ATLANTA The last time the government embarked on a major vaccine campaign against a new swine flu, thousands filed claims contending they suffered side effects from the shots. This time, the government has already taken steps to head that off.

Vaccine makers and federal officials will be immune from lawsuits that result from any new swine flu vaccine, under a document signed by Secretary of Health and Human Services Kathleen Sebelius, government health officials said Friday.

“The government paid out quite a bit of money,” said Stephen Sugarman, a law professor who specializes in product liability at the University of California at Berkeley.

Vaccines aren’t as profitable as other drugs for manufacturers, and without protection against lawsuits “they’re saying, ‘Do we need this?’” Sugarman said.

The move to protect makers of a swine flu didn’t go over well with Paul Pennock, a prominent New York plaintiffs attorney on medical liability cases. The government will likely call on millions of Americans to get the vaccinations to prevent the disease from spreading, he noted.

“If you’re going to ask people to do this for the common good, then let’s make sure for the common good that these people will be taken care of if something goes wrong,” Pennock said.