The provision shielded manufacturers such as Eli Lilly and Co. from being sued over harm caused by a mercury-based vaccine ingredient called thimerosal.

Supporters said the liability protections were necessary because lawsuits alleging harm from thimerosal have bypassed a federal vaccine injury compensation fund set up in 1986.

The fund was established in part to encourage companies to stay in the vaccine business because vaccines benefit the public good. Lilly argued that lawsuits alleging injury due to vaccine ingredients should also go through the federal fund.

The provision to protect companies from being sued over vaccine ingredients had passed Congress as one of several measures tucked into last year's homeland security legislation at the last minute, sparking an uproar that nearly derailed that bill.

"This provision was added in the dark of night, clearly as a payback to powerful political supporters, and it had no place in legislation intended to protect American families," said Michigan Democrat Sen. Debbie Stabenow, who had pushed for the repeal.

The spending bill passed Thursday repealed that language.

No scientific studies have found a connection between thimerosal and autism.

Lilly had argued that the congressional measure would protect vaccine makers from meritless lawsuits.

"We're disappointed by the decision to repeal the vaccine ingredient provision. However, we agree that process by which the legislation was enacted was not desirable," Sagebiel said.

The company hopes Congress will pass similar language to block lawsuits over vaccine ingredients as part of broad vaccine legislation later this year, he added.