Malaria vaccine to save millions of lives
The World Health Organization has approved a new malaria vaccine that can be produced on a massive scale. It’s hoped that the jab - which has been developed by researchers at the University of Oxford - can help turn the tide against a disease that has killed millions of babies and infants worldwide. So, how does the vaccine work? I’ve been speaking to immunologist Lisa Stockdale…
Lisa - This is a vaccine against malaria, a parasitic infection that kills hundreds of thousands of people a year. In terms of how it works, this vaccine shows the human body a part of the parasite, much like the Covid vaccine using spike to introduce the body to what the spike protein looks like, so that they're ready when they get infected. This is much the same but for malaria.
Chris - How do you actually do that? What's in the tin as it were that you put into the body with the vaccine?
Lisa - In the vaccine vial there is what we call a VLP, which is a virus-like particle. This isn't a virus, it's just that it's small and spherical and has a really high density of this malaria protein that we're trying to show the body on its surface. We inject this alongside what we call an adjuvant. This is a reagent that kicks the immune system into action. And so what happens is that this malaria specific protein on the surface of this vaccine is identified as a foreign object and then the body goes into its normal process of trying to get rid of it. And in that process it develops antibodies against that specific protein.
Chris - Is this an essential part of the parasite then? So if you make those antibodies and they're there waiting, when you encounter malaria for real it clogs it up. Is that how it works?
Lisa - Pretty much, yes. It is essential to the parasite's ability to infect human cells. And so when we inject somebody with this vaccine, we push the human body to make antibodies that are specific to that protein.
Chris - And how good is it in clinical trials?
Lisa - Incredibly good. We have been testing it in African countries that have malaria endemic in the population and the latest data that we have is that when it's administered to people living in areas where malaria is seasonal, this is 75% effective. So you would have 75% fewer people getting malaria if everybody got vaccinated.
Chris - Is this adults, children? Both?
Lisa - This is all children. 5 to 36 months olds.
Chris - There are multiple different types of malaria, aren't there? So will this work against all of them?
Lisa - It will not. So this vaccine that we've just had WHO recommendation for specifically targets plasmodium falciparum. Plasmodium is the malaria pathogen and then falciparum is the specific subtype. So there is also a malaria called vivax, which is particularly present in South America. And this vaccine unfortunately doesn't target that type of malaria.
Chris - Could it be adjusted, updated? Will the same strategy work or are we back to square one with these other forms of malaria?
Lisa - We think that it could be tweaked and actually that's something that our group is working on to try and see if we can make an alternative version of this vaccine specifically for vivax form.
Chris - And how long does the protection last for? Is this a one hit wonder? You have it once and then you are protected indefinitely? Or do you envisage We're going to have to do boosters.
Lisa - The way that the vaccine has been tested so far is that there are three doses given one month apart and then a booster dose given 12 months after the third dose. So that's what's been tested at the moment and that's what we've got data for. Earlier trials containing smaller numbers of participants have tested durability of the vaccine and we know that it maintains out to about three years, but we still need to do further work to understand exactly how long in greater numbers of people.
Chris - Yours is the second malaria vaccine that the WHO have recommended. What's the first one and how does yours compare to that one?
Lisa - The first one is called RTSS and it was developed by a company called GSK and that was recommended by WHO about this time two years ago. Our vaccine and RTSS target exactly the same protein on the surface of the malaria parasite so they are really similar, the main difference being that our vaccine is produced in a different organism and we get higher density proteins on the surface of our vaccine. So we think that that causes the immune response to be more specific to those proteins.
Chris - When are you hoping that this is going to be in the field and what sort of an impact do you think it's going to have?
Lisa - So the WHO have said that this is to be rolled out middle of next year, mid 2024. The manufacturer of the vaccine has vaccines stored and ready to go. And I think that the impact will be enormous. There's a huge issue with the current vaccine not having sufficient doses for the demand that's out there from African countries. So at the moment there's 18 million doses available between now and 2025 for RTSS, whereas the manufacturer that we are working with has said that their capacity is a hundred million doses a year, which could be doubled. So I think in terms of supply and demand, the impact of this WHO recommendation is absolutely enormous.