|Watching Avian Influenza
November 2, 2005
A Calvin College biology professor is watching international reactions to avian influenza with interest.
Already U.S. President George W. Bush has asked for over $7 billion in emergency funding to fight an outbreak of the bird flu virus.
"There is no pandemic flu in our country, or in the world, at this time," Bush said in a speech at the US government-funded National Institutes of Health. "But if we wait for a pandemic to appear, it will be too late to prepare, and one day many lives could be needlessly lost because we failed to act today."
Calvin's Kathryn Jacobsen is an expert on international health and infectious disease epidemiology. She says government officials around the world are right to be worried about avian flu and a worldwide flu pandemic.
But, she notes, governments and individuals need to be smart about how they talk about the different kinds of bird flus currently in circulation and what those flus might mean to humans.
"There is no vaccine presently available for the current avian influenza," she says, "the influenza known as H5N1. Although vaccines against H5N1 influenza virus are in clinical trials, they are not yet commercially available and will not be ready for this flu season."
Also, says Jacobsen, the nature of flu viruses makes developing vaccines a tough task.
"Influenza viruses are constantly changing, which is why people need to get a new flu shot every year," she says. "Subtypes of influenza viruses differ in the way that their surface proteins - hemagglutinin (H) and neuraminidase (N) - appear. Most strains in recent decades have been H3N2. The current avian influenza is H5N1, and because this is a relatively new strain few people have natural immunity to it."
Jacobsen says that although the likelihood of a major pandemic within the next several years is very high, the probability of the current H5N1 strain mutating to become person-to-person transmissible this year is relatively small. If a pandemic does not occur for several years she says there may be time to develop, test, and produce an influenza vaccine effective against "bird flu."
But because there is no vaccine available now, Jacobsen says it makes sense to stockpile antivirals like Tamiflu and Relenza that can ease symptoms and shorten the duration of illness.
"Mathematical models of influenza spread have predicted that the use of targeted antivirals could make a significant contribution to containing an emerging influenza epidemic," she notes.
Indeed President Bush has proposed purchasing $1 billion worth of antiviral drugs like Relenza (zanamivir) and Tamiflu (oseltamivir) that can relieve symptoms of influenza.
But many media reports have misidentified the role of such drugs.
"These drugs are not vaccines," says Jacobsen, "although they may reduce the chance of becoming infected if the drug is taken when a person has a known exposure to influenza. The stockpile proposed by the President would be used to treat first responders and high-risk populations."
Jacobsen notes that everyone can take steps to prevent the spread of influenza, no matter what strain is circulating.
"Get a flu vaccine, wash your hands often, and, if you do get sick, stay home to avoid passing the virus on to classmates or co-workers," she says.
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