Hope for new malaria vaccine: Naturally immune children helping scientists

Scientists believe they have found an effective new vaccine against malaria, the world’s most deadly vector borne disease.

Using blood samples from naturally immune children in Tanzania, researchers discovered an antibody that may be key to stopping malaria’s spread in the body. Last year alone, the disease’s parasites—carried by mosquitoes—killed over 600,000 people worldwide, so the discovery represents a potentially significant blow against malaria’s spread.

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Researchers have yet to try the new malaria vaccine on humans, but trials on mice have shown high promise. Scientists will move to trials on monkeys next; assuming that is successful, they then hope to conduct small studies on people.

Halting the Parasite

Scientists designed the vaccine to mimic certain children’s immune response to malaria parasites.

The Tanzanian children, who were identified during a standard blood test as naturally protected from malaria, made up only 6 percent of the group tested.

Scientists from the Brown University School of Medicine used the group’s blood samples to isolate a particular protein critical to malaria’s spread in the body and determine how the naturally immune children’s bodies dealt with that protein, called PfSEA- 1.

According to The Guardian, the disease’s parasites need PfSEA-1

“in order to escape from inside red blood cells they infect as they cause malaria…the immune children were producing an antibody that locked PfSEA-1 into their red blood cells, stopping [the parasite’s] spread.”

In designing the new malaria vaccine, then, scientists are taking a new tack on stopping malaria parasites. Leading researcher Jonathan Kurtis said that it’s a matter of reframing the question to consider how they might keep parasites from leaving the red blood cells, using a version of the children’s antibodies, rather than stopping the parasites from ever entering those cells.

Extended Survival Rates

With that knowledge, the scientists in Tanzania were able to significantly extend the malaria survival rate for mice, offering hope for malaria victims around the world.

After mice were injected with SEA-1, one of the proteins produced by naturally immune human children, researchers found that those test animals were able to survive previously lethal doses of the malaria virus: mice with SEA-1 lived double the amount of time as those that were unvaccinated.

Tests also showed that the vaccinated mice had a four-fold decrease in the number of parasites in their blood, as compared to unvaccinated mice.

Hopes for Use

If this malaria vaccine does prove effective for humans, it could potentially help over half of the world’s population.

The World Health Organization reports that as of 2013, 97 countries and territories—made up of 3.4 billion people—had “ongoing malaria transmission.” Though 90 percent of deaths attributed to malaria are in sub-Saharan Africa, other areas of the world affected by illness from the parasite include Latin America and Asia, as well as certain parts of the Middle East and Europe.

The Centers for Disease Control and Prevention notes that in Latin America, malaria transmission is low but disproportionately affects young children and pregnant women. The danger of malaria is higher in lowland and rainforest areas that make key breeding grounds for mosquitoes.

While scientists are optimistic about the study’s initial results, they caution that there’s plenty more research that needs to be done.

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