Boris Johnson faces up to two months watching his government from the wings, according to intensive care survivors who braced him for a long recovery.
Such an extensive period of bed-rest could put the Prime Minister out of action during the critical phase of the crisis, as cases peak.
Breathing problems prompted his transferal into the ICU at St Thomas' Hospital in central London last night, where he was given oxygen.
Downing Street today reassured the 55-year-old's condition was stable and he 'remains in good spirits', while not currently in need of ventilation.
Foreign Secretary Dominic Raab, who is deputising for the PM and has been handed extensive decision-making powers, including ones relating to national security, said he was confident his 'boss and friend' would pull through.
But when the 'fighter' PM does recover from the infection, he has been warned that much recuperation is required and will he not be able to immediately take back the reins.
The Prime Minister (pictured on Thursday evening), who was admitted to St Thomas' Hospital in London last night, was taken to intensive care at 7pm this evening
Mr Raab raised concerns as he was seen coughing leaving the Foreign Office to go to Downing Street this morning
Matt Dockray, 39, who was treated in intensive care for the disease, mapped out recovery path awaiting Mr Johnson on his discharge from hospital
Matt Dockray, 39, who was treated in intensive care for the disease, mapped out recovery path awaiting Mr Johnson on his discharge from hospital.
The father-of-one from Marlow, Buckinghamshire, told Good Morning Britain: 'There's still a long road of recovery, it takes about six to eight weeks, but you can sit here and tell the tale and fight this.'
Describing his own personal battle with the virus, Mr Dockray said: 'There was a point where you sort of started to lose hope and thought that was it, because you've seen this on the TV, you've seen the pictures of Italy.
'In my head that was the time to say "You've just got to fight as much as you can".'
Critical patients with coronavirus have described feeling physically drained as the infection saps energy levels.
Across the Atlantic, Mic Reich, 36, from Chicago, revealed how she still had not regained her stamina after symptoms surfaced in early March.
The patient, who does have an autoimmune disease, told the Chicago Tribune: 'The best way I can describe it is it’s like wearing a corset that’s too tight, while walking through the polar vortex.'
And survivors have also told of emotional bruising which takes a while to fade, with fears of infecting loved ones.
Scientists have not yet established how long it takes for patients to fully recover from Covid-19.
Some have seen symptoms linger for as much as eight weeks, according to reports.
But Prof Duncan Young, Professor of Intensive Care Medicine, University of Oxford, said that the recovery period of intensive care patients generally can be much longer than a month.
He said: 'In the UK the average hospital ward stay after a patient is discharged from an ICU (not COVID-19 related) is about 15 days but there is a very wide range and a quarter stay 48 days or more in the hospital after ICU discharge.
'In general the time in hospital depends on what co-morbidities a patient has, what the acute illness is that required ICU treatment, and the duration and intensity of ICU treatment.'
When the Prime Minister began self-isolating on March 27, he resolved to continue leading the government's coronavirus response from self-isolation in his Number 11 flat.
Insiders say he was reluctant to relinquish responsibility, a decision which has since been criticised.
In the event the PM is bed-bound following his treatment, Mr Raab will continue to keep his hand on the tiller and steer the government through the health crisis.
Mr Raab, who is also first secretary of state and outranks his fellow cabinet minister, assured the machine of government would continue to operate while the PM battled his virus.
The UK does not have a constitutional line of succession, but Number 10 revealed Chancellor Rishi Sunak would take over if Mr Raab also fell ill.
Mr Raab will not be able to hire and fire colleagues. But asked who will be in control of the nuclear deterrent and armed forces, the PM's spokesman said: 'In relation to national security matters the First Secretary of State and the Cabinet have the authority and the ability to respond in the Prime Minister's absence.'