News / Health

    New Malaria Vaccine Passes Safety Test

    Researchers focus on improving effectiveness

    Adult mosquitoes feeding on human blood containing malaria parasite.
    Adult mosquitoes feeding on human blood containing malaria parasite.

    Multimedia

    Audio
    Art Chimes

    The fight against malaria may have taken a promising step forward with the latest tests of a new kind of vaccine, which aims to keep people healthy and prevent the infection from spreading.

    Most malaria vaccines under development work by including genetically engineered versions of just a handful of the thousands of proteins of the Plasmodium parasite. Those modified proteins are designed to trigger an immune response to Plasmodium, after it’s passed into the host’s bloodstream by the bite of an infected mosquito.

    In contrast, says researcher Robert A. Seder of the U.S. National Institute of Allergy and Infectious Diseases, this new vaccine includes a deactivated version of the entire parasite.

    "So instead of picking out one or two or three genes," he says, "you have the potential for what we call breadth - generating an immune response that would be broad rather than narrower. And so that would be a good thing."

    Sanaria staff produces the PfSPZ vaccine in the company's clinical manufacturing facility.
    Sanaria staff produces the PfSPZ vaccine in the company's clinical manufacturing facility.

    Plasmodium goes through many stages in its life cycle. To make this vaccine, scientists use the parasite at the stage - called the sporozoite - when it's ready to infect new hosts. They remove the sporozoite from the mosquito's salivary glands and then subject it to radiation.

    That weakens it, so it can't cause malaria symptoms, and can't be transmitted via mosquito to another person, either.

    This concept has been known since the 1960s, but Seder says there were practical obstacles that prevented the development of a malaria vaccine.

    "The major breakthrough here was that my collaborator, Stephen Hoffman at [vaccine company] Sanaria, developed a method where he could isolate the sporozoites and purify them so that they could administer it as a vaccine to humans. And no one thought that that was possible," he explained.

    Adult mosquitoes ready for vaccine production.
    Adult mosquitoes ready for vaccine production.

    And no one knew if the weakened sporozoites would jump-start the immune system to protect against malaria.

    To find out, researchers used human volunteers. The vaccine was injected into their skin with a needle, to simulate the bite of a mosquito. From a safety standpoint, the results were good - there were only relatively minor side effects. But a vaccine must be safe and effective, and this one just wasn't very effective. Only two out of 44 volunteers who got the vaccine were protected when bitten by malaria-infected mosquitoes.

    To find out why, the researchers then switched to laboratory animals, and Seder says they concluded that the problem was the way the vaccine was administered.

    "Had [Hoffman] given [the vaccinations] in the vein, intravenously, directly in the blood, rather than through the skin, he would have gotten much higher immune responses."

    That would be unusual for a vaccine, which is typically given by mouth or as a skin or muscle injection. It also might complicate mass vaccination programs, if the vaccine goes into general use.

    Cost is also an issue, but researcher Seder says it's too soon to know how the vaccine will be priced - assuming it is effective.

    The next stage of human testing - using intravenous administration - is due to start in October.

    You May Like

    Top US General: Turkish Media Report ‘Absurd'

    General Dunford rejects ‘irresponsible' claims of coup involvement by former four-star Army General Campbell, who led NATO forces in Afghanistan before retiring earlier this year

    Video Saving Ethiopian Children Thought to Be Cursed

    'Omo Child' looks at efforts of one African man to stop killings of ‘mingi’ children

    Protests Over Western Troops Threaten Libyan 'Unity' Government

    Fears mount that Islamist foes of ‘unity' government plan to declare a revolutionaries' council in Tripoli

    This forum has been closed.
    Comments
         
    There are no comments in this forum. Be first and add one

    Featured Videos

    Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
    London’s Financial Crown at Risk as Rivals Eye Brexit Opportunitiesi
    X
    VOA News
    July 25, 2016 5:09 PM
    By most measures, London rivals New York as the only true global financial center. But Britain’s vote to leave the European Union – so-called ‘Brexit’ – means the city could lose its right to sell services tariff-free across the bloc, risking its position as Europe’s financial headquarters. Already some banks have said they may shift operations to the mainland. Henry Ridgwell reports from London.
    Video

    Video London’s Financial Crown at Risk as Rivals Eye Brexit Opportunities

    By most measures, London rivals New York as the only true global financial center. But Britain’s vote to leave the European Union – so-called ‘Brexit’ – means the city could lose its right to sell services tariff-free across the bloc, risking its position as Europe’s financial headquarters. Already some banks have said they may shift operations to the mainland. Henry Ridgwell reports from London.
    Video

