News / Health

    Study Reveals Chink in Polio Vaccine’s Armor

    A boy suffering from polio crawls beside his braces in Kinshasa, capital of the Democratic Republic of the Congo, November 29, 2011.
    A boy suffering from polio crawls beside his braces in Kinshasa, capital of the Democratic Republic of the Congo, November 29, 2011.

    A mutated polio virus that slipped through vaccine defenses caused an unusually lethal outbreak in the Republic of Congo in 2010, according to a new study. 

    An intensive vaccination campaign was able to stop the virus. 

    But the authors say their research shows new and dangerous strains may emerge as polio eradication nears, and high rates of vaccination are the best available protection.

    Weaker vaccine

    Polio usually paralyzes its victims. It is not typically fatal. But in the Republic of Congo outbreak, nearly half of the 445 people who got sick with the virus died. 

    Health workers were especially concerned because about half of the patients remembered having been vaccinated. 

    “That made it even more bizarre, because if they had been vaccinated, they shouldn’t be sick,” said virologist Felix Drexler at the University of Bonn.

    When Drexler and colleagues in Europe and Africa studied the virus, they found it had some never-before-seen mutations in a critical part of its outer coat. Those mutations were in the place where antibodies that fight the virus would normally attach.

    “We thought, ‘Wow, maybe that could affect the ability of the antibodies in human blood to neutralize the virus,’” Drexler said. 

    It did. When they tested the virus in Germany against blood samples from people with better-than-average vaccination coverage, they found that 15 to 29 percent of them would not be protected from the mutant strain.

    The research is published in the Proceedings of the National Academy of Sciences.

    Virus stopped

    The Republic of Congo had been polio free before the outbreak. It took four nationwide immunization drives targeting every man, woman and child to stop the mutated virus. 

    Drexler said the effort worked because just about everyone got vaccinated with the most potent form of the vaccine. 

    The virus has not been seen since, though Drexler said it’s possible it’s still lurking out there somewhere. And, he added, there may be others that also can evade the vaccine's protection. 

    Experts say polio eradication is in its final stages. There have been fewer than 150 cases anywhere in the world this year, and the virus is found regularly in just three countries. 

    Good enough?

    But, Drexler noted, “The question that the experts are asking is, 'Is the vaccine good enough to enable us to eradicate poliovirus?'”

    Virologist Olen Kew with the U.S. Centers for Disease Control and Prevention says it is. He was not involved with this study. He noted that the vaccine has eliminated the virus everywhere it has been used.

    “What happened in Congo was, it hadn’t been used for quite a long period of time and a susceptible group opened up,” he said. Civil unrest disrupted vaccination campaigns in the 1990s and early 2000s. “And when the virus was introduced, it had devastating effects.”

    Kew said the reason the virus was so deadly was because the susceptible group was young adults, not the children who are usually affected. 

    “It’s been known for a long time that older age groups, once they get infected, can have more severe disease than younger children,” he said.

    Associate Director Walt Orenstein at the Emory Vaccine Center, who was also not involved in the study, said more potent vaccines would be helpful to protect against mutated viruses.

    However, he added, “I think the most important message, to me, is, we need to push hard and push fast and terminate transmission as quickly as possible, in which case this becomes irrelevant.”


    Steve Baragona

    Steve Baragona is an award-winning multimedia journalist covering science, environment and health.

    He spent eight years in molecular biology and infectious disease research before deciding that writing about science was more fun than doing it. He graduated from the University of North Carolina at Chapel Hill with a master’s degree in journalism in 2002.

    You May Like

    Video Democrats Clinton, Kaine Offer 'Very Different Vision' Than Trump

    In a jab at Trump, Clinton says her team wants to 'build bridges, not walls'; Obama Hails Kaine's record; Trump calls Kaine a 'job-killer'

    Turkey Wants Pakistan to Close Down institutions, Businesses Linked to Gulen

    Thousands of Pakistani students are enrolled in Gulen's commercial network of around two dozen institutions operating in Pakistan for over two decades

    AU Passport A Work in Progress

    Who will get the passport and what the benefits are still need to be worked out

    This forum has been closed.
    Comment Sorting
    Comments
         
    by: eusebio from: Portugal
    August 20, 2014 12:42 PM
    Stop Pólio in DRCongo sustainable solutions in the areas of the fight against Pólio

    Featured Videos

    Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
    In State of Emergency, Turkey’s Erdogan Focuses on Spiritual Movementi
    X
    July 22, 2016 11:49 AM
    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 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 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 Poor Residents in Cleveland Not Feeling High Hopes of Republican Convention

    With the Republican Party's National Convention underway in Cleveland, Ohio, delegates and visitors are gathered in the host city's downtown - waiting to hear from the party's presidential candidate, Donald Trump. But a few kilometers from the convention's venue, Cleveland's poorest residents are not convinced Trump or his policies will make a difference in their lives. VOA's Ramon Taylor spoke with some of these residents as well as some of the Republican delegates and filed this report.
    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 With Yosemite as Backdrop, Obama Praises National Parks

    Last month, President Barack Obama and his family visited some of the most beautiful national parks in the U.S. Using the majestic backdrop of a towering waterfall in California's Yosemite National Park, Obama praised the national park system which celebrates its 100th anniversary this year. He talked about the importance of America’s “national treasures” and the need to protect them from climate change and other threats. VOA’s Julie Taboh reports.
    Video

    Video Counter-Islamic State Coalition Plots Next Steps

    As momentum shifts against Islamic State in Iraq, discussions are taking place about the next steps for driving the terrorist group from its final strongholds. Secretary of State John Kerry is hosting a counter-IS meeting at the State Department, a day after defense ministers from more than 30 countries reviewed and agreed upon a course of action. VOA Pentagon correspondent Carla Babb reports.
    Video

    Video Russia's Participation at Brazil Olympic Games Still In Question

    The International Olympic Committee has delayed a decision on whether to ban all Russian teams from competing in next month's Olympic Games in Brazil over allegations of an elaborate doping scheme. The World Anti-Doping Agency recently released an independent report alleging widespread doping by Russian athletes at the 2014 Winter Olympics in Sochi. So far, only Russian track and field athletes have been barred from the Summer Games in Brazil. VOA's Zlatica Hoke 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.
    Video

    Video Millennials Could Determine Who Wins Race to White House

    With only four months to go until Americans elect a new president, one group of voters is getting a lot more attention these days: those ages 18 to 35, a generation known as millennials. It’s a demographic that some analysts say could have the power to decide the 2016 election. But a lot depends on whether they actually turn out to vote. VOA’s Alexa Lamanna reports.

    Special Report

    Adrift The Invisible African Diaspora