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. Since the 1980s, the government has protected vaccine makers against lawsuits over the use of childhood vaccines. The document signed by Sebelius last month grants immunity to those making a swine flu vaccine, under the provisions of a 2006 law for public health emergencies. It allows for a compensation fund, if needed. The government takes such steps to encourage drug companies to make vaccines, and it's worked. Federal officials have contracted with five manufacturers to make a swine flu vaccine. The last time the government faced a new swine flu virus was in 1976. Federal officials vaccinated 40 million Americans during a national campaign. A pandemic never materialized, but thousands who got the shots filed injury claims, saying they suffered a paralyzing condition called Guillain-Barre Syndrome or other side effects.