Millions of H1N1 Doses Will Expire on Feb. 15

Approximately 70 million people have been vaccinated against the H1N1 virus, Schuchat said, which translates to about 23.4% of Americans.

Schuchat said that H1N1 flu cases have been below the national baseline for the past three consecutive weeks. "That's fairly similar to what we would normally see at this time of year with seasonal flu," she said. However, pneumonia and influenza deaths as a proportion of total deaths have actually been above "the epidemic threshold level" for three consecutive weeks.

"Nearly all the flu viruses that we're seeing right now are the H1N1 pandemic strain. We're not seeing seasonal flu strains yet in any substantial numbers," she said. "We are remaining vigilant here and do not think people should become complacent. As I said, individual cases of the H1N1 influenza continue to occur, and people are being hospitalized. They're dying."