By David Brown
Washington Post Staff Writer
Wednesday, December 13, 2006
New analysis of how American cities responded to the killer Spanish flu of 1918 suggests that closing schools, banning large gatherings, staggering work hours and quarantining households of the ill may have saved tens of thousands of lives.
Which of the many non-pharmaceutical interventions was especially effective in reducing mortality is unknown, but all would theoretically be available should pandemic influenza again sweep the country.
The new findings run counter to previous research that concluded that the public health measures instituted in 1918 may have delayed or dampened the epidemic in many cities but probably had little effect on the ultimate death toll.
The new data were presented this week to Centers for Disease Control and Prevention experts, who are helping to draw up guidelines for what local health departments might do during the early stage of an influenza pandemic, when a vaccine would be unavailable and there would be too few antiviral drugs to go around.
"There is reason for optimism. Even almost 100 years ago, with some very simple tools, there may have been an effect of these measures," said Martin Cetron, a physician who directs global migration and quarantine at the CDC.
Many epidemiologists think the time is ripe for an influenza pandemic: the outbreak of a novel, contagious strain of the virus capable of infecting virtually everyone on Earth.
The H5N1 strain of avian influenza, which since 2003 has killed millions of birds and 154 people, mostly in Asia, is considered by many experts to have pandemic potential. The latest victim was a 35-year-old Indonesian woman who died Nov. 28 -- the 57th fatal case out of 74 in that country.
In 1918, the public health responses included isolating the ill, quarantining houses, closing schools, canceling worship services, restricting the size of funerals and weddings, closing saloons and theaters, restricting door-to-door sales, discouraging the use of public transportation, staggering the hours of business and factory operations, imposing curfews and, in some places, recommending the use of face masks in public.
Howard Markel, a physician and historian at the University of Michigan Medical School, is leading a project to analyze the experience of 45 American cities, looking for relationships among flu cases, mortality and public health measures.
The researchers used a model to determine what the epidemic would have looked like had no measures been taken and compared that result with a city's actual experience.
St. Louis closed its schools at a time when flu was causing 21 more deaths per 100,000 people per week than what had been seen in previous years. That step -- the earliest taken by any of 33 cities analyzed so far -- appears to have reduced St. Louis's flu mortality by 70 percent.
Cincinnati responded less quickly, invoking public health measures when excess deaths from flu were 46 per 100,000. It reduced its potential flu mortality by 45 percent. Philadelphia was extremely late, not acting until its excess death rate was 250 per 100,000. That reduced mortality by 28 percent, Markel and his colleagues found.
How U.S. communities would react to a sudden closure of schools is uncertain, although the experience this past fall of one rural Appalachian county suggests that there may be little opposition over the short term.
Yancey County, in rural and mountainous western North Carolina, closed its 2,559-student school system from Nov. 2 to 13 because of an outbreak of influenza B. A random survey of households found that 91 percent supported the school board's decision.
In half of those households, all the adults worked outside the home. During that period, one-quarter of them had to take time off from work, mainly because they were ill themselves or had to care for a sick family member, and not simply to stay with children not in school, said April J. Johnson of the CDC's Epidemic Intelligence Service, who investigated the outbreak.
In only two of 220 households did adults have to pay for extra child care when schools were closed. In most cases, relatives and friends stepped in to help, Johnson found.