How Close Are We to a Malaria Vaccine? - The Comprehensive Minds

 How Close Are We to a Malaria Vaccine?

Malaria

Before COVID, many other diseases plagued our world ... and they haven't just disappeared. In fact, the current pandemic has made many other epidemics even more difficult to treat and control. But there is good news on the horizon because recent advancements give us more immunity than ever before against one of the world's oldest and deadliest infectious diseases. That disease is malaria

Malaria affects more than 200 MILLION people and kills approximately half a million people each year. In fact, it is one of the leading causes of death for children under 5 years of age in the world. And it has been around for literally thousands of years. But we still don't know ... Why? 

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 parasites into the human’s bloodstream...so...ta-da, infection. 

Plasmodium

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. 

Malaria Vaccine

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. 

mRNA vaccine

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. 


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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. 

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