The chief of the Centers for Disease Control and Prevention is just as frustrated as everyone else in America with the shortage of H1N1 vaccine.

Dr. Thomas Frieden said Friday that the old "chicken-and-egg" technology being used to manufacture the new vaccine just doesn't cut it in the 21st century.

"As public officials, vaccination is our strongest tool," Frieden said. "It’s frustrating for all of us. But it’s important to remember the enemy here is the virus. It’s challenging to deal with, and the tools we have to deal with are not as modern as we’d like."

Those challenges include millions of people infected with the virus, 46 states reporting widespread flu activity, and the numbers still increasing. As of Friday, 95 children in American have died from H1N1 influenza.

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"Since the beginning of the pandemic, we’ve seen more than 1,000 deaths and 20,000 hospitalizations," Frieden said. "We expect it to occur in waves, but we can’t predict when those waves will happen."

Only four states — Connecticut, New Jersey, South Carolina and Hawaii — are not reporting widespread flu activity.

The good news, Frieden said, is that the virus has not become more severe since the spring, and it has not evolved into a more serious strain.

Because FluMist is being produced at greater speed and is more readily available than the H1N1 injection vaccine, Frieden said healthy children and adults between the ages of 2 and 49 should take advantage of the nasal spray.

But pregnant women — who are six times more likely to die from H1N1 — cannot get the nasal spray form of the vaccine, since it is a live, albeit weakend, virus.

Polls show a large number of people are concerned that the vaccine may not be safe, because it was manufactured to prevent infection from a new virus.

"I can understand the reluctance of taking a vaccine that appears to be new and different," Frieden said. "But it's the same manufacturing process, the same factories, the same safeguard as the seasonal influenza vaccine, which has an excellent track record.

"If the pandemic occurred earlier, the H1N1 vaccine would've been rolled into the (seasonal) flu shot."

Frieden said the CDC thinks the vaccine shortage will eventually end, but he could not offer an exact date of when that would happen.