In February 2011, THL concluded that there is a clear connection between the Pandemrix vaccination campaign of 2009 and 2010 and the narcolepsy epidemic in Finland. The probability of developing narcolepsy was determined to be nine times higher in those who received the Pandemrix vaccination than those who didn't. A total of 152 cases of narcolepsy have been found in Finland during 2009–2010, and ninety percent of them had received the Pandemrix vaccination.