A two-week circuit-breaker in December could save thousands of lives in the short-term, government advisers have said.
Scientists said it may be too late to implement a two-week circuit-breaker over the October school half-term but December could be an option to allow the UK breathing space to control the epidemic.
One of the advisers, Graham Medley, a member of the government's Scientific Advisory Group for Emergencies (Sage), said that a short, sharp lockdown would enable Test and Trace to improve and ensure the NHS does not become overwhelmed.
He told a webinar any circuit-breaker should ideally be timed with school holidays "half-term or potentially over Christmas" to minimise disruption to education.
Other experts warned that circuit breakers may keep having to be imposed until a vaccine is found, that a circuit breaker by by itself would not quash the R number (the rate of infection) stricter measures would be needed too, and that if R is not brought back below one a second lockdown is inevitable.
“You could even potentially add a week to the Christmas school holidays and potentially get some kind of three-week break, but the whole point is to reduce the prevalence before you actually have to do it," Professor Medley said.
“The reason that the lockdown (in March) worked, is because it separated households.
“And that’s essentially what we’ve got to do is to make sure that the transmission doesn’t go from household to household, and two weeks is the minimum time.”
He said regular circuit-breakers that were implemented regardless of case and hospital numbers would give people warning and could have long-term benefits.
“We’re going to have to go into severe measures at some point, so why don’t we do it before we absolutely have to?,” Prof Medley said.
“Why don’t we do it for two weeks or three weeks, before we absolutely have to, and then that means that we avoid an emergency break?
“There are two advantages of that – one is for sure which is that it reduces the load on the NHS.
“And the other one potentially is… a known break, a known lockdown, is better than an unknown lockdown.
“My understanding is that in terms of mental health – and for businesses – it’s much better if you know it’s going be for two weeks, and you know when it’s going to start.”
However, Prof Medley said that it may now be too late for an October half-term lockdown, "but if you said the first two weeks of December, then… staff can take holidays, businesses can work around that and potentially people can say ‘right, I’m going to go and stay with my sister for two weeks’.
“You won’t be able to leave once you got there, but you could actually make it, I think, quite liveable.”
Prof Medley said thousands of deaths could be prevented up to January with a circuit-breaker but that did not necessarily translate into lives saved in the long term.
The modelling paper written by Prof Medley and colleagues sets out that deaths could possibly reduce for the rest of the year from about 19,900 to 12,100. Hospital admissions could be reduced from 132,400 to 66,500.
A limited lockdown, with schools and shops open but hospitality venues closed, could potentially cut deaths to about 15,600, they said.
Prof Medley said the figures contained in the research paper were in effect a worst-case scenario for "illustrative purposes" looking at what would happen with no interventions.
According to a new poll, the majority of the public back a circuit-breaker lockdown over the October half-term.
YouGov asked more than 3,390 adults in Great Britain on Wednesday whether they would support or oppose two weeks of tough restrictions later this month.
Some 68% of respondents said they would support the measure, compared to 20% who said they would oppose them, while 12% said they did not know.
However, Prof Medley said the “stronger you can go in and control it for two weeks, the better the impact, the bigger reduction you can get".
He added: “People have said this is kicking the can down the road, and it is – you’re not saving lives.
“What you’re doing is delaying the next wave until after January, so yes it does look as though you’re preventing deaths in that time period, but it just means that you’ve delayed (them).”
However, he said lives would undoubtedly be saved through the NHS not becoming overloaded and by the health service being able to continue with other routine care, such as cancer treatments.
Another expert on the webinar suggested that circuit breaker lockdowns may keep having to be imposed regularly to keep coronavirus under control until a vaccine is found.
"Without some magic vaccine or cure we are facing a very, very long road on this and so we are always pushing things forward," Prof Matt Keeling of the University of Warwick said.
“If we don’t have a vaccine or some other form of therapeutic treatment then most people are going to catch this disease or a high proportion of the population will. "
"So almost any measure, unless it in some way completely restructures our population, is always going to be pushing things further down the road.
“But we are thinking that hopefully there will be a vaccine at some point in the future, so it is thinking more about how we push things forward in time.”
He told a webinar that multiple, regular circuit-breaker lockdowns might be necessary as we learn to live with Covid-19, adding: “But if we can plan them sufficiently well in advance we can hopefully mitigate the worst impact they will have.”
However, the webinar also heard warnings that a circuit-breaker lockdown will not reduce the R rate of transmission by itself.
“This only gives us a chance to rewind, it doesn’t reduce what R is going forward – we do need to think about getting control measures in place as well as thinking about circuit breakings," Prof Keeling said.
He said the circuit-breaker idea had been suggested at a recent Sage meeting as “one of a whole raft of measures to be considered”.
On Monday, Prime Minister Boris Johnson introduced a three-tier system of coronavirus measures for England, but Prof Medley said there was “mixed evidence” that this would work, and that there was a “danger” that places in Tier Three may not be able to step back down to Tier Two if measures were not strong enough.
Scientists suggested test and trace could be one of the things that could be ramped up during a circuit-breaker as the number of coronavirus cases fell.
“At the moment, we’re very close to capacity on what test and trace can do so if there’s more capacity in the system, there’s more potential for pushing things down, and it’s easier to investigate little outbreaks that occur,” he said.
“If we end up with too many cases, then PHE (Public Health England) is going to be overwhelmed by the number of outbreaks that will occur.
“So being at low levels means you have the opportunity to keep sort of stamping on any little outbreak that you see.
“It’s also advantageous in that it takes us back – in the best case – it takes us back to some time in August, so we have that sort of extra month of planning… (during which) we could think about alternative control measures.”
Northern Ireland is set for a four-week period of intensified coronavirus restrictions that will see the closures of schools, pubs and restaurants.
It came days after Sage published a report revealing that a national circuit-breaker lockdown was at the top of their shortlist of coronavirus interventions last month.