    Video Recycling Lifeline for Lebanon’s Last Glassblowers

    In a small Lebanese coastal town, one family is preserving a craft that stretches back millennia. The art of glass blowing was developed by Phoenicians in the region, and the Khalifehs say they are the only ones keeping the skill alive in Lebanon. But despite teaming up with an eco-entrepreneur and receiving an unexpected boost from the country’s recent trash crisis the future remains uncertain. John Owens reports from Sarafand.
    Video

    Video Migrants Continue to Risk Lives Crossing US Border from Mexico

    In his speech Thursday before the Republican National Convention, the party’s presidential candidate, Donald Trump, reiterated his proposal to build a wall along the U.S.-Mexico border if elected. Polls show a large percentage of Americans support better control of the nation's southwestern border, but as VOA’s Greg Flakus reports from the border town of Nogales in the Mexican state of Sonora, the situation faced by people trying to cross the border is already daunting.
    Video

    Video In State of Emergency, Turkey’s Erdogan Focuses on Spiritual Movement

    The state of emergency that Turkish President Recep Tayyip Erdogan has declared is giving him even more power to expand a purge that has seen an estimated 60,000 people either arrested or suspended from their jobs. VOA Europe correspondent Luis Ramirez reports from Istanbul.
    Video

    Video Calm the Waters: US Doubles Down Diplomatic Efforts in ASEAN Meetings

    The United States is redoubling diplomatic efforts and looking to upcoming regional meetings to calm the waters after an international tribunal invalidated the legal basis of Beijing's extensive claims in the South China Sea. VOA State Department correspondent Nike Ching has the story.
    Video

    Video Four Brother Goats Arrive in Brooklyn on a Mission

    While it's unusual to see farm animals in cities, it's become familiar for residents of Brooklyn, New York, to see a little herd of goats. Unlike gas-powered mowing equipment, goats remove invasive weeds quietly and without adding more pollution to the air. As Faiza Elmasry tells us, this is a pilot program and if it proves to be successful, the goat gardener program will be extended to other areas of New York. Faith Lapidus narrates.
    Video

    Video Scientists in Poland Race to Save Honeybees

    Honeybees are in danger worldwide. Causes of what's known as colony collapse disorder range from pesticides and loss of habitat to infections. But scientists in Poland say they are on track to finding a cure for one of the diseases. VOA’s George Putic reports.
    Video

    Video Wall Already Runs Along Parts of US-Mexico Border

    The Republican Party’s presidential nominee, Donald Trump, gained the support of many voters by saying he would build a wall to keep undocumented immigrants and drugs from coming across the border from Mexico. Critics have called his idea impractical and offensive to Mexico, while supporters say such a bold approach is needed to control the border. VOA’s Greg Flakus has more from the border town of Nogales, Arizona.
    Video

    Video New HIV Tests Emphasize Rapid Results

    As the global fight against AIDS intensifies, activists have placed increasing importance on getting people to know their HIV status. Some companies are developing new HIV testing methods designed to be quick, easy and accurate. Thuso Khumalo looks at the latest methods, presented at the International AIDS conference in Durban, South Africa.
    Video

    Video African Youth with HIV Urge More Support

    HIV, the virus that causes AIDS, is the top killer of teens in sub-Saharan Africa. But many youths say their experience with the virus is unique and needs to be addressed differently than the adult epidemic. VOA South African Correspondent Anita Powell reports.
    Video

    Video Pop-Up Art Comes to Your Living Room, Backyard and Elsewhere

    Around the world, independent artists and musicians wrestle with a common problem: where to exhibit or perform? Traditional spaces such as museums and galleries are reserved for bigger names, and renting a space is not feasible for many. Enter ArtsUp, which connects artists with venue owners. Whether it’s a living room, restaurant, office or even a boat, pop-up events are bringing music and art to unexpected places. Tina Trinh has more.
    Video

    Video Scotland’s Booming Whisky Industry Fears Brexit Hangover

    After Britain’s vote to leave the European Union, Scotland’s government wants to break away from the United Kingdom – fearing the nation’s exports are at risk. Among the biggest of these is whisky. Henry Ridgwell reports on a time of turmoil for those involved in the ancient art of distilling Scotland’s most famous product.

    Special Report

    Adrift The Invisible African Diaspora