News / Health

    Vaccines in Development to Protect Against Dengue Fever

    A boy tries to outrun a man fumigating for mosquitoes in an effort to combat dengue fever, on the streets of Lahore, Pakistan, September 20, 2011.
    A boy tries to outrun a man fumigating for mosquitoes in an effort to combat dengue fever, on the streets of Lahore, Pakistan, September 20, 2011.
    Jessica Berman

    The World Health Organization estimates that 2.5 billion people - more two-fifths of the world's population - are at risk of infection with Dengue fever, a mosquito-borne illness that in its worst form can cause death. Until now, efforts to develop a vaccine against the disease have been unsuccessful. Researchers say a couple of experimental vaccines are showing promise.

    Since Dengue fever was first identified a half century ago, the incidence of the disease has grown dramatically. The World Health Organization says Dengue fever today is endemic in more than 100 countries, and more than 50 million people are infected every year.  

    Scott Halstead, senior advisor to the Dengue Vaccine Initiative, an international consortium of medical research groups, said that fluid treatments for the disease have reduced mortality from the most severe form of the illness. But Halstead added that the rainy season in many parts of the tropics and subtropics - when Dengue-carrying mosquitoes are breeding and biting - is still a time of special anxiety because there is no specific medication or cure for Dengue fever:  

    “While the mortality rate, in reality, is relatively low because of the availability of good hospital treatment, this is almost unlike any other major infectious disease,” said Halstead.

    In its worst form, Dengue fever, also known as "breakbone fever," can cause severe internal bleeding, circulatory failure, shock, coma and death.

    There are four related, but distinct, types of the Dengue virus that are transmitted by the bite of the Aedes aegypti mosquito. The difficulty in developing a vaccine, according to Halstead, is that a person may develop immune system antibodies against one type of virus, but would have no immunity against the other types.  

    Halstead said that sets the stage for more serious infection later on.

    “The antibodies that are left over from the first infection interact with the second type of the virus, and what we say is it “enhances” the infection; it makes it more severe the next time you’re infected with a different type of virus,” said Halstead.

    Experts say it’s usually a second infection with a different Dengue virus that leads to the most severe and sometimes fatal form of the disease - Dengue hemorrhagic fever.

    Two promising vaccine candidates now are in the works to protect against all types of Dengue virus. Both vaccines contain the four types of live but weakened viruses, designed to stimulate the body's production of neutralizing antibodies against all Dengue types.

    French drug maker Sanofi-Pasteur has reportedly invested nearly $1 billion to develop a vaccine that is proving highly effective in phase-three human clinical trials in Thailand, the last step before regulatory approval. A second vaccine, being developed by U.S. drug maker Inviragen, also has proved to be safe and effective in phase-one human trials.

    Dan Stinchcomb, Inviragen’s chief executive officer, said that despite the millions of dollars it has spent so far to develop the Dengue vaccine, the company hopes to keep it affordable.

    “Our intention is to try to produce the vaccine at low cost so that we can provide it with help of funding to the poorest in need of the vaccine,” said Stinchcomb.

    Progress on both Dengue vaccine candidates was reported at the recent meeting of the American Society for Tropical Medicine and Hygiene in Philadelphia, Pennsylvania.

    You May Like

    Hope Remains for Rio Olympic Games

    Facing a host of problems, Rio prepares for holding the games but experts say some risks, like Zika, may not be as grave as initially thought

    Diplomats Hope to Revive Cradle of Civilization After Defeat of IS

    Diplomats from around globe gather at US State Department, discuss how to rebuild minority communities shattered by Islamic State group

    ‘Time Is Now’ to Save Africa’s Animals From Poachers, Activist Says

    During Zimbabwe visit, African Wildlife Foundation President Kaddu Sebunya says poaching hurts Africa as slave trade once did

    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.
    Ivorian Chocolate Makers Promote Locally-made Chocolatei
    X
    July 29, 2016 4:02 PM
    Ivory Coast is the world's top producer of cocoa but hardly any of it is processed into chocolate there. Instead, the cocoa is sent abroad to chocolate makers in Europe and elsewhere. This is a general problem throughout Africa – massive exports of raw materials but few finished goods. As Emilie Iob reports from Abidjan, several Ivorian entrepreneurs are working to change that formula - 100% Ivorian chocolate bar at a time.
    Video

