BOSTON -- It's technically still summer, but some doctors say they're already getting inundated with calls from people who want to get their flu shots before any problems arise.

Last year, an unexpected shortage of influenza vaccines led to long lines at some health clinics. Health officials are working to avoid another flu shot crisis this year, reported WCVB-TV in Boston.

Pediatrician John Cohen has flu vaccines for his young patients ready to go.

"We've had such trouble for the last two years. I'm sort of waiting to see what sort of disaster will happen this year," Cohen said.

Last year, Cohen had plenty of flu vaccine on hand, but they were from Chiron. When regulators shut down Chiron after discovering contaminated vaccine, most of his supply went unused. This year, he's ordering 20 percent fewer vaccines.

"The problem about vaccines in the United States is the system for production and distribution is broken," Cohen said.

But while many areas were dealing with a flu shot shortage last year, some fared relatively well.

"It took a little longer to get here, but by December, we had the usual number of doses," said Dr. Susan Lett, of the Massachusetts Department of Public Health. "We hope it will be better than last year. It's going to be delayed again, and because of that, we're going to prioritize vaccine."

The Centers for Disease Control and Prevention want to make sure those with the greatest flu risk get their shots first. Flu vaccines will be limited until Oct. 24 to anyone over 65, children under 2, pregnant women, health care workers and people with compromised respiratory systems. And this year, the high-risk group includes Hurricane Katrina victims living in shelters, since such conditions are ripe for communicable diseases.

"The tragedy affecting those on the Gulf Coast could potentially place evacuees at risk for influenza and pneumococcal infection due to crowded living conditions," said Dr. William Schaffner, of the National Foundation for Infectious Diseases.

Last year's demand has more companies getting into the flu vaccine business, but their influence won't be felt much this year.

"I am not optimistic in the least. I think that our vaccine supply this year will be equal to or less than last year," Cohen said.