The technology used to develop this vaccine grows the virus in chicken eggs, which is why people who have allergies to eggs cannot take vaccines produced this way.

Although this is the oldest technology, and therefore well understood, it also is subject to all the variables involved when you are counting on the chickens to help.

More vaccine is on the way, however. Federal officials say that they expect much more to be shipped soon but do not commit to a number.

The Wall Street Journal

“Less than half of the swine-flu vaccine expected to be shipped to doctors, hospitals and clinics in the U.S. this month has been shipped so far. The disease now is widespread in 46 states and the U.S. death toll has passed 1,000.

“The delays are occurring around the globe, officials said, and are due to a series of manufacturing difficulties, as vaccine makers scramble to fill vast orders using an old technology that requires growing virus in chicken eggs. (Emphasis added)

“It takes about six to nine months to produce vaccine once a flu strain has been identified. (Emphasis added)

“A total of 11.3 million doses of vaccine had been shipped to U.S. doctors, hospitals, and clinics as of Wednesday, according to the federal Centers for Disease Control and Prevention, out of a total of 14.1 million doses that manufacturers had shipped to warehouses by that time.”

Source: Wall Street Journal, October 24, 2009