fact, the current pandemic has actually made  many other epidemics even harder to treat  

and control. But there's good news on the  horizon, because recent breakthroughs are  

bringing us more immunity than we've ever  had before to one of the world's oldest  

and deadliest infectious diseases. That disease is malaria.   

Malaria affects over 200 MILLION people and kills about half a million people every year.  

It's actually one of the world's leading  causes of death for children under 5. 

And it's been around for literal millenia.  But we still don't have a handle on it...

Why is that?

Well, malaria is caused by a parasite—a  group of them, actually, called Plasmodium. 

These parasites are transmitted  by some species of mosquitoes.  

When an infected mosquito bites a human. The  mosquito regurgitates some of the parasite  

into the human's bloodstream...ta-da, infection. From there, the parasites move to your liver,  

where they multiply and mature into the form  that can move on to infect your red blood cells.  

This is the point at which you develop  symptoms—fever, chills, headache, vomiting,  

muscle pain. In severe cases, this can lead to  trouble breathing, organ failure, and even death. 

And the measures we currently have to combat this  disease aren't really that great. Antimalarial  

drugs can be really rough on your body.  We actually give them not only to treat  

the disease, but also to prevent it...And  one analysis found that these drugs may only be  

up to 72% effective at preventing malaria. PLUS, the darn parasites keep developing  

resistance to many of these drugs.  We also have tools that target the mosquitos  

themselves instead of the parasite

like insect nets and bug spray.

And these play a huge role in malaria prevention, but the availability of  

all of these tools is easily disrupted by things  like civil unrest or...the COVID-19 pandemic. 

So, a more long-acting, more effective solution would be  HUGE.  

A solution like a vaccine. The thing is, 

there is no approved vaccine for any parasitic  disease of any kind. See, when we make a vaccine,  

we're trying to get your body to protect itself by  introducing it to the parts of the pathogen that  

would make you sick, what's called an antigen.  For COVID, that's the viral spike protein. 

But parasites are generally much more  complex pathogens than bacteria or viruses,  

so those antigens are more complicated.  But there are some options on the horizon.  

The most advanced candidate so far is called  Mosquirix. It has actually been approved by the  

European Medicines Agency and passed through phase  III trials,

but it's not yet approved by the World Health Organization.

It contains one of the parasite's main surface  proteins as the antigen, 

and that's produced in a lab by inserting

the DNA that codes for the antigen into a microbe,  like a yeast. The microbe produces that antigen,  

we put it into the vaccine, and that  antigen activates your immune system  

against the parasite.

But this vaccine doesn't provide full  protection—it's around 30-40% effective  

in some trials

against malaria infection over the course of  about 4 years, and that decreases over time. 

Another vaccine that works in a really similar way, called R21, has come onto the scene  

more recently and improved on the amount of  protection, with some studies showing up to 77%  

effectiveness, but it's still  early in its trial stages. 

The NIH recently tested another kind  of vaccine, a live-attenuated type.  

That means it contains the whole, live parasite,  but it's been weakened by something—in this case,  

by radiation—to make it so it can't actually  infect you.  

This candidate can provide 

100% protection, but only against the exact same  strain of parasite that's included in the vaccine. 

Because there are many species of Plasmodium, and  within species there are different strains, this  

vaccine provides incomplete protection against  strains that are different from the parasite  

that's in the shot. And the newest member to join  this cast of characters is one we're all used to  

hearing about these days...because it's an mRNA vaccine.

Using the same technology that's behind the  

Pfizer-BioNTech and Moderna COVID vaccines, this  malaria vaccine candidate contains mRNA that  

codes for the antigen—one of the parasite's surface proteins. 

Instead of having the actual protein itself in the  

vaccine, like the Mosquirix and R21 candidates  do,  

or having the whole live parasite in it, like that NIH vaccine,

this vaccine contains just the mRNA, 

and your cells are what's making the protein. BioNTech recently tested this vaccine  

in mice, where it yielded 88% protection.  The company has its sights set on having the  

world's first mRNA vaccine for malaria  available for use in humans by 2022. 

Now, all of these candidates still face many  hurdles, from having enough facilities to make  

each kind of vaccine, to the logistics of  getting them to the people who need them.  

And while none of them are licensed and  on the market yet, we could be just a few  

years away from the world's first ever approved  parasite vaccines—maybe letting us swat malaria  

away for good, and changing the world forever.  

If you want more positive infectious disease news, 

check out this video over here, and for more  buzz on all things vaccine, make sure you  

subscribe to Seeker. If you have another  public health topic you want us to cover,  

leave us a comment down below and as always,  thanks for watching. I'll see you next time.