BANGKOK, Thailand – 1. Is a bird flu pandemic imminent?
Short answer: probably not. But there are many unknowns involved, making accurate prediction impossible.
Pandemic flu will happen sooner or later. It happens from time to time as new flu bugs emerge. These bugs cause global epidemics — pandemics — because humans have little or no immunity to these viruses. Sometimes, as in the war-torn world of 1918, it's a terrible plague. Sometimes, as in 1957 and 1968, it's relatively mild.
Bird flu is still a bird disease. The H5N1 bird flu in Asia does not spread well from person to person. It's a leading contender to be the next pandemic flu bug because it's caused an unprecedented epidemic in poultry and wild birds across Asia. But nobody knows for sure whether this will be the flu that causes the next human pandemic.
Bird flu could become a human flu in two ways.
—If a person were infected with a human flu and the bird flu at the same time, the two viruses could swap genes — reassort — and a human version of bird flu could emerge. This is what happened in the last two flu pandemics in 1957 and 1968.
—Bird flu could also evolve into a form adapted to humans, as happened in the 1918 flu pandemic. There's evidence the H5N1 bird flu virus has begun this process, but scientists say it isn't yet very far along.
At a World Health Organization news conference last May, Klaus Stöhr, PhD, DVM, project leader for the WHO's Global Influenza Program, was asked whether a bird flu pandemic is imminent.
"With this virus we have had very many surprises; we have had a very steep learning curve," Stöhr said. "We are seeing that it is changing very rapidly. We have also seen that it is not reassorting as everybody thought 18 months ago. So we do not know if a pandemic can occur next week or next year, or perhaps if another virus is going to cause a pandemic. We should simply continue with our pandemic preparedness."
2. Is there a cure for bird flu?
No. There's no cure for any kind of flu. However, antiviral drugs taken very soon after symptoms — such as a sudden fever — appear make the illness less severe. The H5N1 bird flu is resistant to an older class of flu drugs, but remains sensitive to Tamiflu and Relenza.
The H5N1 bird flu bug has been particularly deadly for people unlucky enough to catch it from poultry. But if the bug learns to spread among humans, it almost certainly won't be as deadly as it is now, says Ira Longini, PhD, professor of biostatistics at Emory University's Rollins School of Public Health.
"Avian H5N1 looks like a 70 percent case fatality in humans. But this has never been true of any human strain," Longini told WebMD last December. "There has never been any human influenza virus that has behaved that way in recorded or even unrecorded history. The case fatality of even highly virulent flu strains are a couple of deaths per 10,000 people."
3. What good are antiviral drugs?
Tamiflu and Relenza can be used both to treat and to prevent flu infections. Although the H5N1 flu has developed Tamiflu resistance in some treated individuals, this is not unexpected. And flu viruses resistant to Tamiflu don’t spread very well.
Vaccines, not antiviral drugs, are the key to stopping the flu. An experimental H5N1 vaccine has been made — a major scientific achievement. New ways of using it already are being tested.
But the first batch of this prototype vaccine likely will not be a good match for whatever bird flu virus eventually emerges to cause a pandemic. New batches of vaccine will have to be made. That process would take more than a year. Meanwhile, experts suspect that modern transportation would carry flu around the world.
Since a vaccine won't immediately be available, flu drugs will be a major line of defense. But there won't be enough of the drugs to go around.
4. Should individuals stock up on flu drugs?
No. Several flu experts tell WebMD that they are not stocking up on flu drugs, and they strongly recommend that individuals follow their lead.
Why? First of all, the drugs are in short supply. In the event of a pandemic, public health workers will need all the flu drugs they can get in order to treat people actually exposed to the virus. The drugs won't do nearly as much good sitting in people's medicine cabinets.
And even if you had the drugs on hand, when would you take them? Without a flu test, it's hard to know whether your symptoms are the flu or another respiratory infection. And the pills only work against the flu.
