Swine flu vaccine taking longer than expected, WHO says

The World Health Organization said Tuesday that it was taking longer than anticipated to prepare the seed stock needed to manufacture a vaccine for the H1N1 influenza virus.

At a weeklong meeting in Geneva to discuss the outbreak of the so-called swine flu, the global health agency said the virus wasn’t growing very quickly in the laboratory. That means vaccine makers won’t be able to start production until mid-July at the earliest.

WHO officials originally said they would be able to deliver the seed stock to manufacturers by the end of the month. Once the companies have it in hand, it takes about four to six months to produce the vaccine.

The U.S. Centers for Disease Control and Prevention in Atlanta intends to have its own H1N1 seed stock ready to distribute to vaccine makers by the end of May, and those efforts are “still on track,” spokesman Tom Skinner said Tuesday. Small lots of H1N1 vaccine could be available for human clinical trials as early as late July or August, he said.

Neither the WHO nor the CDC has given the go-ahead for manufacturers to begin production of an H1N1 vaccine.