A C.D.C. spokeswoman said Dr. Alcabes’s estimates were incorrect because the new figures could not be used to calculate the total number of people with H.I.V. The C.D.C. does not know the total number but is expected to determine it later in the year.

The C.D.C., the federal agency responsible for tracking the AIDS epidemic in the United States, said its new monitoring system provided more precise estimates than were previously possible of new infections in specific populations. Infection rates among blacks were found to be seven times as high as for whites (83.7 per 100,000 people versus 11.5 per 100,000) and almost three times as high as for Hispanics (29.3 per 100,000 people), a group that was also disproportionately affected.

The C.D.C. has known of the new figures since last October, when the authors completed a manuscript and sent it to the first of three journals. But the agency refused to release the findings until they were published in a peer-reviewed medical journal. The first two journals rejected the authors’ request for a fast-track review.

The paper is being published in the Aug. 6 issue of The Journal of the American Medical Association. The journal and the disease centers had planned to release it at a news conference on Sunday at the opening of the 17th International AIDS Conference here. But the paper was released on Saturday because the embargo was broken. A number of leading health experts have criticized the agency for not releasing the information earlier. On Nov. 21, C.D.C. officials told AIDS advocacy groups and reporters that the data would be released soon.

In an editorial on June 21, The Lancet, an internationally prestigious journal published in London, severely criticized the disease centers for failing to release the information and said, “U.S. efforts to prevent H.I.V. have failed dismally.”

Dr. Gerberding, in defending the decision not to release the data earlier, said: “This paper has been scrutinized by some of the best statisticians in the country and is much better now than when we started this process. It was so complicated that even I, who has some expertise in this area, could not stand by it without making sure we had gone through the review process.”

She added, “This is one of those examples where getting the external review process to really scrutinize the paper, pick it apart, build it back up, has in my opinion fundamentally improved it.”