Chiron Vaccine Doses Tainted

The United States’ supply of vaccine for the impending flu season took a hit Thursday when Chiron Corp. said it had found tainted doses in its factory.

Chiron said it would delay shipment of nearly 50 million shots -- about half the supply health officials had hoped to have on hand this year.

Chief Executive Howard Pien said the company hoped to ship 46 million to 48 million doses by early October, about a month later than usual, pending the results of an internal investigation. About 1 million doses have already been shipped, but no vaccines have yet reached the public, Pien said. Vaccinations usually begin in September and continue through the flu season.

Pien said a small number of batches had been contaminated at a company factory in Britain, and that the problem didn’t appear to be widespread.

The Emeryville, Calif.-based company’s announcement of the problem was made after the close of regular trading, during which shares of Chiron slipped 52 cents to $47.49 on Nasdaq. Chiron fell to $44.36 during after-hours trading.