A year ago today, Lyn Finelli, chief of flu surveillance at the Centers for Disease Control and Prevention, gathered her team and advised them to prepare for the worst.
A flu epidemic was brewing, Finelli said, caused by a virus never before seen in humans. In Mexico, hospital workers were sick and dying. "That scared all of us," she says now, because "we all know from SARS and Ebola what a red flag it is" when health workers who guard against infection fall ill themselves. "It means the virus is very contagious and very virulent."
"I want everyone to call your families," she said. "Tell them that they're not going to be seeing you much for a while. We're going to have to work hard for the next few months to figure this out."
This is the story of those early efforts. A year has passed since epidemic experts began tracking the birth of the 2009 H1N1 swine influenza pandemic. Now that swine flu has peaked and faded, postmortems are underway. The CDC and World Health Organization are dissecting their responses to a virus that in a matter of days leap-frogged via jumbo jet from Mexico to the rest of North America, Europe and beyond.
As this story reveals, viruses don't follow a game plan, says Richard Besser, acting CDC director when the virus struck and now a medical correspondent with ABC News. "A plan is perfect until the virus strikes. Then you modify and adapt," he says, despite grave uncertainties. No one knows at the start how deadly a new virus will be, whether it can be contained, how quickly it will spread or who will be most severely affected.
Yet, despite their planning, swine flu took health officials by surprise. "The pandemic we were planning for isn't the one that happened," says Stephen Redd, CDC's flu-preparedness chief who ran the H1N1 flu response from the CDC's headquarters Operations Center. Global health officials had spent the past three years planning for H5N1 avian flu, one of the deadliest influenza viruses known.