results of the field tests of the swine flu vaccine—the attempts to see if volunteers who were given the vaccine developed antibodies that would protect them against the swine flu. The vaccine worked well in people over age twenty-four—those who received it developed abundant antibodies against the swine flu. But children were not well protected, which meant that much more vaccine would have to be produced and that children would have to be induced to return for a second vaccine shot, complicating efforts to immunize the population.
