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expert reaction to government having moved to delay phase of COVID-19 plan

The government has announced that the UK is moving into the delay phase of the coronavirus response.


Comments sent out on Saturday 14 March

Dr Adam Kucharski, Associate Professor in Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, said:

“A couple of key takeaways from our analysis1 of early COVID-19 dynamics in Wuhan:

“We estimated that the control measures introduced there – unprecedented interventions that will have had a huge social and psychological toll – reduced transmission by around 55% in space of 2 weeks.

“There’s evidence that the vast majority of the population is still susceptible in Wuhan – we estimated around 95% at end of January.  As soon as control measures are lifted, there is the risk of new introduced cases – and another outbreak.

“It’s easy to say ‘let’s just do what Wuhan did’, but the measures there have involved a change to daily life that really has been unimaginable in scale and impact.  And as we’ve seen, China cannot sustain them indefinitely.

“Countries like Hong Kong and Singapore, which for so long have managed to contain COVID-19, now seem to be seeing a rise in transmission2, as infections continue to be introduced.

“There isn’t going to be an easy solution to COVID-19.  Among some extremely difficult options, we have to pick the most effective, sustainable way to minimise risk of overwhelming health system – and impact on the people most at risk.”


Dr Stephen Griffin, Associate Professor at Leeds Institute of Medical Research, University of Leeds, and chair of the Virus Division within the Microbiology Society, said:

“The outbreak in the UK is still at a relatively early stage. In terms of confirmed cases, it is true that this is similar to the numbers seen in Italy a few weeks ago – notably, the actual number of infections is likely to be significantly higher.   However, until we start to see a more rapid, exponential increase in cases, it is difficult to predict the trajectory of how this epidemic will evolve.  Whilst the dramatic steps taken by China have effectively reduced the number of new daily infections currently, other countries such as Singapore and South Korea have taken a more targeted approach that has, for example, allowed schools and shops in Singapore to remain open.  Thus, it does appear feasible to stem the tide of this virus without fully resorting to draconian measures.


“However, targeted approaches rely upon extensive, wide-ranging testing capacity in order to make real-time strategic decisions over which new control measures might be implemented.  The UK is currently ramping up its testing capacity, but the scope of this will likely need to be further increased.  Such efforts could be aided by a combined effort across public health, NHS and academic quarters, such as that mobilised during the Ebola outbreak in West Africa.”


Comments sent out on Thursday 12 March

Dr Tom Wingfield, Senior Clinical Lecturer and Honorary Consultant Physician, Liverpool School of Tropical Medicine, said:

“Although we have divided our response to COVID-19 into distinct phases, there is much overlap and complementarity between containment and delay.  The coordinated efforts of specialist units to isolate and care for the early cases in the UK, combined with PHE’s contact tracing and screening, was appropriate and commensurate to the risk at the time.  It is noteworthy that the majority of new cases during this containment phase were in returned travellers who had recently entered the country rather than within UK contacts of existing cases.  The subsequent increase in new cases we have since seen has predominantly been driven by within UK transmission.

“The transmissibility of COVID19, including by those with only very mild or barely noticeable symptoms, meant that containment was not possible.  Therefore, the move to a delay phase is proportionate.  Delaying spread is essential to minimise the impact on an already overburdened health service and defray some of the economic impact of the epidemic.  The social impact of further self-isolation and social distancing is likely to be severe and include loneliness, especially for vulnerable groups.  It is hoped that COVID19 might exhibit seasonality with less transmission in the warmer summer months of the northern hemisphere, which would be helped by delaying the epidemic curve.

“As case numbers and community transmission increase in the UK, the government has already mentioned further mitigation measures it may take including social distancing, household isolation, and protection of vulnerable groups.  The scale of those measures and how they may balance mitigation of the competing social, economic, and health impacts of COVID-19 in the UK remains to be seen.

“In the meantime, it is vital that we all take responsibility for protecting ourselves and each other by washing our hands regularly, self-isolating where appropriate, and keeping calm.”


Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:

“Any efforts to control the rate at which this virus spreads through our community are welcome.  Personal actions and changes in behaviours will slow the virus, if we all play our part.  But I am concerned that the government advice on self isolation doesn’t go far enough.  There is emerging data that suggests that in as many of 70% of cases the infection will present with symptoms similar to a common cold; and given the high levels of virus replication observed in these patients, it wouldn’t be unreasonable to assume that they can easily transmit the virus.  This is serious as it means that based on government advice – which specifies persistent cough and raised temperature – most people who can potentially transmit will not be aware the risk they pose to others and will not self-isolate.  This needs careful consideration by those charged with mitigating the impact of this pandemic.”


