The country has been left reeling by the news that Boris Johnson has been admitted to intensive care after his condition worsened.
The Prime Minister was diagnosed with coronavirus on March 27, and immediately began self-isolating in his flat at Downing Street.
Matt Hancock, the Health Secretary, was also diagnosed on the same day, but while he was back at work after just a week, Mr Johnson’s condition has continued to deteriorate.
On Sunday evening, doctors were concerned enough to admit the Prime Minister to St Thomas’ Hospital in London for routine tests after his temperature and cough showed no signs of improvement, and on Monday night he was moved to intensive care, a sign that he may soon need ventilation.
A ventilator is required when a patient is struggling to breathe for themself, and is essentially life support. Mr Johnson is currently receiving extra oxygen, but if necessary he will be sedated and a machine will breathe for him until he is well enough to breathe again for himself.
The statistics coming out of intensive care are lagging behind the daily updates, so it is difficult to draw definitive conclusions about the survival or progression rates of those admitted to intensive care units.
Figures released by the Intensive Care National Audit and Research Centre (ICNARC) over the weekend showed that there have been 2,621 admissions to critical care in Britain since the coronavirus epidemic began.
Early analysis of ICNARC data from 2,249 of those admissions shows that 346 patients have died and 344 have been discharged with a clean bill of health. The average time for each scenario was four to five days.
While that may look like a 50:50 survival rate, there are 1,559 people still in intensive care, so that brings the chance of death or discharge within five days down to about 15 per cent.
Of the 690 intensive care patients whose outcome was known, those who needed ventilation within the first 24 hours of intensive care had the worst outcomes, with just over 30 per cent surviving, compared to 70 per cent of those who did not need such early respiratory help:
Professor Mike Grocott, a consultant in critical care medicine and vice president of the Royal College of Anaesthetists, said: “It’s important to understand that being in an intensive care unit isn’t all about being on a ventilator.
“Intensive care is where life support takes place. This involves a highly experienced multi-disciplinary team of doctors, nurses and support staff with a wide variety of skills.
“They make use of highly sophisticated monitoring equipment to keep track of the patient’s blood oxygen levels, as well as blood pressure and heart rate.”
A total of 51,608 people have now been diagnosed with coronavirus in Britain, the vast majority of whom were tested after being admitted to hospital with severe symptoms.
People with mild symptoms are being asked to self-isolate and ride out the illness at home, so it is reasonable to assume that those tested represent the most serious cases.
But one striking detail of the ICNARC figures is that very few people who are testing positive in hospital are ending up in intensive care.
Comparing the 2,621 admissions to intensive care by Friday April 3 to the cumulative cases – 38,168 – on the same day, it appears just six per cent of people with serious symptoms are ending up in intensive care.
That figure is interesting because it suggests that the modelling by Imperial College, which suggested 30 per cent of people admitted to hospital with coronavirus would need intensive care, was overly pessimistic. In contrast, Sweden has suggested that it is closer to five per cent, which is more in keeping with the real-time data.
Given the number of deaths by Friday – 3,605 – the figure also suggests that many people who have died were never admitted to intensive care.
If just 346 of those who died by Friday had been admitted to intensive care , as suggested by the report, then fewer than one in 10 deaths are happening in critical care units – which could indicate that many people are dying on other wards, perhaps from other conditions, while also testing positive for coronavirus.
It is possible the discrepancy lies in not all trusts reporting their intensive care data, but the ICNARC report says that the figures come from its “Case Mix Programme” and include all NHS adult, general intensive care and combined intensive care/high dependency units in England, Wales and Northern Ireland, plus some specialist and non-NHS critical care units.
There could also be a lag in the time between deaths and the reporting of intensive care figures, and the ICNARC report authors warn that “due to the relatively low proportion of patients that have completed their critical care, all outcomes should be interpreted with caution”.
Data coming from China which has looked at the progression of the disease showed that, for the most serious cases, the median time to discharge was 22 days, while the average time to death was 18.5 days. If the figures hold true for Britain, that suggests that Mr Johnson may not be discharged until the end of April.
The average duration of fever was about 12 days in survivors, which was similar in non-survivors, but nearly half of people still had a cough on discharge. Shortness of breath got better around 13 days for those who got well after infection.
For those who died from the illness, sepsis kicked in around day nine, while acute kidney or heart injury occurred by day 15, as shown in the table below.
It was also discovered that patients who survived were infectious for up to 37 days, far longer than previously thought.
Compared with survivors, patients who died were more likely to be older, with an average age of 69 years as opposed to 52 years.
The latest intensive care data for Britain continues to show that the virus seems to disproportionately affect men, with just 36 per cent of beds taken by women.
Some experts believe the sex imbalance relates to a higher prevalence of smoking or chronic alcohol use among men, while others think men are more likely to have underlying health conditions, such as heart disease and diabetes, that make them more vulnerable to an infection.
Professor Derek Hill, Professor of Medical Imaging, at University College London (UCL), said: “One of the features of Covid-19 in all countries seems to be that many more men become seriously ill than women – especially in the over-40 age group.
“Also we know that people under about 60 seem to have a higher chance of making a recovery from critical illness with Covid-19 than older people. But there is no doubt this turn of events means Boris Johnson is extremely sick. It seems clear that the Prime Minister went to hospital because he had difficulty breathing.”
St Thomas’, where Mr Johnson is being treated, has seen some of the highest numbers of coronavirus patients of any hospital in Britain and is a specialist centre for advanced respiratory support.
Dr Alison Pittard, Dean of the Faculty of Intensive Care Medicine, said: “The experience will give him a special insight into what intensive care is and its importance for the future. I know he will receive the highest quality of care.”