Releasing Britons from lockdown in two batches is the best exit strategy

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Releasing Britons from lockdown in two batches is the best exit strategy to reduce deaths and and protect the economy, scientists claim.

Researchers led by University of Oxford said half the population should be released four months before the rest because everyone at once is ‘too risky’.

The team suggest young people, who are less likely to get severely sick with Covid-19, come out of lockdown first and go back to work immediately. 

They predict a second wave would strike six weeks later but after this older people — known to be more vulnerable to severe Covid-19 — could emerge from lockdown.  

Number 10 could closely monitor what happens in the initial phase before deciding if it was safe for the vulnerable to be released, the team said.

Experts did not explain exactly who would form part of each group, only suggesting that young people should be the first. Other scientists have also thrown out the idea of letting younger and less vulnerable people back into society first. 

It comes as Prime Minister Boris Johnson considers the next steps out of lockdown, with beer gardens thought to be allowed to reopen in a fortnight. 

Concerns have been raised that lockdown is crippling the economy and threatening some 3.5million job losses in the hospitality sector.

The move, which would be brought forward from July 4, is a fine balance between protecting the livelihoods of Britain and avoiding Covid-19 deaths. 

Getting young people back to work first before allowing the elderly out of lockdown four months later is the best exit strategy, an Oxford study says

Some scientists have proposed easing the draconian restrictions by age, allowing younger people back out to kick-start the economy.

Downing Street’s strategy to come out of lockdown is based on three phases which apply to the whole population.  

The first phase, triggered on May 13, allowed people in England to go outdoors as much as they wanted.

The second, on June 1, saw schools and some shops re-opening and a slight expansion of social circles.

The third, no earlier than July 4, will allow some hospitality venues such as pubs to welcome the public.  

The Oxford-led team compared a staggered release of people from lockdown with another strategy called ‘on-off’, using the UK as a model.

An ‘on-off’ strategy is when everyone is released from lockdown, but it is slapped back on when infections become too high.  

Their calculations, published in the journal Frontiers in Public Health, was based on an equation: Susceptible, Exposed, Infectious, and Recovered. 

Everyone falls into one of those groups — they have either not had the coronavirus, currently have it, or have recovered (or died).

Scientists can model how many people would be in each group for two different scenarios – but did not publish the figures.

They based their model on a set of assumptions on the attack rate of the virus – how quickly it spreads between people.  

The NHS can only cope when 4million people are infected at any given time — the equivalent of six per cent of the population, the team said. 

This is based on the fact the NHS has just over 9,240 ICU beds, and around a third of those hospitalised with Covid-19 (4.4 per cent of people infected) may need critical care, according to separate models from Imperial College London.

Lead author and graduate Thom Rawson said releasing the whole population from lockdown at once would overwhelm the NHS – which experts feared would happen in this first wave. 

They found it would not be possible to end lockdown for the entire population for any longer than two weeks as ‘the number of infected individuals would rise dramatically in a short period of time’. 

To protect the NHS, the optimal strategy would be the staggered approach. 

The Oxford team suggest young people, who are less likely to get severely sick with Covid-19, come out of lockdown first and go back to work immediately. Pictured: People at Bournemouth beach on May 29 after the first lockdown exit phase was implemented

The Oxford team suggest young people, who are less likely to get severely sick with Covid-19, come out of lockdown first and go back to work immediately. Pictured: People at Bournemouth beach on May 29 after the first lockdown exit phase was implemented 

The researchers predict a 'likely second wave' of infections one or two months after the first release date because the virus would still be circulating. Pictured: People at Durdle Door, May 30

The researchers predict a ‘likely second wave’ of infections one or two months after the first release date because the virus would still be circulating. Pictured: People at Durdle Door, May 30

IS A SECOND WAVE INEVITABLE? 

Almost all scientists agree the infection is bound to re-emerge in a second wave in the absence of a vaccine or cure for the coronavirus. 

Dr Andrea Ammon, the EU’s boss on disease control, has warned the virus is not going away any time soon because it is ‘very well adapted to humans’.

She has urged Europe to prepare for another crisis, which she said was inevitable because so few people will have developed COVID-19 immunity. 

In an interview with The Guardian on May 21 she said: ‘The question is when and how big, that is the question in my view.’

Dr Hans Kluge, director for the WHO European region, said he was ‘very concerned’ a surge in infections would coincide with other seasonal diseases such as the flu.  

Speaking exclusively to The Telegraph in mid-May, he cautioned that now is the time for ‘preparation, not celebration’ across Europe – even if countries are show positive signs of recovery.

Professor Hugh Pennington, an emeritus microbiologist at University of Aberdeen, has said there is no evidence there will be a second wave of the coronavirus, contradictory to the thoughts of others.

Scientists have repeatedly referred to the 1918 Spanish flu pandemic as a sign the world is heading towards a devastating relapse in cases. But the flu is biologically completely different from the coronavirus and should not be comparable, Professor Pennington said.

But he added: ‘If we get the easing of lockdown wrong, far more likely would be a continuation of infections, many in the form of localised outbreaks, but not waves or peaks.’

Writing in The Daily Telegraph , he said Covid-19 tends to cause clusters of cases, which bodes well for the future. 

Professor Mark Woolhouse, of Edinburgh University, said it is more likely the UK will experience small outbreaks because the R rate of the coronavirus has been squased.

