Federal officials plan to double the stockpile of emergency bird flu vaccines as they identify more people infected with the disease. Three manufacturers were awarded $72 million to increase pandemic preparedness including against avian influenza, officials announced in a Friday morning briefing.

Antibody blood test results expected later this month may help answer a crucial question: Is there human-to-human transmission of the bird flu?

Both patients were dairy workers whose illnesses were mild. Investigators are continuing to evaluate the contacts of a Missouri patient who had no exposure to animals.