Frequently Asked Questions About Bird Flu
What Are the Symptoms of Bird Flu in Humans?
Bird flu symptoms in people can vary. Symptoms may start out as normal flu-like symptoms. This can worsen to become a severe respiratory disease that can be fatal.
In February 2005, researchers in Vietnam reported human cases of bird flu in which the virus infected the brain and digestive tract of two children. Both died. These cases make it clear that bird flu in humans may not always look like typical cases of flu.
Bird Flu's Worst-Case Scenario
If a person -- or a susceptible animal -- gets infected with bird flu and human flu at the same time, the bird and human flu viruses could swap genes. Even without swapping genes, H5N1 could mutate into a form that more easily infects humans.
The lab-created H5N1 mutants remain in high-security labs. But the mutations needed to make H5N1 an airborne, human virus already exist in H5N1 viruses seen in nature. So far, the full set of mutations has not appeared in the same virus.
It would be bad news if H5N1 were to become as contagious as human flu. If it remained as lethal as it is now, the fatality rate would be about 58%. The deadliest flu bug in history, which caused the 1918 Great Pandemic, had a fatality rate of 2%.
Even if it's a relatively mild new flu virus, it could spread rapidly across the globe. That's because most humans would have no immunity to the new kind of flu. During the 20th century, this happened three times.
But just because it happened before doesn't mean it will happen this time. While experts say it's inevitable that sooner or later we'll see another flu pandemic, it's by no means certain that the current bird flu virus will be the cause.
Even if a new human flu emerges, public health officials might be able to contain it. H5N1 is susceptible to the newer flu drugs. And a vaccine already has been created and stockpiled by the World Health Organization.
Is There a Bird Flu Vaccine?
Yes. On April 17, 2007, the FDA announced its approval of the first vaccine to prevent human infection with one strain of the bird flu. The vaccine has been purchased by the U.S. federal government to be distributed by public health officials if needed. This vaccine will not be made commercially available to the general public.
Other bird flu vaccines are being developed by other companies. And the World Health Organization has a stockpile of the vaccine, with plans to quickly produce more if needed.
When given along with immunity-boosting agents called adjuvants, experimental H5N1 vaccines offer good cross-protection against different H5N1 variants.
And several companies are working on universal flu vaccines and antivirals that would protect against all known strains of influenza.