By Arthur Allen
It's just about impossible to predict what a flu virus is going to do. But history offers a critical guide anyway, showing public health officials which moves are likely to pay off in the battle against the disease.
1. What works: Shutting things down
In the so-called Spanish flu epidemic of 1918-1919, three waves of disease swept the world, killing approximately 50 million people, including 500,000 Americans. But Minneapolis and Milwaukee suffered fewer than 3 deaths per 1,000 people -- less than half the rate in cities like Baltimore, Boston, and San Francisco. One reason: The Midwestern cities quarantined the sick, closed schools and churches, and banned public gatherings. Another city, Gunnison, Colorado, escaped the plague by physically blocking the main roads into town. On the other hand, Philadelphia officials refused to ban meetings or parades on grounds of patriotism, and city newspapers downplayed the flu's severity. The result: Philly had one of the highest death rates in the country. These measures have a cost, of course: Closing schools could force so many parents to miss work that it could hamstring the economy. If the virus doesn't intensify, U.S. officials say, their advice is to keep schools open as much as possible.
Take-home lesson: Ask your kids' principal what would trigger a school closing, and be prepared. Strategize with friends about sharing child care if the need arises; talk to your boss about working from home.
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2. What works: Vaccinating kids early
Who gets flu shots in the United States? Old people, of course -- they've been the focus of flu vaccine campaigns since the 1960s. But an important way to increase their protection, ironically, is to vaccinate their children and grandchildren. The reason: An older person's immune system doesn't respond efficiently to the flu vaccine, so it's only partially protective. The same vaccine creates a much stronger immunity in the young. What's more, kids are more likely than others to become silent carriers, transmitting the virus for up to ten days after symptoms disappear.
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Take-home lesson: It's worth getting your family vaccinated even if the flu seems mild, if only because in some pandemics, the second wave has been deadlier than the first. The CDC advocates that children and young adults be among the first to receive the "panflu" vaccine. Some of the others on the priority list include people with chronic illnesses, like diabetes and heart or lung disease, and pregnant women, all of whom are at high risk from complications of the pandemic flu.
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3. What works: A vaccine that can't be fooled
Every year, people unlucky enough to be infected with the flu develop antibodies that will keep them safe if they're exposed to the same virus in the future. But gradually, the virus mutates -- sometimes enough to fool those antibodies and infect people again. As a result, virologists and public health officials are always playing catch-up. In February, they predict which strains of virus will circulate in the fall, and drug companies prepare vaccines to produce immunity to those specific strains. Inevitably, the predictions sometimes prove wrong. "It would be a huge advantage to have a universal vaccine," says E. John Wherry, PhD, of the Wistar Institute in Philadelphia -- a vaccine that would protect year in and year out, by aiming at pieces of the virus that don't change. Like hundreds of scientists around the world, Dr. Wherry is trying to develop such a vaccine. It's still a long way off, but a partial solution may already be available. When a vaccine is mixed with an adjuvant (a chemical mixture that stimulates the immune system), as has been done in studies of bird flu vaccine, it seems to protect against a variety of flu viruses. So even if the current virus mutates, an adjuvanted vaccine might still provide a shield.
Take-home lesson: Adjuvanted vaccines aren't licensed in the United States, and the Food and Drug Administration probably won't let us use them unless the virus becomes more serious. (However, there seems to be some natural cross-protection going on with this virus: Though new to human immune systems, it doesn't seem to infect people over 60 very often. Some earlier flu virus taught their immune systems a way to defend against the current one.) The best way to boost your protection: Wash your hands often-- the flu virus can survive up to 48 hours on surfaces. And get plenty of sleep; your immune system depends on it.
Plus: True Stories of the Swine Flu Pandemic
4. What works: A healthy respect for side effects
One balmy night in November 1976, 39-year-old June E. Roberts felt a coldness in her fingers as she tried to pay some bills. It was two weeks after she'd gotten a vaccine against the country's first outbreak of swine flu. The next morning, the McLean, Virginia, tennis instructor couldn't get out of bed. For more than a month, Roberts couldn't eat, move her limbs, or even close her eyes. She recovered, slowly, but was never able to play tennis well again. Roberts had Guillain-Barré syndrome, a disorder in which antibodies attack the patient's own nervous system. It was triggered by the flu vaccine she and more than 40 million other Americans had gotten. No one is entirely sure why the vaccine caused Guillain-Barré syndrome, but it affected more than 500 people and killed about 25. (The feared swine flu epidemic never materialized that year.) The episode highlights a point familiar to public health workers: Prevention never comes without risk.
Take-home lesson: The CDC is adding staff and computer tracking systems to look for possible problems with the vaccine, so if any unexpected dangers show up, they'll be flagged quickly. But experts emphasize that it's rare for any flu vaccine to have serious side effects, and they don't expect to see any with this vaccine. Specifically, they don't anticipate cases of Guillain-Barré syndrome, because of major differences between this year's swine flu virus and the one that prompted the 1976 vaccine.
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5. What works: Local control
Although you're hearing a lot from the CDC and the rest of the federal government -- not to mention the World Health Organization -- about how to respond to the flu, the real decisions will be made by states and localities. "Everything is local," says former CDC director David Sencer, MD. "The federal government can give guidance, but implementation has to be left to the local communities. Who are the key emergency workers to immunize, for instance? If you ask my daughter in Minneapolis, she'll say it's the snowplow driver. If you can't move around the city, you can't take care of sick kids." The downside is that with states, cities, and even school districts formulating their own policies, we're likely to hear conflicting advice.
Take-home lesson: Take a deep breath and get prepared for some confusion. To help sort things through, you can find helpful information at central clearinghouses: The federal government's is at flu.gov, and the CDC is tweeting updates at @CDCemergency.
Plus: Learn more about preventing colds and flu
By Arthur Allen