The conference room at the Fairfax County Department of Health opened for business at 8:30 a.m., and Diane McDaniel was an early customer. She wore a look of happy anticipation as she walked up to the table with the "Pay Here" sign taped to it. In one hand she held the small, green-topped container she normally loads with sodas for trips. In the other hand was a check for $2,998.80.

Department officials in the makeshift distribution center took the check. McDaniel signed for her office. Into her cooler went 36 tiny vials of a precious liquid -- enough for 360 flu shots.

Within a half-hour, the first of those shots was in the left arm of 68-year-old Marjorie Einhorn, a longtime asthma sufferer who had almost lost hope of finding any vaccine. "I've been calling around a lot of places," she'd told nurse Peggy Espejo as she rolled up her sleeve at Northern Virginia Pulmonary and Critical Care Associates. "The grocery store, CVS, the county. I called four doctors, and you're the only one who responded."

The convoluted path Einhorn's flu shot took before finally reaching her last week illuminates the complex system that government authorities at all levels have struggled to construct since the nation lost half its expected inventory for this influenza season.

There was no precedent to follow, no formula they could plug in and ascertain how to allocate the 24 million doses that had not been shipped when the crisis began in early October. There was no quick, sure way of knowing exactly where the vaccine was that already had been sent into the private sector, minus what had been used.

The situation remains confusing and frustrating for countless Americans still searching for a dose of their own. Yet under strict control of the federal Centers for Disease Control and Prevention, vaccine has begun to flow to those in identified, high-risk groups.

It's just that the pipeline operates in vastly disparate ways once it reaches a particular state, county or city.

Maryland has largely defined its role as that of a vaccine broker, as Greg Reed explained. As program manager at the state immunization center, his first goals have been ensuring local public health agencies at least 100 percent of their pre-shortage orders and determining gaps in availability, based not just on counties' and cities' health demographics but on shipping data from Aventis Pasteur, the country's sole supplier this year.

Reed and other state officials have focused little on moving vaccine to the private providers who administer the vast majority of shots.

Their approach explains several seeming incongruities. Why, for example, they have directed 2,850 doses so far to Prince George's County, more than double the number that jurisdiction's health department expected initially. And why Montgomery County's department has only 800 doses via the CDC distribution, despite a Montgomery lottery for those at greatest risk that drew a stunning 20,000-plus applicants.

The District has tackled its task differently, dispensing its CDC allotment to date in part through the two local medical societies. About 3,000 of 15,610 doses will go to physicians or medical practices that responded to those organizations' e-mail inquiries. An equal number is targeted by the city's Office on Aging for seniors in its programs.

Virginia settled on a different calculation. It divided proportionally the more than 77,000 doses sent in late October among its 35 health districts. All but a few of those districts order vaccine annually through the state pharmacy, and because this year's centralized order was to be filled by the company whose U.S. product was rejected as possibly tainted, there was virtually no public vaccine in Virginia.

Doing that math hardly simplified matters. Virginia Health Commissioner Robert B. Stroube required each jurisdiction to submit an allocation plan based on its most pressing needs. "There was essentially no wrong answer," he said. Some districts decided to include nursing homes. Some planned only by-appointment immunizations. Chesterfield County near Richmond held a drive-through clinic so no recipient would have to stand in line in bad weather -- though one unforeseen consequence was a three-mile traffic backup.

Fairfax County Health Director Gloria Addo-Ayensu convened an internal group to discuss how the department should proceed. Virginia's census-based formula meant nearly 11,000 doses for Fairfax. Addo-Ayensu, who'd been greatly disturbed last month by the huge crowds at grocery store immunization clinics, wanted to coordinate with the Medical Society of Northern Virginia.

"It was an obvious thing to me to get physicians in the county involved," she said. "They're the only ones who can help you avoid long lines." Beyond that, she said, only the physicians knew who really was neediest, based on health condition or advanced age. On Oct. 27, she had the society's executive director, president and two board members review two proposals. Also listening in was Alexandria Health Director Charles Konigsberg, who worked recently with his medical community to direct 1,600 newly arrived shots to 75 doctors.

