When the Food and Drug Administration deemed 48 million doses of Chiron Corporation's influenza vaccine unsafe because of bacterial contamination last year, America lost almost half its vaccine supply.

As flu season approaches, students, local residents and health care workers alike are wondering what the vaccine situation will be like this year.

In 2004, Duke University Medical Center was left with only 10 percent of its anticipated supply. The situation forced DUMC to order vaccines from other sources on short notice, and many people were still left unvaccinated.

"Not everyone who wanted a vaccine last year could get one because of the problems with Chiron, but we don't expect shortages this year," said Dr. John Engemann, associate in the Department of Infectious Diseases and International Health.

Frank Sloan, professor of health policy and management and economics, was more wary. He said issues could arise as the flu season approaches.

"When problems do come up, they're unexpected-that's why they're problems," Sloan said.

Chiron's withdrawal would not have affected the University as much if the orders had been distributed over more manufacturers, but DUMC had ordered 90 percent of its vaccines from Chiron. Similarly, almost 80 percent of this year's doses have been ordered from a single manufacturer, Sanofi-Pasteur. DUMC officials expect the doses to be delivered without complications, as they have already been shipped.

Flu vaccines have to be reformulated from year to year because the virus mutates. This discourages companies from joining the flu vaccine market and limits hospitals' choices of supplier.

"We've found that the financial incentives are insufficient, and there's lots of regulation in biological vaccine production because they are subject to contamination," Sloan said. "That's why there are so few manufacturers in the market."

An estimated total of 97 million shots will be available to Americans beginning in mid-October. This year, GlaxoSmithKline has been added to the list of suppliers, bringing the total number up to four. Chiron will be supplying between 18 and 26 million doses.

Student Health had to ration student vaccinations last year because of the shortages. This year all students will be able to receive free vaccinations.

An alternative form of vaccination for students who do not like shots will be FluMist, the nasal spray vaccine produced by MedImmune, Inc.

But FluMist has its own problems. "There are difficulties in getting people to take nasal sprays because Flumist uses live viruses, and this does pose a small risk," Engemann said. "It's been shown that the flu can be contracted like this, especially by children."

Student Health will be holding two clinics to help combat the flu. The first will be held Oct. 18 for people at high risk-medical students, health care workers on clinical rotation, people with chronic diseases such as diabetes or asthma and people with babies less than six months old in their households. The second, scheduled for Nov. 8, will be for all other individuals.