As soon as Michael told me he’d got it, I knew I had to self-isolate. But first, I had to go to my studio to bring home my work. I noticed as soon as I started walking that I was air hungry. Uh-oh. It’s that quick. Already I’m not breathing so well. From the little I’ve read, I’ve understood that this is a disease which attacks the lungs. Whatever happens, people say, don’t let it go to your lungs.

Even I, who know nothing, know that we have five vital signs. At some point, probably researching for some play or film – it’s the only way I learn anything – I picked them up by heart. Temperature, heart rate, blood pressure, respiratory rate and oxygen saturation – that’s the measure of how much oxygen the blood is carrying. In a normal person it’s around 100 per cent. So, when it drops below 100, when the blood isn’t carrying enough oxygen to the lung, you start to worry.

Except – and this is where things get weird – doctors are already noticing that with this virus the rules don’t apply.

Doctors normally feel compelled to resort to ventilators when patients have oxygen saturation counts in the 80s, because by then they’re gasping for air. Only with this disease, they’re not. One doctor in New York has taken a picture of a woman lying on her belly with oxygen saturation of 54, and she’s chattering away on her mobile phone. What the hell is going on? People who should look ill are looking fine, and nobody understands why. There’s no correlation between oxygen saturation and how much oxygen is reaching the vital organs.

What the fuck?

Another doctor is quoted as saying: ‘The question is whether this vital sign we’ve been relying on for decades has been lying to us.’

He adds: ‘It’s very humbling in the twenty-first century with all the scientific advances we’ve made, and we just don’t really know the answer.’

*

OK, so it may be humbling for the medics, but for me and people like me, a better word is ‘alarming’.

‘It doesn’t resemble any other disease,’ says another doctor. ‘You have to go back to HIV/Aids to find a virus so little understood.’

I mooch around our house for a couple of days, pretending to work, but by Friday I’m feeling really terrible. In the pageant of random symptoms which will soon follow, there’s only one symptom that will remain permanent throughout. That’s exhaustion.

By nightfall, I’ve crawled into bed and forgotten what energy is.