A nerve disease linked to viral and bacterial infection will be carefully looked out for after the swine flu vaccine is administered nationwide this autumn.
Health Protection Agency (HPA) chiefs stressed that the risk of developing Guillain-Barre syndrome will not be increased by receiving the vaccine, but that it can appear in the weeks after a flu-like illness.
The syndrome attacks the nervous system and can cause temporary paralysis, affecting an estimated 1,500 people in UK every year. Most people make a full recovery within a few weeks or months with no after effects, but there is a possibility of permanent nerve damage.
From October, over 13 million people nationwide will receive the swine flu jab with the normal seasonal vaccine expected to be given out at the same time.
A HPA spokesman said: "Guillain-Barre syndrome has long been identified as a potential adverse event that would require enhanced surveillance following the introduction of a pandemic vaccine but there is no evidence to suggest there is an increased risk of Guillain-Barre syndrome from this vaccine.
"There is robust evidence that no increased risk of Guillain-Barre syndrome arises from seasonal flu vaccination."