5. Can you get bird flu from eating chicken or other poultry?
No — if the meat is fully cooked. Cooking kills flu viruses in poultry, meat, and eggs.
The bird flu virus can survive on raw meat from infected poultry. Proper hygiene — hand washing and the disinfecting of all surfaces that come in contact with the meat — is essential.
6. How do you catch bird flu?
People have caught bird flu from handling infected poultry and from surfaces contaminated with poultry feces. There are a few suspected cases of human-to-human bird flu transmission. This happened only after prolonged face-to-face contact. But bird flu has not learned how to spread easily from person to person.
7. Is there more than one type of bird flu?
Yes. The H5N1 bird flu gets a lot of attention because it is so widespread in Asia, and because most of the people unlucky enough to catch it from poultry have died.
Other bird flu bugs have spread to humans. One is the H7N7 bird flu that in 2003 infected a number of people in the Netherlands. This virus usually caused pinkeye in infected people. However, one unlucky veterinarian died from the virus. Fortunately, Dutch authorities stamped out the virus before it learned to spread widely in humans.
Bird flus have, in the past, infected U.S. poultry. So far, all of these bugs have been eradicated before spreading among humans.
8. What can I do about bird flu? What can the government do?
If a bird flu pandemic occurs, there's a very good way to minimize the chance of getting infected: Wash your hands. Frequent hand washing is the best way to avoid a viral infection — including the flu. Remember to use soap and warm water, and to scrub all parts of the hand. The rule of thumb, as it were, is to scrub the hands and fingers until you finish singing the alphabet song to yourself.
Should a flu pandemic break out, pay attention to news reports, and follow public health advisories. Panic is the least helpful response to any emergency.
The U.S. is finalizing its pandemic flu preparedness plan. This will include plans for deciding which people most urgently need scarce hospital beds and medicines, deploying response teams, increasing hospital capacity, and, when necessary, enforcing patient isolation and quarantine. In an emergency situation, it may be necessary to close schools and public gathering places such as movie theatres.
When vaccines become available, health and public-safety workers and the most vulnerable people will get them first. Scarce flu drugs would be used to treat serious infections. If supplies permit, they would also be given to close contacts of infected people.
9. Who is most vulnerable to bird flu?
Flu is usually most dangerous to young children and to the elderly.
But a lot depends on whether there's any immunity to the flu in some populations. For example, the 1918 flu was more deadly to young adults than to those over 40. It's thought that a similar virus may have circulated more than 40 years before, giving some immunity to those who caught it.
10. How many people have caught bird flu so far?
As of Oct. 10, 2005, the World Health Organization reports 117 confirmed cases of H5N1 bird flu in humans. Sixty of these people have died.
These deaths are tragic. But many millions of birds have been infected with the virus in some of the most populous regions of the world. Even though confirmed infections no doubt represent a fraction of the total infections, people run a very low risk of catching the virus from poultry.
SOURCES: World Health Organization. CDC. WHO news conference, May 19, 2005: Klaus Stöhr, PhD, DVM, project leader, Global Influenza Program, WHO, Geneva. Ira Longini, PhD, professor of biostatistics, Rollins School of Public Health, Emory University; interviewed Dec. 1, 2004. Jeremy J. Farrar, MD, PhD, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam; interviewed Feb. 22, 2005. Frederick G. Hayden, MD, professor of clinical virology and internal medicine, University of Virginia, Charlottesville; interviewed September 27, 2005. Stephen Morse, PhD, founding director and senior investigator, Center for Public Health Preparedness, Mailman School of Public Health, Columbia University, New York; interviewed September 27, 2005. John Treanor,professor of medicine and director, vaccine and treatment evaluation unit, University of Rochester, N.Y.; interviewed September 27, 2005. Anne Moscona, MD, professor of pediatrics and microbiology and immunology, Weill Medical College of Cornell, New York; interviewed September 27, 2005. Anthony Fauci, MD, PhD, director, U.S. National Institute of Allergy and Infectious Diseases; interviewed Aug. 8, 2005.