some cases may be triggered by the influenza virus and potentially influenza vaccine. an increased incidence of guillain–barré syndrome followed influenza immunization that followed the 1976 swine flu outbreak (h1n1 a/nj/76); 8.8 cases per million recipients developed the complication. since then, close monitoring of cases attributable to vaccination has demonstrated that influenza itself can induce gbs. small increases in incidence have been observed in subsequent vaccination campaigns, but not to the same extent. the 2009 flu pandemic vaccine (against pandemic swine flu virus h1n1/pdm09) did not cause a significant increase in cases. it is considered that the benefits of vaccination in preventing influenza outweigh the small risks of gbs after vaccination. in fact, natural influenza infection is a stronger risk factor for the development of gbs than is influenza vaccination and getting the vaccination actually reduces the risk of gbs overall by lowering the risk of catching influenza. even those who have previously experienced guillain–barré syndrome are considered safe to receive the vaccine in the future. nevertheless, in the united states gbs after seasonal influenza vaccination is listed on the federal government's vaccine injury table and compensation may be available through the national vaccine injury compensation program. other vaccines, such as those against poliomyelitis, tetanus or measles, have not been associated with a risk of gbs.