The government-funded vaccine is being distributed to states, where health departments decide where to send the limited doses. In New York, health officials are allowing businesses with on-site medical staff to apply for the vaccine.

Doctors for large companies can ask for the vaccine along with other doctors but must agree to vaccinate only high-risk employees like pregnant women and those with chronic illnesses, said Jessica Scaperotti, a spokeswoman for New York City's Department of Health and Mental Hygiene.

Last month, the city began offering vaccine to schoolchildren, as well as the offices of pediatricians and obstetricians that asked for it. Scaperotti said only half of the pediatricians in New York City had requested vaccine.

She called the large employers "a great avenue for vaccinating people at risk."

But a critic said Wall Street firms should not have access to the vaccine before less wealthy Americans.

"Wall Street banks have already taken so much from us," union official John VanDeventer wrote on the Service Employees International Union Web site. "They've taken trillions of our tax dollars. They've taken away people's homes who are struggling to pay the bills. But they should not be allowed to take away our health and well-being."

The swine flu vaccine has been in short supply nationwide because of manufacturing delays, resulting in long lines at clinics and patients being turned away at doctor's offices. The vaccine started trickling out in early October, and there are now nearly 36 million doses available.

The Centers for Disease Control and Prevention does not review and sign off on the decisions of state and city health departments as to which doctor's offices and businesses will be sent vaccine doses, spokesman Tom Skinner said.

The CDC director, Thomas Frieden, however, did send a letter yesterday to state and local health departments asking them to review their distribution plans and make sure the vaccine is getting to high-risk groups. Frieden said any decisions that appeared to direct vaccine outside priority groups "have the potential to undermine the credibility of the program."

The agency has set guidelines on which patients should be at the front of the line: children and young people through age 24, people caring for infants under 6 months, pregnant women, health-care workers, and adults with health conditions such as asthma and diabetes.