Next fortnight is crucial to Boris Johnson’s chances of survival

“Most will get a mild form of the disease” was the mantra trotted out during the early daily briefings from Downing Street as we were pursuing the “acquiring herd immunity” strategy. Whilst this is true, Covid-19 is distinguished by causing severe symptoms in a minority. 

We all wish the Prime Minister a full and speedy recovery. 

This article presents the brutal facts as they relate to what we know to date in this epidemic of what it can do to a minority. We must all hope that medical science can find effective therapies to alleviate symptoms whilst the world waits for a vaccine.

Tom Whipple 

It was not, we can be fairly certain, the hospital handshakes that did it.

At the beginning of March — a month ago and a world away — Boris Johnson was criticised after saying that he had been going around hospitals greeting patients and, in defiance of the coronavirus, shaking them by the hand.

Today Mr Johnson is back in hospital for very different reasons, and there is neither defiance nor glad-handing.

As foolish as the handshakes may have been, it seems far more likely that his infection can be traced to a fortnight later and what could be called the “Cobra cluster”. On the day when Britain went into lockdown Neil Ferguson, the government’s leading adviser on disease modelling, was in Downing Street.

It turned out that he was also providing a less than theoretical lesson in disease spread — the next day he would announce that he had coronavirus. We will never know for certain if he was “patient zero” for the cabinet. We do know that in the days that followed Matt Hancock, the health secretary, Chris Whitty, the chief medical officer, and Dominic Cummings, Mr Johnson’s chief adviser, all went down with symptoms. And so, on March 26, did Mr Johnson.

We understand enough about the virus’s trajectory to know that most people who get over it easily do so in the first week in which their symptoms appear. As Mr Johnson compared notes with Mr Hancock, who was diagnosed on the same day, they would have not, initially, felt that dissimilar. Inside their bodies — most likely confined largely to their noses and throats — the coronavirus was reproducing, multiplying, and recreating the symptoms of a bad cold.

While Mr Hancock’s immune system was already containing and controlling the coronavirus, in Mr Johnson, for whatever reason, the infection was probably spreading to his lungs. And, about ten days after his symptoms began, the infection had worsened to such an extent that he had to go to hospital.

From the intensive care unit there are two routes out: death or discharge. According to very early data, both are equally likely. That bald statistic ignores both Mr Johnson’s circumstances, however — he is five years younger than the average British coronavirus patient in ICU — and the fact that the present statistics are based on only a fraction of cases. Most Britons who have gone into ICU with this virus are still there.

What we do know from experiences abroad is that the next fortnight is crucial. As more of Mr Johnson’s cells die they will be sloughed into his lungs, clogging them with fluid and debris. At the same time, doctors now believe, he will be in danger of a “cytokine storm”, in which the immune system overreacts, rushing in defensive cells and opening up blood vessels — causing damage and leading to yet more fluid on the lungs.

If he can battle that and come out the other side then, on average, we would expect to see Mr Johnson give a wave — albeit a feeble one — from the steps of St Thomas’ about 18 days after symptoms began, the weekend after next.

Patients who do not survive leave, on average, four days after that.