The H1N1 flu was a surprise right from the start: a soon-to-be pandemic flu virus that was first identified in kids in the United States. But that's not the only unusual fact about H1N1 flu. Here are eight more surprising developments:
women are more likely to be hospitalized and are at higher risk of death and complications from flu, including swine flu and seasonal flu, than the general population. As scary as that sounds, experts say that most pregnant women who become ill with H1N1 swine flu will not have a serious problem. If you are pregnant, here's what you need to know.
In April 2009, CDC researchers met to name the newly identified flu virus. The virus came to humans via swine, so the first idea was to call it swine influenza virus. But SIV already stands for simian immunodeficiency virus. Some CDC wags had fun coming up with less serious names: Swine-09, pandemic influenza generating virus (PIG-V), snoutbreak virus, and aporkalypse virus. Sadly for comedians, the CDC finally settled on 2009 H1N1 virus.
2 Is this thing broken?
Scientists in the United States first discovered the swine flu virus -- but it was something of a fluke. Navy and CDC researchers were testing an experimental device designed to tell which type of flu virus, if any, was in a nasal swab sample from a sick child. One of the first 25 samples tested came up untypeable. "We thought, 'This device sucks,'" recalls Dan Jernigan, MD, MPH, deputy director of the CDC's flu division. But lab tests showed they'd actually been the first to identify the 2009 H1N1 flu virus.
3 What scares the CDC about H1N1
What keeps CDC officials up at night is the specter of the 1918 flu pandemic. In the United States, this deadliest-ever pandemic began with a spring wave of relatively mild flu -- a lot like the 2009 H1N1 flu in this country last spring. But when the weather got cool, the flu turned cruel: In the fall and winter of 1918 to 1919, two waves of much more deadly disease swept the nation. Although pandemic flu has stayed relatively mild in 2010, CDC officials slept a little better -- but they're still sleeping with one eye open.
4 The swine flu nightmare scenario
Remember the H5N1 bird flu? It's still out there and it's still a killer. Fortunately, the virus does not (yet) transmit easily from person to person. An H5N1 pandemic would be terrible. The United States is already stockpiling a vaccine just in case. In case of what? The H1N1 flu virus learned to infect humans by swapping genes with other flu viruses. That could happen again -- if someone gets infected with the pandemic H1N1 bug and the H5N1 bird flu bug. "We are in a double jeopardy situation where H5N1 has little or no capacity to transmit among humans, while H1N1 has great capacity," flu expert Robert Webster, PhD, said at a June 2009 meeting. "Will it pick up this enormous pathogenicity of H5N1? God help us if it does."