vaccine for H5 influenza, and seeing if it's effective as well, both in mice as well as in hamsters so that other companies can take that data and interpret it the way they want.

AL-GHALIB: So you've tested this vaccine on mice, hamsters and primates, have they suffered any negative side-effects?

BOON: Not that we're aware of this is very difficult to study, cause side effects in anything but a human it's hard to measure and hard to quantify. So but as far as severe outcomes, morbidity, such as loss of appetite, and those kinds of things have not been observed. So it seems to be effective. With all these vaccines, it becomes more challenging once you start vaccinating larger and larger populations because only then you'll find out about the rare events and the potential side effects that smaller studies and then the studies would never have detected.

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