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  • New bird flu vaccine?

    High hopes for bird flu jab

    <!-- A leading AIDS researcher is testing a new bird flu vaccine on mice, hoping to discover one capable of covering a wide range of influenza viruses to prepare for a possible pandemic.

    //-->
    Mimi Lau

    Monday, March 05, 2007

    <TABLE cellSpacing=0 cellPadding=9 width=250 align=right border=0 vAlign="top"><TBODY><TR><TD></TD></TR></TBODY></TABLE>A leading AIDS researcher is testing a new bird flu vaccine on mice, hoping to discover one capable of covering a wide range of influenza viruses to prepare for a possible pandemic.

    David Ho Da-yi, who is famous for his cocktail therapy for treating HIV, will elaborate on the progress of his bird flu vaccine research at an international medical forum at Hong Kong University today.
    He hopes that, with the positive results he has obtained from mice, he will be able to produce a vaccine which protects humans from many strains of the H5 virus.
    Speaking in Hong Kong Sunday, Ho said his New York-based laboratory is analyzing all available H5N1 sequencing to track down a consensus sequence to formulate new vaccines via two different approaches, DNA and proteins, to offer cross immunity protection against various strains of H5.
    "Basically, it would stimulate the body to generate an immune response to protect itself from the deadly influenza," Ho said, adding that the approach is easy, cheap and fast to produce while requiring only one shot to achieve immunization.
    "If you know what strain is likely to cause the pandemic, you can just take that strain to make the vaccine. But if you guess it wrong, big trouble.
    "The H5N1 is so widespread right now, it has to be one of the viruses we're worrying about," he said.
    According to Ho, the new vaccine has the potential to be made in one week and it will be very cheap "for governments to buy for the entire population."
    Ho added that should positive results come from testing on mice, ideally, the new vaccine could offer protection from different H5N1 viruses found in China, Vietnam or Indonesia, allowing a quick response during a pandemic.
    "Because when a pandemic comes, you want all the properties to be in one vaccine," Ho said.
    Commenting on the old technique where a vaccine is generated by injecting the influenza virus into an embryonic egg, Ho said although the method does work, it is slow, cumbersome and expensive.
    Currently, US pandemic preparedness is focused on vaccine technology instead of relying entirely on the old technique.

    "Once we have the results in experimental animals, it will take six to nine months to produce for human use, but it will take another several months for regulatory agencies to approve, such as FDA [Food and Drug Administration] in the United States, before running clinical trials on humans," Ho said.

    "It's not going to be very quick," he said, but stressed that "it's prudent to be prepared."

    He added: "I'd say the flu pandemic is going to come. We just don't know when."

    Looking back at the Katrina hurricane disaster in New Orleans in 2005 and the Indian Ocean tsunami in 2004, which showed that preparedness was lacking, Ho said: "This would be one of the best investments that the human race will make in new technology to allow us to come up with a vaccine for the pandemic. We should not make the same mistakes we have made repeatedly with other disasters."
    He said: "I think we should do it as soon as possible ... the sooner we're ready, the better prepared we will be.
    "We know how bad H5N1 is among birds today, it's only a few mutations away before that virus can be effectively transmitted to humans. So statistics would tell us it's only a matter of time. This is a real threat."
    Once the tests on animals show positive progress, Ho said he will extend them to human beings.
    Ho leaves for Beijing tomorrow to discuss HIV treatment and vaccines in general with mainland health officials.
    Local microbiologist Lo Wing-lok said he would be cautious about Ho's research as there are other concerns involved. He said even if the new vaccine is developed the question remains as to whether it would be widely available. Lo is concerned whether some of the world's poorest countries with the highest risk of a flu pandemic, such as Vietnam and Indonesia, could benefit from the technology in an emergency.
    Last edited by sharon sanders; March 4, 2007, 04:20 PM. Reason: format

  • #2
    Re: New bird flu vaccine?

    <TABLE cellSpacing=0 cellPadding=0 width="70%" border=0><TBODY><TR><TD vAlign=top align=left>

    <BASEFONT><!-- end aa_page_header --><!-- munch_heading: --><TABLE class=memberImgAndQuote cellSpacing=0 cellPadding=0 border=0><TBODY><TR><TD vAlign=top width="50%"> </TD></TR></TBODY></TABLE><TABLE class=memberText border=0><TBODY><TR><TD vAlign=top align=left width=400>Profile: David Ho
    AIDS Research Pioneer



    Back to David Ho Profile
    </TD></TR></TBODY></TABLE><!-- end munch_heading --><AA_HEADING>"My father left Taiwan to come to the United States to pursue graduate studies in engineering. So my brother and I were left in my mother's care, and in essence we grew up in Taiwan without my father being present."
    When David Ho was 12 years old, his father sent for the family to join him in a land they did not know, and whose language they did not speak. David was laughed at by classmates who thought he was stupid because he could not speak English, but he focused on his studies and was soon earning A's in math, science, and even English. After graduating summa cum laude from Cal Tech, he earned a scholarship to Harvard Medical School.
    As a young physician he saw some of the first known cases of AIDS. His pioneering work with "cocktails" of protease inhibitors and other antiviral drugs has brought about remarkable recoveries, and raised hope that the virus may someday be eliminated. Now Dr. David Ho is Director of the Aaron Diamond AIDS Research Center. He was chosen by Time Magazine as its 1996 "Man of the Year" for his discoveries.







