Though the Department of Health and Human Services is warning that swine flu vaccines may not take full effect until Thanksgiving, city officials say they don't think the flu will shutter schools.

HHS Secretary Kathleen Sebelius told CNN on Sunday that the vaccine will take about five weeks to reach full protective strength after it's administered, which means parents need back-up plans if they or their kids get sick in the meantime: "We're preparing for the worst and hoping for the best." Sebelius adds that the vaccine is still on schedule to arrive in October, but immunization will not be a one-shot deal: "The regimen will take about five weeks...A first shot, three weeks delay, second shot, and then about two weeks for full immunity."

Even with the vaccine's lengthy ramp-up time to protection, the Daily News reports that city Health Department officials are still planning to keep schools open this fall: "Schools will be less likely to close as a precaution, because it tended to have little impact on a virus that had almost no serious effect on those it infected." The city also plans to drop the daily public tallies of H1N1 patients, since that is a poor indicator of the flu's spread. Dropping the tally may also have a calming effect on public fear, for as deputy emergency management commissioner Kelly McKinney notes, "Eight or nine out of every 10 people who showed up in ERs during the spring weren't really sick."