Dr Nathalie MacDermott, NIHR Academic Clinical Lecturer, King’s College London, said:

“While the number of daily new cases of COVID-19 in the UK continues to climb this is not unexpected as there is now person to person transmission of the virus within the UK.  As we are currently still in the season when coughs and cold and flu like symptoms are common it will be difficult for people to differentiate whether their initial symptoms are from COVID-19 or another virus.  This is why the UK government mentioned several possibilities that could be introduced during the ‘delay’ stage to reduce the spread of COVID-19, these include closing schools for a period of time, postponing large scale public gatherings and asking anyone with cold and flu like symptoms to remain at home for 7 days.  Today the government announced that they are requesting members of the public who have a new onset, continuous cough or fever (>37.8C) to remain at home for 7 days to try and reduce the spread of the virus in the UK.  It is essential that we all take responsibility for our actions and honour the request of the government in this matter, not just to protect those we care about, but also the vulnerable in our society.  We all have a role to play in trying to bring the UK epidemic under control.

“While all the measures the government mentioned for the delay phase are important in limiting spread of the virus, evidence indicates if such measures are brought in too early then the population become fatigued with complying with them over time.  Hence the government’s decision to introduce them in stages with appropriate scientific evidence indicating they will significantly affect the course of the UK epidemic at that stage.  The importance of community engagement and population compliance with public health measures in containing disease outbreaks should not be under-estimated.  It is therefore a fine balance of when to introduce such measures and achieving this balance is clearly of prime importance to both the UK government and Chief Medical Officer.”


Prof Keith Neal, Emeritus Professor in the Epidemiology of Infectious Diseases, University of Nottingham, said:

“The plans are sensible, it is very easy to say more needs to be done, but there is little evidence to make any decision.  If people who might have coronavirus (or another virus) self isolate based on fever and cough then this should limit the spread of the virus.  What we know is that people are most infectious during the first week of symptoms.

“Italy’s lock down is not the lockdown used in Wuhan – people are still going out and mixing.  We need to follow what happens to inform our decision making for the next week or two.  It will be interesting to see how long the Italian population will accept the limited lockdown, they may have to do so for many months and people will get tired and not cooperate, enforcement will not be possible as in China and Singapore.

“Cancelling school trips and cruises for the over 70s will have virtually no impact on the functioning of society.

“My comments about school closure still stand. (see

“At sporting events you are in close prolonged contact with 8 people – those around you, and three of these are behind you which will be difficult to infect.  If you close the sporting ground people may go and watch in a pub or with friends – more significant close contact might occur.  If those with fever and cough don’t go the risk markedly reduced.  Even with 10,000 people in a crowd the probability that anyone is infected in the crowd currently is very very low.  Older people and those at increased risk may be advised to avoid crowds of any sort.

“Cases will keep increasing for a number of months, it is the nature of an epidemic.”


Prof Sheila Bird, Formerly Programme Leader, MRC Biostatistics Unit, University of Cambridge, said:

“How the UK intends to monitor the future evolution of COVID-19 cases is changing: the shift to focus testing on hospitalized patients is sensible and means that UK’s monitoring is to be mainly in respect of more serious COVID-19 cases – those hospitalized on account of COVID-19 or for other reasons but found to be positive for COVID-19.

“Hence, UK’s future monitoring of COVID-19 cases will not be on the same basis as hitherto.

“Today’s pragmatic shift to hospitalized-testing signals that the UK will monitor carefully and efficiently more serious manifestations of COVID-19.  This approach directs our testing capability at monitoring the very cases that cause most concern because they have required hospitalization; and which tell us how the serious manifestations of coronavirus evolve over the next 8 to 16 weeks.  Hence, UK will be tracking a different doubling-time than hitherto – not all cases (mild COVID-19 cases will no longer be tested) but primarily hospitalized COVID-19 cases.

“We should anticipate a further shift in the age-distribution of COVID-19 cases: from the age-distributions for nearly 600 cases up to 12th March 2020 (who include those with milder symptoms) to the age-distribution thereafter (predominantly for hospitalized COVID-19 cases).”


Prof Jimmy Whitworth, Professor of International Public Health, London School of Hygiene & Tropical Medicine, said:

“This is a balanced and measured response.  They have clearly come to a different strategy to some other European countries about what to do.

“The strategy clearly is going to be flexible and to adapt over time as the circumstances change.

“Based on evidence from other countries the most realistic approach to this is to initiate the strongest public health measures that will be supported by the general British public.

“I am surprised that stronger measures haven’t been introduced at this stage but I anticipate that they will come in the next week or two.

“The longer we delay in introducing social distancing measures, the harder it is for these to be effective at delaying the outbreak.  But at the same time, measures that are introduced will need to be in place for a substantial time in order to be effective.  So it is important that the public accept the measures and don’t tire of their engagement too early.”


Dr Michael Head, Senior Research Fellow in Global Health, University of Southampton, said:

“Our existing knowledge suggests that social distancing is effective in delaying and reducing the peak of the outbreak.  However, these interventions require significant compliance from the general population over an extended period of time, otherwise fatigue can set in among the general public.  The peak of the outbreak is estimated to be 10-12 weeks away.  The impact of closing sporting events or stopping flights is of limited impact in reducing and delaying transmission.  Therefore, the Chief Medical Officer has highlighted the importance of the timing when implementing any large-scale shutdown and encouraged the support of the general population, particularly around protecting the most vulnerable members of society.”


All our previous output on this subject can be seen at this weblink:

The SMC also produced a Factsheet on COVID-19 which is available here:


Declared interests

None received.

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