Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

One of the most notorious was the influenza virus responsible for the 1918 pandemic, which caused permanent and profound damage to the dopamine neurons of the brain and central nervous system. (While it’s long been assumed that influenza cannot cross the blood-brain barrier, some scientists now think that it can). An estimated five million people worldwide were hobbled by a form of extreme exhaustion known as “sleepy sickness” or “encephalitis lethargica”.

Among those who survived, many remained in a state of suspended animation. “They neither conveyed nor felt the feeling of life; they were as insubstantial as ghosts, and as passive as zombies,” wrote Oliver Sacks in his 1973 memoir Awakenings. He described patients remaining in this stupor for decades until being revived by the drug L-DOPA, replenishing levels of the neurotransmitter dopamine. (Read more about why the 1918 flu was so deadly).

David Nutt, professor of neuropsychopharmacology at Imperial College London, says he himself treated many patients in the 1970s and 1980s who had suffered from severe clinical depression ever since the 1957 influenza pandemic in the UK.

“Their depression was enduring and it was solid – it was if their emotional circuits had all been switched off,” he says, warning that we could see the very same thing happen again, but on a much larger scale. “People who are discharged from the ICU with Covid-19 need to be monitored systematically long-term for any evidence of neurological damage – and then given interventionist treatments if necessary.”