Research carried out exclusively for Sky News suggests 'social distancing' could slow the spread of coronavirus in the UK - and reduce the peak number of cases by up to a half.

Health officials want to avoid large numbers of people in hospital at the same time - as the UK moves into a "delay" phase of tackling the outbreak rather than just trying to "contain" it.

And one of the strategies they are looking at is 'social distancing', which means reducing people's physical contact.

Moderate examples include working from home and cancelling large sporting events and concerts, as well as school closures.

More extreme ones could be quarantining towns or stopping public transport, like what happened in China's Hubei province - the epicentre of the outbreak.


This is how an epidemic of a virus similar to COVID-19 can look like in a single county in the UK without any social distancing measure. If we start adopting moderate social distance measures and keep them for four weeks… …the outbreak would slow down and the peak delayed until the summer, reducing it by 25%. But if we keep the measures for eight weeks instead... ...the peak could be reduced by half - avoiding an acute pressure on the NHS and tailing off before autumn. And if we made the social distancing measures more strict... ...it would suppress the epidemic even more until… … the measures are lifted and the peak will be pushed to the autumn and winter, coinciding with the flu season. Let’s put all the model together to draw some conclusions. Social distance can have a positive effect when trying to slow down an epidemic and reduce the number of peak cases. A longer period is more beneficial. This could alleviate pressure on the health services, but will have an impact on other sectors like the economy. But these measures cannot be indefinite, and there is a risk of delaying the epidemic to winter when the NHS is under more strain.

So how effective could such measures be as the government tries to cut down on person-to-person transmissions?

Lancaster University has carried out modelling which suggests whether officials take a moderate or extreme approach could be crucial as could be the timing.

Academics estimated how the epidemic might spread without any social distancing measure and then modelled the potential impact of three different scenarios on a county in the UK.

The first scenario - a moderate approach which aimed to reduce the spread by 30% over a four-week period - suggested the peak could be cut by 25% and delayed to the summer.

A second scenario took a similar approach but this time over a longer, eight-week period. It could reduce the peak by 50% - avoiding an acute pressure on the NHS and tailing off before autumn.

Image: The number of coronavirus cases in the UK is rising

Finally academics looked at a more extreme approach like China's quarantining of Hubei province. This aimed to reduce the spread by 60% over eight weeks.

While initially effective, once the measures were lifted, the model suggested a second wave of cases and a higher peak to coincide with the start of the winter flu season, when traditionally the NHS is under more pressure.

How to contain a global pandemic

This research explains why some experts worry that cases will rise in China when restrictions on Hubei are lifted.

For Public Health England, moderate measures are probably better and they need optimal time to have an impact.

Methodology:

This is an SEIR model developed by Jessica Bridgen, PhD student at Lancaster University. The model shows an epidemic of an infectious disease with the current best estimated characteristics of Covid-19 in a single county of the UK, with a population size of approximately 1.1 million, and starting with 100 people infected. The model assumes a R0 of 2.2, an average latent period of 5 days (similar to the incubation period) and an average infectious period of 5 days.



Why not plot the y-axis? The model illustrates how social distancing as an intervention could affect the number of cases during an epidemic, but it is not a predictive tool. To avoid misunderstanding, we have decided not to show the total number of cases predicted by the model, but instead how social distancing can shift the dynamics of an epidemic.