As reported by The Hartford Courant, May 3, 2009.

Remembering the Lessons of 1918's Spanish Flu Outbreak

By Arielle Levin Becker

It started in New London, then crept across Connecticut, killing men and women in Hartford, Middletown, Norwich, Waterbury and more than two dozen other towns as September wore on. Then, in October, it took off, killing 5,228 people throughout the state in one month alone.

The Spanish flu of 1918 moved across the world slowly compared with the current spread of swine flu known as H1N1. But the 1918 flu proved to be deadly, killing nearly 9,000 people in Connecticut, 650,000 in the United States and between 20 million and 40 million worldwide.

It's too soon to know the course of the current outbreak of swine flu, whether it will mirror any of the three pandemics of the 20th century or die off far short of any kind of comparable destruction.

So far, the swine flu has been linked to only one U.S. death and 725 confirmed illnesses worldwide. Most cases are in Mexico, where 19 deaths have been reported.

Most of the U.S. cases have been mild, and it's possible that the swine flu's impact will more closely resemble that of a typical seasonal flu — the kind that kills approximately 36,000 Americans a year but leaves most people who have it unscathed — than a pandemic of any kind.

But as scientists and public health officials work to get a handle on the swine flu, the history of past flu pandemics looms in the public consciousness, informing public health efforts, bringing into relief the vastly different world that swine flu strikes and raising a host of questions.

Does the relatively mild nature of the current strain mean a mild outbreak, or could it mutate into something far more deadly, coming back in intensifying waves like the 1918 flu did?

Or could it peter out, much like the feared swine flu of 1976 that prompted a massive government response?

And, even if a strain like the 1918 virus came along, would all the changes since then — antiviral treatments, global communications, the ability to track a disease in its earliest stages — protect us from such massive mortality?

History offers some clues, including this one: The influenza virus can defy our best guesses.

"It's very, very unpredictable," said Dr. Richard Garibaldi, hospital epidemiologist at the UConn Health Center. "I think that's a historical fact that humbles us all."

Different World
This flu comes in a different context from the Spanish flu of 1918, the Asian flu of 1957 or even the Hong Kong flu of 1968.

For one thing, there's the prevalence of global travel, a fast way for infectious diseases to spread. Swine flu didn't take months to spread worldwide; it moved across the globe rapidly, appearing in Mexico in late March and making its way to Israel, Canada, New Zealand and other nations by the end of April.

If the Spanish flu traveled in waves, swine flu's course has been more like an explosion, Garibaldi said. It's instructive, he said, for understanding what could happen if a more virulent strain were to spread.

The 1918 flu outbreak came near the end of World War I and, in less than a year, killed more people than died in the war. In Connecticut, 8,907 people died of influenza, and 2,336 more died of pneumonia.

The outbreak hit in waves, changing in severity as it spread from continent to continent, a process that took months. A full 30 percent of the population became ill, and 2 percent of those died. Those aged 20 to 40 experienced especially high mortality — much like the swine flu deaths initially reported in Mexico.

Ninety-one years later, public health officials make preparedness plans around projections of such severe pandemics.

In a presentation to lawmakers, epidemiologist Dr. Matthew Cartter of the state Department of Public Health projected that a flu pandemic on the scale of 1918 could lead to 102,348 hospitalizations in Connecticut and 23,852 deaths.

Even a less severe outbreak like the one that occurred in 1968 — the most recent flu pandemic — could mean 12,451 people in the hospital and 2,902 dead in Connecticut.

"We have devised a tremendously effective means of moving viruses very quickly from one country to another," said Dr. Sandro Galea, director of the Center for Global Health at the University of Michigan. In particular, he cited "the silver tubes that we fill with bugs and send from one country to another on a regular basis."

He was talking, of course, about airplanes.

But along with swift travel, we now have nearly instant means of communicating, allowing both experts and regular people to report and track the earliest cases of an outbreak in all corners of the world. By early last week, possible swine flu cases were being tracked on Google Maps.

We have other advantages, too — antiviral treatments that appear to work on swine flu. Scientists are better able to identify the virus and tailor vaccines. We understand better how diseases are spread and have products that help stop them, like antibacterial hand gels. Medical capabilities have improved dramatically.

The rapid detection, real-time information and coordinated management among countries could insulate us from the kind of destruction that the 1918 flu wreaked, Galea said.

"There's always little we can do about a pandemic that results from a random mutation in a virus that is going to be very pathogenic," he said. "The question is have we gotten better in dealing with it, and I think we have."

Defies Predictions
But it's still the same basic disease — a virus that can mutate and defy predictions. One of the least predictable aspects of flu is whether it will mutate into more pathogenic strains that could be more dangerous.

That is one of the reasons why, even though the earliest swine flu cases in the U.S. appear relatively mild and lack the genes that made the 1918 strain so deadly, public health officials are monitoring them closely.

"There's now growing evidence that this appears to be an influenza strain that causes infections in humans that are probably no worse than our seasonal influenza. It can be bad but not worse than that," Garibaldi said. "But we're still reserving the right to change that judgment as new cases get identified."

Perhaps swine flu will end up like a seasonal flu, a deadly illness that rarely makes headlines.

Perhaps the swift public health response — precautionary school closings, repeated lessons on the importance of hand-washing, cough-covering and staying at home while sick — will stem the outbreak before it sickens enough people to rank with the flus of 1918, 1957 or 1968.

Cartter likens the current situation to watching the weather: If a pandemic is a hurricane, we're now watching a tropical storm in the Caribbean, waiting to see what it will become. In the meantime, government officials and hospitals are preparing for the worst.

William Johnston, a Wesleyan University professor who studies the history of disease, used another weather metaphor for the flurry of activity surrounding swine flu.

Forecasters might predict an 80 percent chance of severe snowstorms, prompting schools to close and everyone to take precautions. Then the snow comes, but not nearly as bad a storm as predicted, leading people to question why it led to such a frenzy.

"A lot of this is a precaution, but it's smart," Johnston said. "It does have the potential to go bad."