The Imperial College London study that overnight changed UK govt’s COVID-19 strategy

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UK Prime Minister Boris Johnson unveiled much more stringent measures to tackle the coronavirus outbreak after new research indicated a quarter of a million people would have died under previous plans to control the spread of pandemic. US News reports that the modelling study, by Imperial College London, and led by Professor Neil Ferguson, an expert on the spread of infectious diseases helped change the UK government’s position, according to those involved with the decision. The government said it had accelerated its plans “the advice of the experts”.

Some of the findings of the research are that if no action had been taken against the virus it would have caused 510,000 deaths in Britain and 2.2m in the US. “The epidemic is predicted to be broader in the US than in the UK and to peak slightly later. This is due to the larger geographic scale of the US, resulting in more distinct localised epidemics across states,” the study said.

The report says the UK government’s previous plan to control the virus involving home isolation of suspect cases, but not including restrictions on wider society, could have resulted in 250,000 people dying. The approach would “likely result in hundreds of thousands of deaths and health systems (most notably intensive care units) being overwhelmed many times over,” the study said.

The study said that a strategy of draconian restrictions was the best way to tackle the virus. “We therefore conclude that epidemic suppression is the only viable strategy at the current time. The social and economic effects of the measures which are needed to achieve this policy goal will be profound,” the study said. “Many countries have adopted such measures already, but even those countries at an earlier stage of their epidemic (such as the UK) will need to do so imminently.”

The study said that 9% of people in the most vulnerable age group, 80 and older, could die if infected.

The report says the health impacts from coronavirus are comparable to the devastating 1918 influenza outbreak. “The last time the world responded to a global emerging disease epidemic of the scale of the current COVID-19 pandemic with no access to vaccines was the 1918-19 H1N1 influenza pandemic,” the study said.

To curb the epidemic, the restrictions must in place until a vaccine was found in 12 to 18 months, the research said. “The major challenge of suppression is that this type of intensive intervention package – or something equivalently effective at reducing transmission – will need to be maintained until a vaccine becomes available (potentially 18 months or more) – given that we predict that transmission will quickly rebound if interventions are relaxed,” the study said.

A commentary has looked at what we know so far about the new virus. The researchers, led by Professor Sir Roy Anderson at Imperial College and Professor Deirdre Hollingsworth at the University of Oxford‘s Big Data Institute, also suggest what can be done to minimise its spread and its impact.

Hollingsworth said: “Completely preventing infection and mortality is not possible, so this is about mitigation. Our knowledge and understanding of COVID-19 will change over time, as will the response. High quality data collection and analysis will form an essential part of the control effort. Government communication strategies to keep the public informed will be absolutely vital.”

Vaccine development is already underway, but it is likely to be at least a year before a vaccine can be mass-produced, even assuming all trials are successful. Social distancing is therefore the most important measure, with an individual’s behaviour key. This includes early self-isolation and quarantine, seeking remote medical advice and not attending large gatherings or going to crowded places. The virus seems to largely affect older people and those with existing medical conditions, so targeted social distancing may be most effective.

Government actions will be important, including banning large events such as football matches, closing workplaces, schools and institutions where COVID-19 has been identified, and making sure that good diagnostic facilities and remotely accessed advice, like telephone helplines, are widely available. Ensuring the provision of specialist healthcare is also vital. The researchers warn, however, that large-scale measures may only be of limited effect without individual responsibility. All measures, of course, will have an economic impact, and some stricter measures, such as shutting down entire cities, as seen in Wuhan in China, may be less effective in Western democracies.

The aim of these social distancing measures is to “flatten the curve” of the infection, slowing the spread and avoiding a huge peak in the number of new infections. Flattening the curve can avoid overwhelming health services, keep the impact on the economy to within manageable levels and effectively buy more time to develop and manufacture effective vaccines, treatments and anti-viral drug therapies.

