"The (H1N1) flu vaccine is made as flu vaccine is made each year. By the same companies. In the same production facilities. With the same procedures. With the same safety, safeguards," Dr. Thomas Frieden told reporters during a telephone briefing.
"We have had literally hundreds of millions of people vaccinated against flu with flu vaccine made in this way. That enables us to have a high degree of confidence in the safety of the vaccine. It has an excellent safety record," he said.
Frieden said the CDC "wished we had the vaccine earlier" but current science doesn't allow for production of the vaccine in much less than six months
"It would have been great to have had it back in April or May," he said.
He acknowledged that people have concerns about vaccinations and said that was "understandable" but he said the flu vaccine is "tried and true ... very effective."
Vaccine problems that could occur would likely occur at a very low rate -- 1 per 100,000, Frieden said.
"It would take some time to know there was a problem," he said. "On the other hand, there's no reason to think there would be more problem with this vaccine than with the vaccine each year."