There were 118 deaths from the disease, which is an 11 percent mortality rate. Most of the deaths were patients older than 50.
The flu vaccine has been in very short supply.
"My hope is that the vaccine will come in such numbers that these issues will be soon forgotten, but right now, we're trying to allocate it as best we can, and it's really not an easy choice," said Dr. Jonathan Fielding, director of the L.A. County Department of Public Health.
An H1N1 vaccine clinic is open at the University of Southern California Lyons Center from 9 a.m. to 3 p.m., one of three clinics that the L.A. County health department opened on Wednesday.
Although doors opened at 9 a.m., people started lining up well before 5 a.m., prepared with chairs, blankets and reading material.
Carlos Galindo said he tried to get his son vaccinated on Tuesday, but it was too crowded, so on Wednesday, he showed up early and was ninth in line. By noon, the clinic's line was out the door and stretched to the USC football practice field.
"I think there's a bit of panic, which is sometimes driven by pictures and TV and media," said Dr. Larry Neinstein, USC Campus Health director.
"If you look over the years with the flu, when we have a large supply, you can't give the vaccine away. In years that there's a shortage, everybody lines up and lines up. It's kind of human nature," he said.
Health officials said they do not know when they'll have enough vaccine for everybody, and said their top priority right now is children under the age of 3, then pregnant women, then everybody else.
"I'm glad that this is available here," said mother Chandler Chang, who was able to get her 7-month-old child vaccinated.
Clinics are also open at Santa Monica College, 1900 Pico Blvd., from 9 a.m. to 1 p.m., and at the Hawaiian Gardens human resources building, 21815 Pioneer Blvd., from 11 a.m. to 7 p.m.
Hawaiian Gardens volunteers say they expect to vaccinate about 2,400 people Monday, but they admitted that supplies are running low, especially for the pediatric vaccine.
In Washington, Congress is holding a hearing on Wednesday on a bill that will guarantee sick leave to any worker who is asked to stay home because of swine flu. House Education and Labor Committee chairman George Miller says his measure would protect about 50 million workers with no paid sick leave.
Eyewitness News reporters Denise Dador and Gene Gleeson contributed to this report.