A Senate committee yesterday abruptly dropped plans to move legislation overhauling a program to compensate children injured by vaccines, thus raising questions about whether a bipartisan deal was unraveling.

The legislation would nullify hundreds of lawsuits claiming injury and send them to a fund established to handle the claims.

Sen. Judd Gregg (R-N.H.), chairman of the Health, Education, Labor, and Pensions Committee, said action was postponed because events in Iraq had pulled away Senate Majority Leader Bill Frist (R-Tenn.), who is a committee member and the bill's prime sponsor.

But Democrats said the postponement had more to do with objections lodged at the last minute by two of the four major manufacturers of vaccines.

Sen. Christopher Dodd (D-Conn.), who led negotiations for Democrats, said he is disappointed that the committee action was being postponed until after the upcoming Easter break.

Under the legislation, more than 200 lawsuits filed by families who believe their children were sickened by vaccines would be sent instead to a special federal fund.

Senators led by Frist say these cases always were intended for the Vaccine Injury Compensation Program, but lawyers had found a way to skirt the system.

The issue became contentious late last year when Republicans slipped the change at the last minute into homeland security legislation. Under pressure, lawmakers undid the move in subsequent legislation, but vowed to try again this year using standard legislative procedures.

Childhood vaccines are safe for almost all children, but a small number are injured each year. Under current law, injured families must file claims with the compensation fund, where cases are independently evaluated, before going to court. Average awards are just under $1 million.