HOUSTON, Sept. 18 (Xinhua) -- The first batch of A/H1N1 flu vaccinations will come in the form of a nasal spray, officials from the U.S. Centers for Disease Control and Prevention (CDC) announced Friday.

    Some 3.4 million doses of nose spray called Flu Mist would be distributed in the first week of October, Dr. Jay Butler, chief of the CDC' s A/H1N1 flu vaccine task force, said at a press conference Friday.

    "Initially we anticipate that 3.4 million doses of vaccine wil lbe available," Butler added.

    Butler estimated that the amount of available vaccine would increase through October, eventually rising to about 20 million doses a week.

    He didn't recommend Flu Mist for those in danger of serious complications from the A/H1N1 virus. This group includes pregnant women, children younger than 2, and people with asthma and other chronic respiratory diseases.

    The nasal spray vaccine was approved only for healthy people aged 2 to 49, Dr. Butler said, assuring that the spray and shot were equally effective for this group.

    He believed it was possible that some vaccine shots would become available by the first week of October as well.

    According to experts, the flu shots were made of killed influenza virus, while Flu Mist was a live but weakened strain. The nasal spray, only approved in the United States, is produced by the Maryland-based MedImmune, an AstraZeneca PLC subsidiary. Meanwhile, four other companies are making flu shots for the United States.

    The CDC said the U.S. government had ordered 195 million doses of A/H1N1 flu vaccine from the above-mentioned five companies.

    The A/H1N1 virus infection was first identified in the United States in late April. By August, 555 people had died of the new virus, and 8,842 had been hospitalized. More than 40,000 confirmed or probable cases had been reported, while more than one million infections were estimated to have occurred in the country.

Special Report:  World Tackles A/H1N1 Flu