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Public Health

Flu Outbreak: The Early Line
Neil Wagner

May 01, 2009

An outbreak of swine flu has apparently begun. While much is being said about it, little is known so far. All U.S. cases to date have been mild.

Solid numbers can be hard to come by in this type of situation. There have been forty reported cases in the U.S.; the first twenty of these have already recovered. In Mexico, one report mentions 1,000 cases and eighty deaths; another, twenty-six cases and seven deaths. While the same virus appears to be responsible for cases in both countries, there’s no explanation for these different outcomes.

The Center for Disease Control has issued a few recommendations on how to avoid catching or spreading the flu. Wash your hands with soap and water. Cover your mouth and nose while coughing and sneezing. Avoid touching your eyes, nose and mouth. Avoid close contact with sick people. If sick, stay home from school or work. Staying in good general health is also helpful; this is not the best time to be pulling all-nighters or trying to live on junk food for a week.

When it comes to flu outbreaks, alarmists always point to 1918-19, while skeptics point to 1976. Reality usually lies somewhere in between.

In 1918-1919, an influenza pandemic (a pandemic is simply an epidemic on a global scale; it doesn’t imply anything about how deadly the infectious disease may be) killed 20-40 million people. This is often referred to as the Spanish flu. The current virus is similar to that virus in that both are H1N1 viruses. This isn’t much more meaningful than the fact that you and your last date had a lot in common because you were carrying human DNA. It’s just a single similarity.

In 1976, a threatened U.S. swine flu epidemic led to predictions of one million deaths. In reality, four or fewer people died. About 1,100 came down with a neurological disease, Guillain-Barre syndrome, as a side effect from specially prepared flu vaccine. This was a case where the cure was worse than the illness. That, too, was an H1N1 virus.

Flu virus is constantly changing (mutating). That’s why flu vaccine from one year is ineffective the next year. Usually the changes are small. When a large change occurs, this is known as a major antigenic shift. In such a case, human immune systems are not prepared for such a large change and are ineffective at fighting off the virus. This doesn’t happen very often but when it does, the flu becomes much more than a yearly annoyance. This is what health officials are always worrying about. There is at present no evidence that this is what is occurring right now.

More will be known about the current outbreak shortly. Right now, it’s just the flu.