The Centers for Disease Control and Prevention says the United States will roll out its first swine flu vaccines, 3.4 million doses of Medlmmune's nose spray, in about three weeks.
The CDC in Atlanta says it expects to start receiving orders for the vaccine the first week of October.
The United States has ordered 195 million doses of the vaccine from five companies: MedImmune, a unit of AstraZeneca, Sanofi-Aventis, CSL in Australia, GlaxoSmithKline and Novartis.
It has recommended that about 160 million people, roughly half the population, get vaccinated first: pregnant women, healthcare workers, children and people with chronic conditions such as diabetes or asthma, who are most at risk of getting very ill from flu.
The vaccine is expected to be provided free to about 90,000 distributors, including doctor's offices, retail chains and state health departments.