DENVER -- The H1N1 vaccine is expected to arrive later in the year, as early as mid-October, but the infection count has jumped dramatically this week with dozens of new cases confirmed in southern and northern Colorado.

Exact criteria for who should get the vaccine are still being worked out but the likely populations include school-age kids, preschool and child care attendees, adults under age 65 with chronic medical conditions, pregnant women and health-care workers.

Dr. Ned Calonge, chief medical officer at the Department of Public Health and Environment, said. "It's going to be important for residents to pay attention to public health messages this fall and winter, because there will be a lot of information about the two types of flu vaccines that are expected to be available. The information will assist residents with the plans they need to make for getting the vaccinations they need, and staying safe at home, school and work."

The H1N1 vaccine will also be free to the public, said Mark Salley, communications director for the state health department.

The news follows a week of serious increases in the number of people, especially young people, infected with the respiratory illness.

At the Air Force Academy in Colorado Springs, another 30 freshmen have tested positive for H1N1, bringing the total number of infected cadets to 97.

At the University of Northern Colorado in Greeley, five younger students attending a summer enrichment program for fifth- through 12th-graders now have swine flu.

A Boy Scout camp in Buena Vista was closed last month after a handful of confirmed H1N1 cases.

Calonge said parents shouldn't necessarily rule out the summer camp ritual due to fear about the illness.

"If you know H1N1 is not circulating in your camp and your child isn't suffering from a chronic illness, you should not worry about sending your child to camp. This is a time to plan and be prepared, and there are steps you can take to protect yourselves against the flu," Calonge said.

Colorado has already received $1.4 million from the U.S. Department of Health and Human Services to prepare for a possible influenza pandemic this fall.

Calonge said another $4 million from a Public Health Emergency Response grant from HHS will help support several efforts including:

strengthening and sustaining the public health work force

increasing laboratory capacity and capability

strengthening disease surveillance activities

planning and implementing possible large-scale mass vaccination activities

developing and communicating effective public guidance to lessen the impact of the illness in communities

purchasing and procuring personal protective equipment, antivirals and other pandemic-related purchases for protecting the public health work force

training and educating of the public health work force

community and personal preparedness activities

addressing gaps and other public health preparedness challenges related to public health preparedness and response to an influenza pandemic.

The World Health Organization has been sounding the alarm about H1N1 for months, and Thursday changed the way it tracks the global swine flu outbreak, deciding to no longer publish the confirmed cases in all countries.

While acknowledging that the majority of the confirmed H1N1 cases have produced mild symptoms with patients usually recovering within a week, even without medical treatment.

The WHO says, "This influenza pandemic has spread internationally with unprecedented speed. In past pandemics, influenza viruses have needed more than six months to spread as widely as the new H1N1 virus has spread in less than six weeks," according to a statement posted Thursday at www.who.int