Coronavirus (COVID-19): framework for decision making

Section 3: Preparing for Transition

• We must suppress transmission of the virus (R<1.0).
• We must continue to adhere to the advice: stay at home if symptomatic; keep physically distanced; and maintain good hand hygiene and cough hygiene.
• We must develop the public-health capability to deal with cases and outbreaks in a way that prevents widespread community transmission.

Scotland, with the other three UK nations, entered lockdown on 23^rd March 2020. Under law, we are committed to reviewing that lockdown at least every three weeks. This ensures the impact of restrictions remains proportionate to the threat posed and that limitations, such as those on our freedom to travel and gather together, do not remain in place any longer than is necessary. On 16^th April, all the restrictions and requirements under the Health Protection (Coronavirus) (Restrictions) (Scotland) Regulations 2020 were reviewed.

The regulations contain restrictions on movement and physical distancing and requirements on businesses to close premises. Following the review, based on advice from the Chief Medical Officer in Scotland and informed by broader evidence of economic and societal impacts, a decision was made that all current restrictions and requirements continue to be necessary to protect public health, in accordance with the requirements for the review process set out in the regulations.

In common with nations across the world, Scotland is planning for a managed transition away from current restrictions in a way that enables the suppression of transmission to continue. This will include ongoing physical distancing, the continued need for good hand hygiene and public hygiene, and enhanced public health surveillance - while seeking to very carefully open up parts of our economy and society.

As and when we lift restrictions, we will need to put in place public health measures to stop cases becoming clusters, clusters becoming outbreaks, and outbreaks becoming an uncontrolled peak that would require a return to lockdown to avoid enormous loss of life and the overwhelming of our health and care system.

Expanding public health services will not be sufficient to deal with the virus in future– although it is vital that we do so. We will require to take other measures to control transmission.

As a result of the current lockdown, there are early signs the virus has been slowed – but it has not been eradicated. We will need people in Scotland to continue to live their lives in ways that minimise the spread of the virus. So even as we lift some of the more restrictive measures, better hand hygiene and appropriate physical distancing will need to remain in place, at home, on the streets and in the workplace.

With the lockdown measures currently in place we are seeing early signs that the impact of the virus is being contained. By complying with these restrictions people have protected our NHS and saved lives.

The Scottish Government publishes on a daily basis: the number of new cases; number of hospitalisations; numbers requiring ICU care; and new deaths related to the virus. In recent days, there are signs that the rate of growth in new cases has slowed. This slowing has only been made possible by the actions of the public in adhering to physical distancing measures.

The chart below shows the impact of the lockdown. Before lockdown, cases would double around every 4 days. Cases now take over two weeks to double. This means far fewer people have become infected than otherwise: the actions we have all taken have saved lives.

The single most important measure to help us understand how fast the virus is spreading and the degree to which it is under control is the "reproduction number" or "R"^[2]. The reproduction number is a measure of the contagiousness or transmissibility of a virus – in other words, the number of cases each infected person passes the virus on to. To contain the virus we must keep the R number below 1, and this means minimising the risk of spreading the virus at every turn. When R is over 1, exponential growth returns.

Our best estimate is that due to restrictive measures the reproduction number could now be between 0.6 and 1.0. This has only been achieved because so many workers are working from home, in general less than 1% of children are attending the emergency provision in schools and other settings, levels of use of public transport have fallen to more than 90% below usual levels, and very high numbers of people are sticking to the physical distancing best practice. We know too that the sum is greater than the parts – the combination of measures is more effective at reducing R than individual measures. It is also important to note that the reproduction number will be higher in specific settings like care homes.

That does not leave us much scope to ease restrictions. Even very small increases in the reproduction number will have large impacts on transmission and can lead to a significant peak in hospitalisations and death. The World Health Organisation has stated that before any decision is made to lift restrictions, transmission of COVID-19 must be controlled. That means that we must see R stabilise below 1.0 and ensure that the impact of any decision to ease restrictions must maintain R below 1.0.

And bringing down the number of new cases per day matters too. Lowering the number of new cases per day as much as possible, together with an R below 1, will mean fewer cases and reduced harm.

We will continue to gather the data we need to assess progress of the virus. This includes community enhanced surveillance through testing integrated into the work of our community hubs treating COVID-19 and the telephone COVID triage service. We are also working alongside the other UK nations to develop serological (antibody) testing which will allow us, if and when available, to assess the extent of immunity in the population.

We need to be confident that community transmission is under control before we consider changes to the current restrictions. The advice from our advisers on the best estimates for Scotland of the reproduction number will be a critical component of our decision making. As part of this, we will continue to monitor – and publish – daily numbers of cases, of people in hospital, and of people in ICU. We will need to see sustained evidence that on these measures the spread of the virus is slowing down.