ATLANTA (AP) -- Health officials think that as many as 5.7 million Americans were infected with swine flu during the first few months of the pandemic.

Scientists at the Centers for Disease Control and Prevention estimate that between 1.8 million and 5.7 million Americans were infected from April through July. The estimate is the CDC's most specific calculation to date. Officials had simply been saying millions have been infected.

The estimate is in an article in a CDC publication called Emerging Infectious Diseases.

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