In March, he co-wrote a research paper setting out potential causes of anosmia in Covid-19 patients.

‘(Olfactory) sensory neurons (in the nose) are the cells that do the detecting of odour and stimuli and send those signals to the brain. If they die, then you don’t lose them forever. They can regenerate, but that takes a few weeks,’ he said.

‘The fact that the recovery (of the sense of smell) seems to be a bit quicker with Covid-19 started to make people think that maybe it’s not infecting the neurons themselves.’

This shifted attention away from neurons to different types of cells that can regenerate quickly. In particular, ones known as sustentacular cells, which provide support for the olfactory sensory neurons.