"More than three million doses of swine flu vaccine will be available by the first week of October, a little earlier than had been anticipated, federal health officials announced Friday," McNeil wrote.
This lead quickly reports most of the main who, what, when, where, why, and how questions. The who answer provided directs readers' attention to health officials. The what answer involves the availability of the recently-found swine flu vaccination. The inclusion of "Friday" describes when the announcement was made.
This lead does not include where the vaccination will be available, and how or why it is available. The lead remains vague on when and where the vaccinations will be available because this information may not yet be set.
Readers are expected to understand why information about a vaccination for the swine flu is important because it is a dominant topic in the media. Readers are not expected to understand how health officials found the vaccination because it is a complex scientific process.
McNeil does specify the amount of doses available because this information is important for the American public. Three million doses are available. However, the United States has a population of 304 million.