An influenza virus vaccine vial sits on the counter of medical center in Great Neck, New York, October 22, 2004. REUTERS/Shannon Stapleton SS  But they said school closings would create significant  hardships for working parents, who might be forced to create  informal daycare arrangements that would undo efforts to  contain the spread of flu. “We find school closings would be less effective than some  studies have suggested,” said Dr. Simon Cauchemez of Imperial  College London, whose study appears in the journal Nature. “The main effect would be to slow and flatten the outbreak  — so the numbers becoming ill in the worst week of the  outbreak might be reduced by up to 40 percent, reducing peak  demand on health-care systems,” Cauchemez said in an e-mail. Health experts almost universally agree that a global  epidemic — a pandemic — of influenza is overdue. The most  likely cause now is H5N1 avian influenza, which could evolve  into a form that passes easily from person to person. Government estimates suggest vaccines and drugs will not be  enough to slow or prevent a flu pandemic. The U.S. pandemic  plan recommends closing schools and implementing strategies to  limit social contact as a way to limit transmission. If done quickly, such widespread measures combined with  drugs and vaccines might reduce transmission in a large city by  as much as 80 percent, by one estimate. But such estimates are often based on widely varying  assumptions, Cauchemez said. He and colleagues instead used  public health data from France that compared flu transmission  when school was in session and during school holidays. They found school holidays prevent 16 to 18 percent of  seasonal influenza cases. When extrapolated to a pandemic, they  said prolonged school closure might reduce the cumulative  number of cases by 13 to 17 percent, and peak attack rates by  39 to 45 percent. But that impact would be reduced if it proved too difficult  to keep children apart. “If we want the policy to have an  impact, children must be kept relatively isolated and not cared  for in groups,” Cauchemez said. U.S. cities that quickly closed schools and discouraged  public gatherings during the great flu pandemic of 1918 —  which killed tens of millions of people globally — had as many  as 50 percent fewer deaths than cities that took less decisive  measures, according to a recent study. Cauchemez said an especially deadly pandemic might provide  strong incentives for people to keep their children at home. “It might nonetheless be difficult for a lot of working parents  to be absent from their work for months to look after their  kids,” he said. Cauchemez said a prolonged outbreak might force working  parents to put their children into informal daycare settings, a  risk governments need to consider when they formulate pandemic  flu plans. “We can’t predict how people will behave, but we need to be  aware that if this happens, school closings might have no  effect at all on flu transmission,” he said. H5N1 bird flu only rarely infects people now. It has killed  239 out of 379 infected, according to the World Health  Organization, but could easily mutate into a form that one  person could pass to another, and governments around the world  are preparing for the possibility.
School closings may be no holiday for flu pandemic.