During a protracted conference call, the participants agreed that Fairfax's agency would survey physicians by fax. About 6,500 doses would be divided among those wanting vaccine based on the quantity they had received previously, the numbers of high-risk patients who had and had not been vaccinated and the number of direct-care staff members ineligible for the FluMist nasal spray vaccine.

"Not a perfect science," Addo-Ayensu said, but a formula with a rational foundation.

But how to get shots to those patients?

The panel rejected the idea of the department's giving doctors a certain number of preprinted cards, which they in turn would give patients to redeem for shots at county health offices.

Instead, the doctors would retrieve and administer their own allocations. As for the remaining 4,345 doses, the department would take reservations by phone for three days of public flu-shot clinics.

The survey went out to 1,026 physicians Nov. 1. More than 330 responded, with 273 doctors in 100 practices requesting vaccine. Nearly three-quarters were family medicine or internal medicine practices, but a dozen other specialties asked to be included, from cardiology and infectious disease to rheumatology and obstetrics-gynecology.

By Nov. 3, the 10,845 doses had come in. Nov. 8, the health department notified the designated doctors. "Urgent -- Immediate Attention Needed," its letter was headlined.

"Our goal is to try to allay as much anxiety as possible in the community," Addo-Ayensu said last week. Past a certain point, "you can't do that with words. You need vaccine."

At Northern Virginia Pulmonary and Critical Care, obtaining at least a fraction of its planned supply has been a critical issue. All its patients fall into priority categories because of asthma, lung cancer, cystic fibrosis or other chronic respiratory problems. Two already have tested positive for influenza this fall. (One, a shopping mall Santa, came in with a 104-degree fever.)

"We've had patients say, 'You're lung doctors! How can you not have' " vaccine? said James Lamberti, one of the eight physicians there. "That's what's so hard. People do not understand it's catch as catch can."

Even with the several hundred doses office manager McDaniel brought back from Fairfax's health department and an out-of-the-blue offer of another 300 from a primary care office, Lamberti and his colleagues will be saying no more than yes. The boxed vials of Aventis Fluzone -- expiration stamped 30 Jun 05 -- will protect fewer than half their patients.

Most medical practices in the area are in the same position, or worse. Nurse Corazon Lao of Renal Care Partners of Reston got 20 doses at the distribution Monday, a paltry pair of vials she put in a container that could have held dozens. She left shaken, wondering who of 74 dialysis patients would benefit and who would be denied. "How will I choose which patients I give it to?" she asked.

As the pickups continued, Espejo was again on the phone in her Annandale office, checking off names on a handwritten, pages-long waiting list. Those on the other end of her calls were "just ecstatic," she said. "It's almost like they've won the lottery."

Ecstatic and yet, after all their searching, a little incredulous.

"Yes, we did . . . " Espejo told one person, repeating the news of the vaccine's arrival.

"And if you want to come in Wednesday afternoon. . ." A pause, then some bad news. "Unfortunately, we only can do our patients. We have a limited amount."

Another pause on Espejo's end.

"Between 1 and 4 o'clock?" Confirmed.

"Okay, we'll see you Wednesday."

Pharmacist Tom Moore removes vials of flu vaccine from coolers for Diane McDaniel, left. McDaniel, left, heads back to Northern Virginia Pulmonary and Critical Care Associates, where she is the office manager. At the facility, nurse Peggy Espejo, above, prepares a flu shot. Espejo, left, injects Marjorie Einhorn, a longtime asthma sufferer who said she had almost lost hope of finding flu vaccine. "I've been calling around a lot of places," Einhorn told the nurse. "The grocery store, CVS, the county. I called four doctors, and you're the only one who responded."Pharmacist Tom Moore helps office manager Diane McDaniel with her facility's allotment of 36 vials of flu vaccine, enough for 360 flu shots.