The Avian Flu Vaccine
The ]]>bird (or avian) flu]]> is a respiratory infection caused by the H5N1 virus. The virus is common among wild birds and usually does not cause any symptoms. But, it can be deadly in domesticated poultry, like chicken and turkeys.
While the virus rarely infects people, in 1997, there was an H5N1 outbreak in Hong Kong—18 people became ill and six died. Since then, the bird flu has infected people in over 15 countries in Asia, Europe, the Near East, the Pacific, and Africa. According to the World Health Organization (WHO), 395 confirmed cases and 250 deaths occurred between 2003-2008. People at the greatest risk are those who have direct contact with sick or dead birds or with surfaces contaminated by the virus. There have been a few cases, though, where the virus spread between people.
Health officials and researchers anticipate that the virus will reach new areas, especially with H5N1 infecting migratory birds. An even greater threat is that the virus could mutate into a more contagious form, with the ability to spread more easily from birds to people and between people. If this were the case, the bird flu could become a pandemic, like the 2009 outbreak of ]]>swine flu]]> (H1N1) that has spread to at least 155 countries and territories. While most cases of H1N1 are relatively mild (similar to the ]]>seasonal flu]]> ), the bird flu can quickly progress to life-threatening ]]>pneumonia]]> and other serious complications, even among young and middle-aged healthy individuals.
What’s the Current Status of the H5N1 Vaccine?
Antibodies are the body’s natural defense against infection. ]]>Vaccines]]> work by triggering the body to make specific antibodies to a particular virus. If a person who has been vaccinated becomes infected with the virus, the antibodies quickly destroy it.
Research studies in humans began in 2005 to evaluate vaccines to prevent avian flu. In 2007, the US Food and Drug Administration (FDA) approved the first US vaccine to protect against a strain of the virus. The vaccine is intended for people aged 18-64 who have an increased risk of exposure to H5N1. Adults receive a series of two shots that are given one month apart.
The vaccine, though, is not available to the general public. The US government purchased it for the Strategic National Stockpile, where large supplies of medicines are stored in case of a national emergency. According to the Infectious Diseases Society of America, the US currently has about 26 million doses of the vaccine. Other countries also have stockpiles, and the WHO has plans to create a 150 million worldwide stockpile. One major issue that governments are facing is that, with a two-year stock life, some of these doses have already expired. But, it’s estimated that at least 16 companies are developing a new H5N1 vaccine to better prepare the world for a bird flu pandemic.
For example, the company Novartis has developed a vaccine called Aflunov that uses an adjuvant, a substance that triggers the immune system to have a stronger response. In investigational studies, Aflunov has shown to offer protection against several H5N1 strains. Another company, BioSante Pharmaceuticals, is currently conducting tests on two vaccines—one for swine flu and one for bird flu—that use its new adjuvant BioVant, designed to make the vaccines more effective.
What Are the Other Options in Case of an Outbreak?
While researchers work toward protecting the population from H5N1, there are steps you can take to reduce your risk of becoming sick. For example, avoiding direct and indirect contact with wild and domestic birds and making sure all poultry foods are thoroughly cooked are just two ways you can lower your chance of contracting the virus.
In addition, medications used to treat and prevent the seasonal flu may be effective against avian flu. ]]>Oseltamivir]]> (Tamiflu) is currently recommended for the treatment and prevention of H5N1, but there have been some cases where the virus was resistant to this medication. The major issue facing health agencies is that the strain of H5N1 could mutate to become more contagious and less responsive to medications.
While the world’s attention has been focused on creating a vaccine for the current H1N1 pandemic, the bird flu remains a threat and an area of intense research.
Centers for Disease Control and Prevention (CDC)
World Health Organization (WHO)
Canadian Lung Association
Public Health Agency of Canada
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Novartis MF59-adjuvanted vaccine rapidly induces protective antibody levels against diverse strains of avian flu. Norvartis website. Available at: http://www.novartis.com/newsroom/media-releases/en/2008/1252754.shtml . Published September 19, 2009. Accessed August 20, 2009.
Novartis investigational adjuvanted (MF59) pre-pandemic avian influenza vaccine Aflunov shows long lasting, broadly cross protective immune response. Norvartis website. Available at: http://www.novartisvaccines.com/downloads/newsroom/media-releases/novartis_investigational_adjuvanted.pdf . Published April 30, 2009. Accessed August 20, 2009.
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Strategic national stockpile (SNS). Centers for Disease Control and Prevention website. Available at: http://www.bt.cdc.gov/stockpile/ . Updated March 2009. Accessed August 4, 2009.
Last reviewed August 2009 by ]]>Richard Glickman-Simon, MD]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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