    Video Ivorian Chocolate Makers Promote Locally-made Chocolate

    Ivory Coast is the world's top producer of cocoa but hardly any of it is processed into chocolate there. Instead, the cocoa is sent abroad to chocolate makers in Europe and elsewhere. This is a general problem throughout Africa – massive exports of raw materials but few finished goods. As Emilie Iob reports from Abidjan, several Ivorian entrepreneurs are working to change that formula - 100% Ivorian chocolate bar at a time.
    Video

    Video Tesla Opens Battery-Producing Gigafactory

    Two years after starting to produce electric cars, U.S. car maker Tesla Motors has opened the first part of its huge battery manufacturing plant, which will eventually cover more than a square kilometer. Situated close to Reno, Nevada, the so-called Gigafactory will eventually produce more lithium-ion batteries than were made worldwide in 2013. VOA's George Putic reports.
    Video

    Video Polio-affected Afghan Student Fulfilling Her Dreams in America

    Afghanistan is one of only two countries in the world where children still get infected by polio. The other is Pakistan. Mahbooba Akhtarzada who is from Afghanistan, was disabled by polio, but has managed to overcome the obstacles caused by this crippling disease. VOA's Zheela Nasari caught up with Akhtarzada and brings us this report narrated by Bronwyn Benito.
    Video

    Video Hillary Clinton Promises to Build a 'Better Tomorrow'

    Democratic presidential candidate Hillary Clinton urged voters Thursday not to give in to the politics of fear. She vowed to unite the country and move it forward if elected in November. Clinton formally accepted the Democratic Party's nomination at its national convention in Philadelphia. VOA national correspondent Jim Malone has more.
    Video

    Video Trump Tones Down Praise for Russia

    Republican presidential candidate Donald Trump is toning down his compliments for Russia and Vladimir Putin as such rhetoric got him in trouble recently. After calling on Russia to find 30.000 missing emails from rival Hillary Clinton, Trump told reporters he doesn't know Putin and never called him a great leader, just one who's better than President Barack Obama. Putin has welcomed Trump's overtures, but, as Zlatica Hoke reports, ordinary Russians say they are not putting much faith in Trump.
    Video

    Video Uganda Unveils its First Solar-powered Bus

    A solar-powered bus described by its Ugandan makers as the first in Africa has made its public debut. Kiira Motors' electric bus, Kayoola, displayed recently at a stadium in Uganda's capital. From Kampala, Maurice Magorane filed this report narrated by Salem Solomon.
    Video

    Video Silicon Valley: More Than A Place, It's a Culture

    Silicon Valley is a technology powerhouse and a place that companies such as Google, Facebook and Apple call home. It is a region in northern California that stretches from San Francisco to San Jose. But, more than that, it's known for its startup culture. VOA's Elizabeth Lee went inside one company to find out what it's like to work in a startup.
    Video

    Video Immigrant Delegate Marvels at Democratic Process

    It’s been a bitter and divisive election season – but first time Indian-American delegate Dr. Shashi Gupta headed to the Democratic National Convention with a sense of hope. VOA’s Katherine Gypson followed this immigrant with the love of U.S. politics all the way to Philadelphia.
    Video

    Video Dutch Entrepreneurs Turn Rainwater Into Beer

    June has been recorded as one of the wettest months in more than a century in many parts of Europe. To a group of entrepreneurs in Amsterdam the rain came as a blessing, as they used the extra water to brew beer. Serginho Roosblad has more to the story.
    Video

    Video Commerce Thrives on US-Mexico Border

    At the Democratic Convention in Philadelphia this week, the party’s presumptive presidential nominee, Hillary Clinton, is expected to attack proposals made by her opponent, Republican presidential nominee Donald Trump, to build a wall along the U.S.-Mexico border. Last Friday, President Barack Obama hosted his Mexican counterpart, President Enrique Peña Nieto, to underscore the good relations between the two countries. VOA’s Greg Flakus reports from Tucson.
    Video

    Video Film Helps Save Ethiopian Children Thought to be Cursed

    'Omo Child' looks at effort of African man to stop killings of ‘mingi’ children
    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.

    Special Report

    Adrift The Invisible African Diaspora