NEW YORK (Reuters) - New York City health officials scrambled to explain themselves on Thursday in the wake of media reports about bankers who got scarce H1N1 flu vaccines through their employers.

Members of Congress fired off letters demanding immediate explanations and the U.S. Centers for Disease Control and Prevention reminded state and city health officers of the need to make sure the most vulnerable people get shots first.

“I am concerned that the distribution of the vaccine is resulting in favored treatment for the privileged,” New Jersey Democratic Representative Frank Pallone said.

A shortage of H1N1 vaccines has frayed nerves, and public health departments across the country say they will not be able to meet the bulk of the demand until December or January.

The CDC estimates swine flu has infected more than five million people and it is documented as having killed 1,000.

The federal government, which is buying the vaccines and distributing them for free to 62 state and city health departments, says 35.6 million doses have been made and packaged since production began.

Connecticut Sen. Chris Dodd, a Democrat, released a letter to Health and Human Services Secretary Kathleen Sebelius saying he was “stunned” at the reports.

“I implore you to use whatever authorities you have to ensure that H1N1 vaccines already distributed but not yet used are promptly redirected to hospitals, schools, community health clinics, school-based health clinics, and pediatricians so that they can be made immediately available to at-risk members of the public as identified by the Department,” Dodd wrote.

CDC Director Dr. Thomas Frieden sent out a reminder to state and city health departments that distribute vaccine.

“I ask each of you to review your plans immediately and work to ensure that the maximum number of doses is delivered to those at greatest risk as rapidly as possible,” he wrote.

“I especially appreciate the many innovative ways you’ve found to reach them, including school-located vaccine clinics, special clinics for pregnant women, outreach to children with special needs, and making vaccine available to community- and faith-based organizations serving these high-risk populations.”

Close to 160 million people are in the priority groups to get vaccine first -- healthcare workers, pregnant women, children and adults under 65 with medical conditions, caregivers for infants too young to be vaccinated and people 24 and younger.

“When H1N1 vaccine first became available in the fall, we directed all available doses to pediatricians, OB-GYNs, community health centers, public and private hospitals,” New York City health department spokeswoman Jessica Scaperotti said in a telephone interview.

“As more vaccine became available we started to place small orders to providers that serve adults, including employee health centers.”

She said the city had given 800,000 doses to about 1,100 providers, with Lenox Hill Hospital, for example, getting 1,200 doses and banking firm Goldman Sachs getting 200 of the 5,300 doses it asked for, Scaperotti said.

She said 16 of the city’s 25 biggest employers had vaccine, including Columbia University, Citi Group and others, as well as the Federal Reserve Bank, which is not among the top 25 employers.

Morgan Stanley said it received 500 doses of the vaccine for its New York City locations and 500 doses for its Westchester location in suburban New York.

“We never thought we would receive doses ahead of area hospitals and once this was brought to our attention, we promptly donated the doses we received to a few area hospitals,” including Morgan Stanley Children’s Hospital in New York, a company spokeswoman said.