Once a vaccine becomes available, Superintendent Arlene Ackerman said, any family with a child in the district will be able to get a dose.
Meanwhile, parents should pack pupils with alcohol-based hand-sanitizers and keep children at home if they get sick, Gallard said.
"This is the flu," Gallard said. "We want [people] to treat it as seriously as the flu. We don't want [people] to be cavalier about it."
If a pupil falls ill, he said, parents should "pick up your kids when the district calls."
When school starts, teachers and school nurses will demonstrate proper hand-washing technique and how to cough and sneeze without spreading germs, said Tracy Williams, the district's assistant director for school health services.
Ackerman said that each classroom would be supplied with hand-sanitizing dispensers.
"We're educating schools and the community," she said. "We want teachers especially to monitor kids closely."
Teachers themselves are not immune to the threat of infection, said Philadelphia Federation of Teachers spokeswoman Barbara Goodman. New teachers are more susceptible to getting sick than those who have taught in schools longer, she said.
"It takes a few years for the new teachers to build the antibodies they would need to survive the kids sneezing all over the classroom," Goodman said of the nearly 1,000 new teachers hired to instruct elementary-, middle- and high-school pupils this year.
Other vulnerable groups include pregnant women, children under 5 years old and people with underlying medical conditions, according to the federal Centers for Disease Control and Prevention.
In Pennsylvania, where 10 people have succumbed to the virus, 60 percent of more than 2,000 confirmed cases have been in people from 6 months to 19 years old, state Health Secretary Everette James said.
Most of the district's pupils are in that broad age range, Gallard said.
"We're keeping an eye on everyone, including adults," Gallard said, noting that school dismissals will be based on the city's recommendations and that no school will close unless a large number of teachers becomes ill.
Since April, swine flu - or the H1N1 virus - has killed about 500 people in the United States and has sickened nearly 2 million more, according to the CDC.
Unlike the seasonal flu, which typically weakens during the summer months, swine flu - which actually does not pose a greater threat than the seasonal flu - doesn't slow for most of the season.
Philadelphia, which has the largest municipal health system in the state, most likely will vaccinate through private providers and health clinics, not through schools, James said.
An agency can register online to be considered for a vaccination site.
Although some critics dismiss virus concerns, officials urge people to take the swine-flu vaccination as well as the seasonal-flu shot.
Other guidelines include: * Practice coughing and sneezing etiquette;
* Stay home for 24 hours after fever has lifted without the use of drugs;
* Disinfect commonly used surfaces;
* Isolate sick people from the general population.