U.S. health officials are cautiously optimistic that the new swine flu isn't as dangerous as first feared, but urged people to keep taking commonsense precautions — and they can't predict if it will roar back in the fall.
"We're not out of the woods yet," said Dr. Richard Besser, acting chief of the Centers for Disease Control and Prevention.
With swine flu, or the H1N1 flu as the government prefers to call it, now in 21 states and counting, authorities say it's spreading just as easily as regular winter flu, but fortunately doesn't seem to cause as severe disease as it did in Mexico, where there are signs the outbreak is waning.
But the CDC says its own count is outdated almost as soon as it's announced. More cases are being confirmed daily. About one-third so far are people who had been to Mexico and probably picked up the infection there. Many newly infected people are getting the illness in the U.S., and the CDC says it probably still is spreading.