About 25 million people, or some 20 percent of the population, are expected to become infected with swine flu, the Health, Labor and Welfare Ministry said Aug. 28.

Some 380,000 people, or 1.5 percent of the anticipated cases, are expected to be hospitalized and 40,000, or 0.15 percent, are expected to develop serious symptoms like encephalopathy or need to be aided by respirators, according to the ministry's estimates.

Meanwhile, the National Institute of Infectious Diseases said in a report Aug. 28 that about 150,000 people probably caught some form of the new H1N1 strain of influenza in the week that ended Aug. 30.

The health ministry anticipates that the epidemic will peak around late September to early October.