H1N1 vaccine linked to potentially fatal nervous system condition: study Researchers in Canada have found that for every million doses of the H1N1 pandemic vaccine that were administered in 2009/10 there were two extra cases of Guillain-Barré syndrome which can be fatal in extreme cases. The benefits of vaccination still outweighed the risks, they concluded as the risk of death from H1N1 in the region was one in 2,500. It was found the increased risk was between 12 per cent and three fold, due to small numbers involved. The disease, which can rapidly cause progressive muscle weakness and temporary paralysis, can be triggered by minor infections such as colds and sore throats. It can take a year to recover fully. The Health Protection Agency in Britain has examined rates of the disease here during and after the pandemic and found there was no increase in vaccinated people. The findings were published in the Journal of the American Medical Association. In Britain children who qualify for the seasonal flu vaccine on the NHS because they have serious asthma or other long-term conditions can now receive the first nasal spray vaccine, called Fluenz, instead of an injection.