    </BASEFONT></TD></TR></TBODY></TABLE>

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    • #3
      Re: New bird flu vaccine?

      Bird flu breakthrough could halt pandemic says expert
      39 minutes ago


      Researchers in the United States believe they have found an easily-produced vaccine for the killer H5N1 bird flu that could halt a feared pandemic, a media report said Monday.
      Dr David Ho of the Aaron Diamond Aids Research Centre in New York says the vaccine would be "easy to produce, fast to produce and as broadly protective as possible", according to Hong Kong's South China Morning Post newspaper.
      Ho spoke to the English-language daily during a lecture visit to Hong Kong, where the first human cases of H5N1 infection were recorded in 1997, when six people died.
      The report said tests on mice had shown the animals had produced the antibodies necessary to fight the disease, which has killed more than 160 people since outbreaks in Asia in 2003 spread throughout the world.
      While the virus has decimated poultry flocks, it cannot yet transfer efficiently enough between humans for it to spark a pandemic.
      But as the virus is mutating all the time, health experts fear the day when it does become easily transmitted is not far off. A pandemic would then claim millions of lives, they warn.
      The report says Ho claims to have overcome the problem of manufacturing enough of the vaccine to get it out fast enough to halt a pandemic.
      It said the process involves copying genetic material from flu virus protein and combining it with antibodies to help stimulate the immune system.
      The technique could be easily applied to other forms of flu virus too, it added.
      "These days gene synthesis and cloning can be done in a week so you just substitute the genes and use the same technology," Ho was quoted as saying.


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      • #4
        Re: New bird flu vaccine?



        SCIENCE NEWS
        March 06, 2007
        Bird Flu Buster: New Vaccine Protects against Multiple Viral Strains
        A drug company announces it has tested a vaccine that appears to protect against the different forms bird flu might take, which could be the key to preventing a pandemic
        By David Biello

        ONE SHOT: A few doses of a new vaccine may confer protection against a variety of bird flu strains.
        Every winter the seasonal flu vaccine gets reformulated. The World Health Organization recommends which viruses to put into the vaccine to impart immunity against the strains that are considered most likely to spread. For example, this year's vaccination cocktail will include the antigens isolated from flu strains first spotted in the Solomon Islands, Wisconsin and Malaysia. This continual updating results from the flu virus's ability to mutate in response to the human body's immune defenses. This ability to mutate and spread quickly also lurks at the core of pandemic fears surrounding bird flu, but a new vaccine formulation tested in ferrets and human blood appears to confer protection against a variety of mutated avian influenzas.

        Researchers from GlaxoSmithKline (GSK) at the IX International Symposium on Respiratory Viral Infections in Hong Kong this week revealed that a new vaccine that had previously proved effective in protecting people against a strain of H5N1 bird flu from Vietnam also protected them from another bird flu variant isolated in Indonesia. "These two strains, when evaluated for antigenic relatedness, showed an eight- to 16-fold difference for a reference antiserum," says Bruce Innis, vice president and director of clinical research and development and medical affairs at GSK Biologicals. In other words, the vaccine protected the blood from 400 volunteers from two very different strains of bird flu.

        Most vaccines only work against the virus they are specifically designed to fight. "When you get vaccinated with a flu vaccine, your antibody response tends to be narrowly directed at the virus that was targeted by the vaccine," explains John Treanor, an immunologist at the University of Rochester. "When we're vaccinating against pandemic flu, with no prior exposure, you would expect the response to be narrowly focused." Yet, in blood tests, the GSK vaccine effectively neutralized both the Vietnamese and Indonesian strains.

        Further tests in ferrets showed that a propriety adjuvant system?extra agents such as aluminum salts in a vaccine that enhance its effectiveness?may be behind the effect. Animals given the Vietnam vaccine without the adjuvants died after being exposed to the Indonesian strain. "All of the control animals died and the great majority [(22 out of 23)] of the vaccinated animals survived," Innis says. "Is it the adjuvant system that is producing the protective effect? In our view, the answer is yes."

        Exactly how the adjuvant system works remains a mystery as well?even more so because GSK will not reveal what adjuvant system it used, revealing only that there are 25 new adjuvants being analyzed. "Does it somehow cause a whole new spectrum of shapes on the surface proteins of the flu virus to be recognized? Or does it increase the amplitude of the immune response?" Innis asks. "Those tests haven't been done yet, but effects that are present at very low doses with the adjuvant system are almost completely absent at eight times that dose without the adjuvant system." Its effectiveness is clear: the immune response in human blood was 25 times stronger with the adjuvant present than without it.

        This raises the prospect that the new vaccine could cut down on the amount of antigen required to manufacture it as well as confer broader protection?without the need for reformulation. The U.S. Department of Health and Human Services has already contracted with GSK for $40 million worth of antigens to the Indonesian strain with an option to purchase the mysterious adjuvant system, too. This could lead to the ability to stockpile an effective vaccine against the much-feared potential bird flu pandemic. As Treanor says: "Since you don't know which one, if any, of the bird flu strains might emerge as the pandemic strain, there is some advantage in an antibody that might be able to affect members of multiple strains."

        Innis adds: "We know that the job of flu vaccine is to protect against not only what you put in the vaccine but also things that might occur in the future because [evolution] is ongoing."

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