Six months after becoming infected with coronavirus, Laurence Lefèvre still has to sleep with a breathing aid: she is one of many who suffer from 'long Covid'. This complication of Covid-19 is not limited to older individuals - a study has shown that, when numerous Swiss army recruits developed coronavirus, one in five of these young men had symptoms for weeks. 'One in five lost more than 10% breath capacity', explains Jeremy Deuel, who led the research. Martina Fiserova, another long Covid sufferer, struggles with 'fatigue, nausea, dizziness, memory loss and states of confusion', three months after her initial infection. 'If just 1,,, 2… 5% of the population still have after-effect symptoms, we'll face a major public health problem', says one medical professional.