That’s what the CDC is saying. In fact, the updated figures are triple the estimates the CDC issued just last week.

According to the new numbers, about 4,000 Americans, including 540 children, have died of H1N1 flu, and 22 million people have been infected since April, when the novel flu virus first surfaced. Contrary to initial impressions, health officials insist the increase does not mean that the disease has suddenly become more deadly or severe.

Until now, the CDC's weekly updates on the number of new cases, hospitalizations and deaths from the disease have included only laboratory-confirmed cases of H1N1. Many patients who come down with flu never go to a hospital or see a doctor and never get an official diagnosis. Many other flu patients who are admitted to the hospital may not be tested for H1N1 and may be treated under a different diagnosis. They may die from a complication, such as pneumonia, which is not reported as a case of influenza.

What can you do? Get with this DoSomething.org project: Influenza Pandemic Preparedness Postcards to inform your community about simple ways to protect themselves from a possible pandemic.