The Science Behind Number 10's Tougher COVID-19 Strategies

Peter Russell and Tim Locke

March 17, 2020

Editor's note, 28th April 2020: The Imperial College London study in Lancet Infectious Diseases has been corrected. The paper warned of uncontrolled spread of the disease causing as many as 510,000 deaths. However, Retraction Watch alerted the research team to the withdrawal of a preprint it cited. Azra Ghani, co-corresponding author of the paper told Retraction Watch "the epidemic has now moved on" and they are "confident that the results would still hold".

Research quantifying how COVID-19 was likely to spread, the effect on the NHS, and possible mortality rates, helped prompt Number 10 to take tougher action to combat the virus, it was revealed.

An important component of that evidence came from research conducted by Imperial College London (ICL), which uncovered a bleak assessment of how the pandemic was likely to develop.

In today's other developments:

  • NHS England announced the suspension of all non-urgent operations from 15th April. This could free-up 15,000 beds. Early discharge of eligible patients could free-up another 15,000 beds.

  • Government Chief Scientific Adviser Sir Patrick Vallance told the Commons Health Committee that deaths of 20,000 or fewer people linked to coronavirus would be a "good outcome".

  • NHS England officials promised more protective equipment for staff soon after being asked about distressing accounts of a lack of PPE protective gear in A&E.

Prime Minister Boris Johnson told a Downing Street news conference: "We may need to go further and faster" on measures to slow the spread of the virus. "This enemy can be deadly but it is also beatable,” he said. “We have the resolve and the resources to win the fight."

He added: "We're doing all we can, and as quickly as we can to increase the capacity of the NHS, that means more testing, more beds, more ventilators, and more trained staff. It means greater support for NHS and other staff, and it means much better data, and much better technology."

The PM was asked again why schools had not been closed. “We’re keeping that under continuous review,” he said.

Strategies for Dealing With COVID-19

By crunching the numbers for coronavirus, ICL scientists said they were able to paint a clearer picture of its spread and risk. In turn, this would allow them to give governments a clearer insight into how events might unfold. 

"Now that we have moved from a containment phase in the UK to a delay phase and potential mitigation, we're producing detailed scenarios of what might happen to inform healthcare planning," said Prof Azra Ghani, chair in infectious disease epidemiology at ICL.

The researchers examined the likely effects of three strategies:

  • Suppression, in which authorities tried to limit the number of cases

  • Mitigation, in which the policy was to slow the spread of the virus and give the health service space to cope

  • Do nothing and allow the virus to take its course in the population

Modelling found that in an unmitigated epidemic, approximately 510,000 deaths could occur in the country.

Even in a mitigation scenario, assuming that all patients were able to be treated, vastly exceeding the surge limits for general hospital wards and ICU units by about 8-fold, the mortality rate would still be in the order of 250,000, they said.

"We therefore conclude that epidemic suppression is the only viable strategy at the current time," the researchers said. "The social and economic effects of the measures which are needed to achieve this policy goal will be profound," they warned.

That analysis cued Prime Minister Boris Johnson, who appeared sombre at his first regular daily on-camera briefing on Monday, to appeal for social distancing strategies, including a boycott of pubs, clubs, cinemas, theatres and other venues where large numbers of people gather together.

Older people, in the 70+ age bracket, as well as those with serious comorbidities, were also put on notice that they could be just days away from a lengthy period of self-isolation, although the nature of what that entails varies across the UK nations.

Some commentators have questioned why most schools remain open, although Sir Patrick Vallance, the Government's chief scientific adviser, said that policy remained subject to review.

Dr Michael Head, senior research fellow in global health at the University of Southampton, told the Science Media Centre: "The publication of this evidence that is clearly informing UK policy is important and useful.

"The Imperial modelling show various scenarios that could happen with and without ongoing revisions of the measures that will need to be put in place over the coming weeks and months."

Dr Tim Colbourn, associate professor of global health epidemiology and evaluation at University College London, described the study results as "sobering". He said there were "very tough times ahead as the policy option that reduces the most deaths involves school and university closures and social distancing measures over 18 months for two-thirds of the time or more".

He added that one "clear message" was the "need to massively increase the number of ICU beds in the NHS from the current 5000, which looks so frighteningly few".

Testing for Frontline Health Workers Promised

In other developments so far this week, healthcare workers with early symptoms of COVID-19 are set to be tested, the Government confirmed.

The announcement followed concerns that too few tests were being carried out on NHS staff.

Earlier this week, the World Health Organisation (WHO) said some countries were not doing enough testing.

At a news conference last night, following a meeting of the Government's emergency COBRA committee, Prof Chris Whitty, the Government's chief medical adviser, said the intention was to test healthcare and other critical workers with early symptoms as quickly as possible.

"If they end up actually having the right symptoms but in a sense the wrong disease – or good disease, but not coronavirus – then they will be able to go back to work, which is good for the NHS and good for society. If they have got it, at least you know they've got it and they're not going to get it again," he said.

It was "a very strong incentive to get this out as fast as we can possibly manage it," Prof Whitty added.

Some scientists and health bodies had called for more testing to be carried out. Their voice was given added impetus by Dr Tedros Adhanom Ghebreyesus, director general of the WHO, who said yesterday: "We have a simple message for all countries: test, test, test – test every suspected case."

Alan McNally, professor in microbial evolutionary genomics at the University of Birmingham, commented: "Positive patients should be isolated and there needs to be a sustained practice of testing, including priority testing for health care workers."

The Doctors' Association UK, which had lobbied for testing frontline health workers, welcomed the announcement. Co-founder, Dr Samantha Batt-Rawden, said: "Healthcare workers in the NHS, especially those working in intensive care units, are putting themselves at risk every single day. Yet the willingness of those on the frontline to put themselves in harm's way to help treat patients shows no bounds. It truly is 'all hands on deck'.

"Doctors have been calling for testing of frontline NHS staff, not because it is of any benefit to them, but because a negative test will allow those needing to self-isolate to return to work quicker to serve patients. This is a real testament to our incredible NHS which this country is so lucky to have."

Editor's note, 17th March 2020: This article was updated with the latest developments.


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