Swine flu has had greater impact on blacks and Hispanics, according to records from the Boston Public Health Commission and Chicago Department of Public Health.

A Chicago study found blacks and Hispanics were four times more likely to be hospitalized due to swine flu than whites. Boston health officials released similar numbers — more than three of every four people impacted by swine flu were either black or Hispanic.

The findings are of relatively small sample sizes, health officials said. It will take much longer to get definitive data on swine flu’s racial impact.

“We don’t know if it’s a genetic predisposition that’s greater in Hispanic or blacks,” said Dr. Philip M. Tierno, Jr., director of clinical microbiology and immunology at New York University’s Langone Medical Center. “We think it may have to do with cohorting in large groups—individuals who live in large buildings where many families live and interface.”

New York City health and government officials are already making preparations to combat the infectious disease. New York City Mayor Michael Bloomberg announced Wednesday that all school students would receive free vaccinations once they become available in mid-October.

The city’s top health official was unaware of data on swine flu’s impact on different racial groups.

“No evidence that I know of that blacks and Hispanics are more likely to have a severe infection if they have infection,” said Thomas Farley, New York City Health Commissioner.of the flu’s impact. “If [blacks and Hispanics] had reduced access to medical care, it might be more difficult for them to get medical care.”

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