School-age children will be a key target population for a pandemic flu vaccine in the fall, and they may be vaccinated at school in a mass campaign not seen since the polio epidemics of the 1950s. The federal government should get about 100 million doses of vaccine by mid-October, if the current production by five companies goes as planned. But enough vaccine for wide use by the 120 million people especially vulnerable to the newly emerged strain of H1N1 influenza virus will not be available until later in the fall. Those were among the messages administration officials delivered to about 500 state, territorial, city and tribal health officials yesterday at a flu summit" at the National Institutes of Health's Bethesda campus. President Obama, speaking by audio link from the Group of Eight summit in L'Aquila, Italy, urged "complete ownership" of preparations for what he termed a "significant outbreak" of H1N1 flu in the next few months. "We want to make sure that we are not promoting panic, but we are promoting vigilance and preparation," he said. He added that "the most important thing for us to do is to make sure that state and local officials prepare now to implement a vaccination program in the fall." Children, pregnant women, adults with chronic illnesses, and health-care workers would probably be first in line for the vaccine, Health and Human Services Secretary Kathleen Sebelius told the gathering. Education Secretary Arne Duncan said "we would absolutely welcome" the idea that the nation's schools be a principal venue for delivering the vaccine. He called them "natural sites" and said that "to open our doors and be part of the solution really makes sense."