At its peak, the reproduction – or R – R number was between two and three, which meant every infected person passed the virus on to two or three others. It is now between 0.7 and 0.9, putting it below the crucial level of one, which is when cases spiral out of control.

Professor Woolhouse, who is part of the Government’s Scientific Advisory Group for Emergencies (Sage), told The i: ‘Am I concerned that the R number might creep above one? Yes I am. But am I concerned it will go back to where we were at the beginning of the first wave, no I’m not.

‘There is no prospect whatsoever that it’s going to go up to two or three again that’s far, far from the reality of what we might reasonably expect. I’m not so much concerned about a second wave, I’m concerned about a second bump.

‘The only way that a second wave could happen is if there were a complete collapse in lockdown and everybody just gave up on it despite what the Government said – and that’s just not going to happen.’

The R number has been guiding Government on when to lift lockdown. But the K number will become crucial for fighting a potential second wave, scientists believe.

The K number tracks the extent to which new outbreaks are caused by a few ‘superspreading events’, The Sunday Times reports. 

The London School of Hygiene and Tropical Medicine conducted a study which suggests the majority of secondary transmission may be caused by ‘super spreaders’ – a very small fraction of individuals. In other words, 10 per cent of people are highly infectious, and lead to 80 per cent of transmission. 

The other 90 per cent of individuals don’t actually spread it to many other people. They are responsible for the remaining 20 per cent of Covid-19 transmission.

Adam Kucharski, an associate professor at LSHTM who was involved with the research, said: ‘If a handful of events generate most of your outbreak, then if you can find a way of identifying where and when those events are happening then that reduces far more of your transmission than if you were just trying to follow up every case as if they were the same.’ 

It would involve releasing approximately half the population two to four weeks from the end of the outbreak ‘peaking’. 

Figures suggest the UK’s peak was April 7, when 4,477 laboratory cases were recorded – the highest number in one day.

The academics explained a two-week period would be crucial to ensure new daily cases are very low — but they did not give a figure for how low, and the UK was still recording 3,000 cases a day two weeks after its peak. 

Two months after the peak, around 5,500 people in the UK are still becoming infected each day, according to government surveillance testing, of which the majority do not show in government figures. 

The first group of people could return to work while maintaining social distancing as much as possible, with the knowledge that there is a chance they will get Covid-19.

While the model itself does not say who exactly should be released from lockdown first, the authors suggest that this should be the young. 

The young are less likely to get severely sick with Covid-19 should they be infected. Therefore there would be less deaths and people needing hospital care. 

It may also bolster herd immunity — when the majority of a population have already been exposed to an infection, causing the virus to die out.   

The researchers predict a ‘likely second wave’ of infections one or two months after the first release date because the virus would still be circulating. 

Once again, a crucial wait period will be needed to ensure cases are very low again before everyone else could be released four months later.  

The researchers said: ‘By ensuring the increase in the number of infected individuals is as slow as possible, this will enable health officials to monitor more accurately the evolving situation.

‘[It would] provide more time to respond to unexpected increases in the number of infected individuals.’

The other benefit of gradual release would be avoiding a potentially devastating second wave in which large numbers of elderly and vulnerable people get the virus and die.

However, they did not discuss in depth whether a third wave would occur once the second group are in society again.

The authors wrote: ‘We find that ending quarantine for the entire population simultaneously is a high-risk strategy, and that a gradual re-integration approach would be more reliable.’

The team said lockdown shouldn’t be ended in any manner until new daily confirmed cases ‘reaches a sufficiently low threshold’. They did not say what this would be. 

The first people out of lockdown would need to be monitored very closely in order to see how the virus spreads again.

It would require a very efficient testing strategy because it’s impossible to know how much of the population is infected without mass testing.

First author Dr Thomas Rawson from the University of Oxford said: ‘The delayed incubation period between infection and presenting symptoms means that we are constantly seeing the effect of the disease a few days late. 

‘Only by ramping up testing measures can we accurately get a sense of how the spread and control of disease is happening. This will allow us to respond quickly if an unmanageable second wave begins to appear.

‘The take-home message for decision-makers is to act very cautiously, and to monitor any lockdown release very closely. 

‘Our model shows that second waves can occur very quickly if transmission rates end up higher than expected, or if more people relax their lockdown measures than expected.’  

The model can only make mathematical guesses for what could happen. In reality, people’s behaviour can produce a completely different result. 

‘Exactly what happens as lockdown eases can be hard to predict, as different people will respond in different ways,’ said lead author Professor Michael Bonsall, University of Oxford.

‘However, when a large enough group of people is considered, mathematical models like ours are able to represent the expected average behaviors across a large population.

‘Ongoing testing is then important to check that any disease increase does not surpass the predicted bounds.’

The lockdown has shaped people’s lives for the past three months, but ministers recognise it needs to end in order to save the economy.

A vaccine is still several months away, potentially years if current clinical trials fail, but the lockdown – with millions out of work and children out of school – cannot stay in place forever. 

The Government published their roadmap out of lockdown – involving three phases – in a 50-page document last month. 

A second peak which overwhelms the NHS is considered the ‘biggest threat to life’ in the UK, according to the ‘roadmap’. 

To avoid a second deadly wave, the Government plans to use contact tracing, whereby anyone who has been close to a confirmed COVID-19 case is tested or isolated.    

The second consideration is protecting and restoring people’s livelihoods by getting people back to work safely as soon as possible.