If residents do not get vaccinated against seasonal strains and later get sickened by them as a result, there will be little way to determine if those falling ill this fall and winter have been infected by less worrisome strains, or by the more contagious H1N1 virus, O'Malley said.

The governor characterized that scenario as serious because it could stress supplies of antiviral treatments and other resources needed to care for swine flu victims, since only those Marylanders sick enough to be hospitalized may undergo tests to confirm the presence of swine flu, state health officials said.

"You'll be doing your patriotic duty to get your seasonal flu shot this year," O'Malley said. If you've never received one, "by golly, this is a very good year to do it for the first time," he said.

O'Malley's plea for state residents to voluntarily get seasonal flu shots in advance of a larger effort this fall to vaccinate children, pregnant women, health-care workers and others against swine flu followed a closed-door meeting with his cabinet and leaders from state public-safety and health-care agencies. The meeting came one day after those and other agencies were required to submit contingency plans for how to keep the state government working should thousands of transportation workers, state police, hospital employees or others fall ill with H1N1.


Maryland, home to the nation's swine flu summit in July at the National Institutes of Health, was notably aggressive compared to Virginia and other states during the initial H1N1 scare this spring in terms of releasing information to the public about possible and confirmed swine-flu cases. The state has since enhanced its own contingency plans for dealing with the virus, adding to, for example, its web of backup operations centers, should sickened employees force officials to close key offices.

John M. Colmers, secretary of Health & Mental Hygiene, likened Maryland's share of the upcoming mass swine-flu vaccination campaign to a "military operation," and said much remains unknown about exactly how the state will carry it out. Unlike seasonal flu shots, which are available now, swine flu vaccines will not be ready until at least mid-October, and even then only in limited quantities.

"We're trying to match what we know about the supply of the vaccine and its particular formulation with the target populations and when we believe it will arrive," Colmers said. He stressed that the only thing the state knows for sure is that it won't initially have enough doses to vaccinate the roughly 2.9 million state residents considered most at risk.

Colmers said the state is waiting for precise directions from the Centers for Disease Control as to whether pregnant women, school-age children, toddlers or others will be first in line for vaccinations.

Greg Reed, head of the Maryland Center for Immunization, said that once that decision is made, Maryland will have direct authority to instruct McKesson, the nation's sole distributor for the vaccine, to send shipments to the appropriate doctors' offices or other immunization centers.

"If it's pregnant women, we'll send those initial doses directly to OB/GYN and others who specialize in their care. If it's children less than 4 years old, we'll send them straight to pediatricians' offices," Reed said.

Whichever group goes first, the effort will be far different from the annual flu shot campaign, which typically targets seniors.

Roughly 30 percent of residents in Maryland opt for seasonal flu shots each year, health officials say, and there's little overlap with that population and the one that will be asked to vaccinate against H1N1. Just 42 percent of Maryland health care workers, for example, now take flu shots.