Anderson said: “Government needs to decide on the main objectives of mitigation – is it minimising morbidity and associated mortality, avoiding an epidemic peak that overwhelms health-care services, keeping the effects on the economy within manageable levels, and flattening the epidemic curve to wait for vaccine development and manufacture on scale and antiviral drug therapies. We point out they cannot achieve all of these – so choices must be made.”

The researchers highlight that wider support for the health service and health care workers during an epidemic is vital in any case – during the Ebola epidemic in 2014-15, the death rate from other causes like malaria and childbirth rose sharply due to overwhelmed health services. The number of deaths indirectly caused by Ebola was higher than the number of deaths from Ebola itself.

While much has been made in the media of a number of “superspreading” events, where one infected individual has inadvertently spread the disease to many others, the authors warn that there are superspreading events in every epidemic, and care should be taken not to make too much of these.

Containing the spread of an infectious disease relies on keeping the “reproduction number,” R0, the number of people infected by each infected person, below 1, when the pathogen will eventually die out. If R0 rises above 1, each infected person infects more than one other person, the pathogen will spread. Early data from China suggests that the R0 for COVID-19 could be as high as 2.5, implying that in an uncontained outbreak, 60% of the population could be infected. There are many unknowns in any new virus, however, and with COVID-19, it is not currently clear how long it takes for an infected person to become infectious to others, the duration of infectiousness, the fatality rate, and whether and for how long people are infectious before symptoms appear. It is also not currently clear if there are cases of COVID-19 which are non-symptomatic.

In comparisons with influenza-A (usual seasonal flu) and SARS, it currently seems likely that the epidemic will spread more slowly, but last longer, which has economic implications. Seasonal flu is generally limited by warmer weather, but as it is not known if this will affect COVID-19, the researchers say it will be important to monitor its spread in the Southern Hemisphere. Researchers will continue to collect and analyse data to monitor spread, while ongoing clinical research into treating seriously ill patients is also necessary.

One of the main priorities for researchers and policymakers will be contact tracing, with models suggesting that 70% of people an individual has come into contact with will need to be traced to control the early spread of the disease. The authors say other priorities include shortening the time from symptom onset to isolation, supporting home treatment and diagnosis, and developing strategies to deal with the economic consequences of extended absence from work.

Author Professor Hans Heesterbeek from the department of population health sciences at the University of Utrecht said: “Social distancing measures are societally and economically disruptive and a balance has to be sought in how long they can be held in place. The models show that stopping measures after a few months could lead to a new peak later in the year. It would be good to investigate this further.”

Mark Gallagher, a UK consultant cardiologist, is at home with a temperature of 38 and is pretty certain he has COVID-19. But, says a report in The Guardian, the National Health Service (NHS) will not test him for it. Instead, he has paid for a test kit from a private UK clinic and a colleague in China is sending him another. Gallagher has been in and out of his London hospital every day for the last 28 in a row. In the past couple of weeks he saw maybe 70 people in outpatients, he said.

The report says he cannot understand why the NHS will not test him or other healthcare workers who are put at risk by their work and risk infecting other vulnerable patients in turn, as well as their families. “The policy is that I don’t need to be tested and even the people who have been in contact with me aren’t going to be tested,” he said. “They are abandoning the basic principles for dealing with an epidemic, which are to test whenever possible, trace contacts and contain. Almost all individual physicians I know feel that what they are doing is wrong.”

Although the self-isolation policies announced by the prime minister on Monday were a slight improvement, Gallagher feels they are not enough. “It could be eliminated if we worked really hard, but there is a policy of surrender,” he said. “Our in-house occupational health and infection control teams are competent and hard-working and the infection control people have been at excellent and brave, circulating on the affected wards,” he said.

The report says the UK should be learning the lessons, he says, from the sharp lock-down in Hubei – and the very energetic contact tracing that has taken place in South Korea, Hong Kong and Singapore. The approach of the UK falls far short of that.

Full US News report

Imperial College London study

University of Oxford material

The Lancet comment

Full report in The Guardian

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