The news is alarming: Avian influenza, or bird flu, has spread from Asia to livestock populations in Eastern Europe. At least 60 human deaths have been associated with avian flu, and more than 100 million birds have either died from the disease or been killed in efforts to contain it.
With such scary statistics and memories of last year's flu-shot shortage fresh in their minds, it's no wonder parents are concerned. But what are the real risks, and what -- if anything -- can people do to protect their families? In an exclusive interview, we asked Paul A. Offit, M.D., chief of infectious diseases at The Children's Hospital of Philadelphia and co-author of Vaccines: What You Should Know, to help put the threat of an avian-flu pandemic in perspective.
Avian flu, which is carried by all types of birds, is especially lethal in domesticated fowl such as chickens, ducks, and turkeys. The first case of bird-to-human infection occurred in Hong Kong in 1997, according to the Centers for Disease Control and Prevention (CDC) in Atlanta, and led to 18 human cases resulting in six deaths. Despite containment efforts, the virus cropped up again in 2003 and has demonstrated unusual staying power, causing several dozen more human fatalities throughout Asia. (To date, the U.S. has had no reported cases of the virus.)
Does avian flu pose a widespread threat to humans? Perhaps -- but first it must become more contagious among people. "We've seen that once birds are infected, they die in great numbers, and they die quickly," says Dr. Offit. "Fortunately, avian flu remains difficult for people to catch." The bad news, however, is that once people are infected, the effects of avian flu can be serious. "Unlike garden-variety strains of influenza that people contract every year, avian flu is new to the human population," says Dr. Offit. "So our immune systems are ineffective in fighting it without treatment."
Infected birds shed flu virus in their saliva, nasal secretions, and feces, according to the CDC. The virus spreads when susceptible birds make contact with contaminated secretions or surfaces. Humans contract avian flu through direct contact with contaminated materials, says Dr. Offit. "Not surprisingly," he says, "most people infected with avian flu were poultry workers." There is no evidence humans can contract the virus from eating contaminated poultry products.
With fewer than 150 human cases of avian flu reported worldwide, Dr. Offit believes there's little reason American families should be concerned right now. "All human cases so far -- with the possible exception of one -- have resulted from contact with infected livestock," he says. "And you can't have a pandemic without extremely efficient person-to-person transmission."
At this time it is safe to travel internationally, according to the CDC. If your family plans to visit an area affected by avian flu, the agency recommends avoiding contact with animals in live food markets as well as poultry farms.
This doesn't mean, however, that governments and health officials are off the hook when it comes to creating a solid emergency-management plan. "The United States and the world are woefully unprepared for an avian-flu-style pandemic," Dr. Offit says. "Since only a handful of pharmaceutical companies manufacture flu vaccines today, it would be years before there were enough doses for everyone." To complicate matters further, companies can't even begin manufacturing a vaccine until avian flu becomes clearly contagious among humans, since researchers need to isolate the specific strain causing the illness. (Regular flu shots are not effective in preventing avian flu.) With respect to Tamiflu, an antiviral medication designed to reduce flu symptoms and rates of transmission, perhaps including those of avian flu, Dr. Offit says caution is in order. "It's important to remember that Tamiflu is not a vaccine," he says. "Unlike an avian-flu vaccine, which would work for an entire season, Tamiflu is effective only while you're taking it. So though it would certainly help during an avian flu pandemic, it shouldn't be our only line of defense." What's more, because the threat of an outbreak appears slight, there is no reason for families to stockpile or begin taking Tamiflu for preventive reasons.
"What we need to do is change how vaccines are produced, so in the event of an avian flu outbreak we'd be able to generate doses more quickly." He adds: "I'm in Philadelphia, so I'd be remiss if I didn't offer at least one Ben Franklin quote: 'An ounce of prevention is worth a pound of cure.' That could make all the difference."
Research from scientists at the CDC suggests that the 1918 "Spanish flu" virus, which killed up to 50 million people worldwide, probably originated in birds. Would an outbreak of avian flu today be as devastating? It's impossible to say, but Dr. Offit feels we can do much to offset the effects of a pandemic. "Living conditions are more sanitary today than they were in 1918," he says. "Medical science is better. Small gestures -- like washing your hands, limiting contact with sick people, even wearing masks -- would probably help prevent infection in the unlikely event of an outbreak."
Of far greater concern for families, says Dr. Offit, are standard flu viruses that sweep the country. "Thirty-six thousand people in the U.S. die from regular influenza every year," he says. "And those are viruses for which vaccines are readily available." Shots for seasonal influenza are safe for children ages 6 months and older; a nasal-spray flu vaccine is approved for children ages 5 and older. Children younger than 9 years receiving the flu shot for the first time require two doses 30 days apart; children vaccinated in previous years need only one dose.
"That should be the priority for parents," Dr. Offit says. "After all, avian flu is just a potential threat; seasonal influenza is already here."