JOHN YANG: Malaria is one of the world's deadliest diseases.

Throughout Africa every year, it kills nearly a half million children younger than five.

But a new vaccine, only the second of its kind, holds the promise of saving thousands of lives and moving closer to eradicating malaria.

Ali Rogan has more.

ALI ROGIN: At the end of May, the Central African Republic became the first country to receive doses of the new R21/Matrix-M malaria vaccine.

It's intended for children between five months and three years old, who were among the most vulnerable to the disease.

UNICEF, the UN's main organization for children, says eight countries in Africa are set to receive these R21 shipments.

And experts say two vaccines are exponentially better than one, helping not just to immunize more people, but to reduce the illnesses spread.

Andrew Jones is the Deputy Director of Immunization Supplies for UNICEF.

Andrew, thank you so much for joining me.

The first vaccine was rolled out, approved more than two and a half years ago.

So what are the differences between this vaccine and the vaccine that was already available?

ANDREW JONES, Deputy Director of Immunization Supplies, UNICEF: They're very similar vaccines.

In fact, the first vaccine, which is called RTSS, manufactured by GlaxoSmithKline, is largely a copy of this vaccine.

So they're expected to have similar impact in kids.

The big difference when RTSS was released, it was being manufactured in Belgium, and it was being manufactured at relatively old plants.

They were quite limited in capacity, which was a challenge, because, as you can imagine, the demand for this vaccine has been massive.

And so this second vaccine has a much greater supply.

The other point to note is that the first vaccine has to be combined.

It comes in a powder and a diluent.

You mix the two together, whereas this R21 vaccine is fully liquid, so it's a little bit easier to use in the field.

ALI ROGIN: Do you have any sense of how many additional people are going to be able to be vaccinated now that there's two versions on the market?

ANDREW JONES: Well, the initial rollout starts a bit slow.

I mean, it's kind of one of these exponential things where the demand has been pending for a while, and then the message to countries was, well, you know, you're going to have to be a little patient.

This is going to take some time.

And so one of the differences with this vaccine compared to normal childhood vaccines is it's given at a different time.

So, childhood vaccines are given sort of in this age where they're two, three months.

This vaccine's delivered to kids over six months, with the last dose being when they're almost two years old.

They have four doses here.

Our main challenge right now is getting countries ready to accept it.

The additional doses no doubt in the next few years we would have been capped.

So 15, 20 million, we're now not capped.

So we're expecting that.

Well, this year and next year it's a gradual increase.

By 2026 and beyond, we'll see a lot more countries using this vaccine.

And, you know, half a million kids right now die from malaria every year, which is an enormous number.

And so being able to impact that, I mean, there are tools out there like bed nets, like spraying, but this is going to be an important new tool.

ALI ROGIN: What needs to occur for the countries that are receiving the vaccine to be ready to receive them?

ANDREW JONES: Yeah.

So there's a few interesting points.

I mean, one of this is, as I mentioned, is the fact that it's a non-traditional dosing, right?

So these four doses, last one being delivered very late.

So the big difference there is kids aren't necessarily coming to the clinics then.

So it's a new, what we sort of say a new touch point, right?

A new place where parents have to bring their kids.

So I think one of the things is just getting the advocacy and communication out there that you bring your kids back for that.

I think secondly is there's a lot of other interventions out there from malaria.

Right.

I mentioned this, many of the other vaccines against rotavirus, for diarrhea, there's no preventive measure, there's treatment and malaria.

The difference is there's other preventive measures like bed net.

So one of the other challenges is making sure, because this vaccine is only about 40, 45 percent effective, it's making sure that parents and community workers know to keep sleeping under bed nets and using spraying.

ALI ROGIN: Why has it in the past been so difficult to create these vaccines for parasitic borne diseases?

And does the rollout of these two malaria vaccines bode well for the development of other vaccines against other parasitic diseases?

ANDREW JONES: Yeah, it's a good question.

So the malaria parasite is a very tricky parasite.

It's always shifting and changing.

Even this vaccine is 40 or so percent effective.

Again, much like, as you know, in COVID is the time after the vaccination goes, your sort of protection drops.

So it's not as if it's like a single point, right?

It's changing, but 40 percent of a big number is still a big number.

Certainly people who want to eradicate malaria want to see a vaccine that's 80, 90 percent effective, where you can really look at disease elimination.

There are other products in development still a few years out that are aiming to do more in terms of eradicating the disease.

I think with everything we do, we learn more.

There is new TB vaccines that are underway.

There's talk about an HIV vaccine trials, and we would expect for something like an HIV vaccine, for example, we'd also see something that wasn't 90 percent effective.

So even this idea of, from a program perspective of working with a vaccine that's partially effective and what does that mean for your strategies is an important learning experience.

ALI ROGIN: Andrew Jones, deputy director for immunization supplies with UNICEF.

Thank you so much.

ANDREW JONES: Thank you.