Coronavirus (COVID-19): Scotland's testing strategy - adapting to the pandemic

Section Three - Priorities - Who We Test

Testing Priorities – Next Phase

1. Whole Population Testing of anyone with symptoms (Test & Protect).

2. Proactive Case Finding by testing contacts and testing in outbreaks.

3. Protecting the vulnerable and preventing outbreaks in high risk settings by routine testing.

4. Testing for direct patient care, to diagnose and to treat, and to support safe patient care as NHS services restart.

5. Surveillance to understand the disease, track prevalence, understand transmission and monitor key sectors.

Whole Population Testing of Anyone with Symptoms

Our first priority is testing people with symptoms, and the preparation of sufficient capacity to test increasing numbers of people with non-specific symptoms, which may or may not be COVID, in autumn and winter.

Building and enhancing our public awareness campaign on COVID-19 symptoms and how to book a test is one element of this work. Improving access to testing for people – in particular in the community – is the other element. This includes simplification of routes to booking a test, better sign-posting of non-digital routes to testing and better access to testing for those who do not have a car.

Proactive Case Finding by Testing Contacts and Testing In Outbreaks

Our second priority is proactive case finding by testing close contacts and testing in outbreaks. Advice from our COVID-19 Expert Advisory Group indicates proactive case finding - hunting for the virus - through selected asymptomatic testing has high levels of potential benefit for the strategic aim of suppressing transmission to the lowest levels possible.

The highest level of benefit in terms of reducing transmission will be from identifying those most likely to have been infected. The highest level of benefit in terms of reducing harm will be from detecting asymptomatic positive cases who may transmit to high risk individuals in high risk settings.

At this point in time in the pandemic, those most likely to have been infected include contacts of index cases who have been traced. Once established as PCR-positive, a contact would become a new index case allowing a new range of contacts to be identified and the prevention, and earlier ending, of transmission chains.

The European Centre for Disease Control suggested in its recent June update that testing strategies could extend to testing asymptomatic contacts if resources allow, in order to find new cases, allow for onward tracing of their contacts sooner, and break transmission chains. Given the successful expansion of capacity to both undertake PCR testing (swabbing capacity) and process the results (laboratory capacity), resource does now allow for this, and Scotland will now move to offering testing all close contacts of index cases.

As the pandemic progresses over the next phase, the expected pattern of transmission is of local outbreaks and clusters of cases. Testing will be a key tool as part of the overall public health management response to outbreaks.

When an outbreak has or is suspected to have occurred, local health protection teams will use testing to identify further cases among those who are linked to the outbreak, as part of the wider incident management arrangements.

The rapid deployment of Mobile Testing Units in response to outbreaks will support swift testing (followed by contact tracing and isolation of contacts) as part of the public health response to minimising the outbreak and its potential to contribute to wider community transmission.

Protecting the Vulnerable and Preventing Outbreaks in High Risk Settings by Routine Testing

The third current priority is protecting the vulnerable and preventing outbreaks in higher risk settings – which we know from experience and from evidence includes healthcare and social care settings.

In addition to these settings having experienced transmission rates that were generally higher than the community, they can also contain large numbers of people who are elderly, frail and in poor health, putting them at increased risk should they become infected. While the primary public health interventions for reducing the risk of transmission in health and social care settings are appropriate infection prevention and control (IPC) measures including physical distancing and PPE, there may also be a role for testing in these settings as part of a package of response.

In social care settings, our current policy is to minimise the risk of new cases of COVID-19 entering a care home setting by testing all people discharged to care homes from hospital and all those entering care homes from the community, both symptomatic and asymptomatic. In addition, in recognition of the risk of care home staff introducing the virus to a care home, possibly when asymptomatic or presymptomatic, weekly testing of all care home staff was introduced from 25th May.

When a care home finds a suspected case of COVID-19, the local health protection team initiates an investigation which includes testing all residents and staff. Where care homes are part of a group of homes, given the potential for staff to work between different care homes of the same provider, testing is also conducted in link homes.

The final part of our current testing policy in care home settings is to regularly test a sample of care homes where there is no current infection for surveillance purposes and to better identify, as early as possible, any potential new outbreaks.

In hospitals, current policy is that all asymptomatic healthcare staff are tested where there is an outbreak in a previously COVID free ward. From early July, this was extended to include weekly testing of healthcare staff working in specialist oncology wards, long term care of the elderly wards, and long term care wards in mental health facilities.

Testing for Direct Patient Care, To Diagnose and To Treat, and To Support Safe Patient Care as NHS Services Restart

Our fourth current priority is testing for direct patient care. This testing supports diagnosis and therefore guides appropriate patient care for those presenting with potential COVID symptoms. Since the start of the pandemic, ICU patients and all symptomatic patients admitted to hospital have been tested, both to ensure they receive the necessary care and to protect against onward transmission.

As the NHS remobilises as we cautiously move through the Routemap, more patients who do not have symptoms will be tested prior to receiving healthcare, particularly in circumstances where treatment would be deferred if they tested positive, for example, those undergoing elective surgery or treatments which involve immunosuppression.

Surveillance to Understand the Disease, Track Prevalence, Understand Transmission and Monitor Key Sectors

Our fifth priority is significantly expanding surveillance testing - both at a whole population level and in key sectors. This is to monitor prevalence of the disease, better understand transmission and support our journey through the Routemap.

Community surveillance testing includes PCR testing of people who have mild or moderate illness to help us understand levels of active disease, and antibody testing to improve our understanding of how many people have been infected with the virus.

Public Health Scotland (PHS) is leading the Enhanced Surveillance of COVID-19 in Scotland (ESoCiS) programme on behalf of Scottish Government which encompasses this PCR and antibody testing, in addition to other surveillance measures.

In a significant expansion of population level surveillance testing, Scotland will also participate in the ONS COVID-19 Infection Survey, which will represent the single biggest expansion of asymptomatic testing for surveillance purposes to date in the pandemic, building to 15,000 individuals tested every two week rolling period. This equates to approximately 9,000 households.

The survey will involve all participants providing throat and nose swabs to test whether they currently have the virus. A subset of the sample will also provide blood samples, which will be tested for antibodies to COVID-19. Individuals will be asked to take tests every week for the first five weeks and monthly for a period of 12 months in total. Each participant is also asked a short set of questions concerning socio-demographic characteristics, symptoms, whether self-isolating or shielding, and whether the participant has come into contact with a suspected carrier of COVID-19.

Critically, the information from the study will be linked to the Community Health Index (CHI) enabling future linking to other health datasets in Scotland and further analysis. Given much is yet to be understood about the long term health impacts of COVID-19 on those who have recovered from infection, and how these impacts vary by different groups of people, this data linkage will be critical in providing evidence in these poorly understood areas which will directly support the effective long term management of those who may still suffer from post COVID related health harms.

In healthcare, Scotland is participating in the SIREN study which seeks to understand whether the presence of COVID-19 antibodies protects people from future infection and also to provide evidence of prevalence of COVID infection among healthcare workers across Scotland.

In a significant expansion of healthcare worker surveillance testing, the aim is to recruit 10,000 NHS workers in Scotland to the study, covering all health boards. Each healthcare worker will be PCR and antibody tested every 2 weeks over a 12 month period. This will help our understanding of the body's immune response to COVID-19 and track prevalence rates within that population.

In schools, in addition to the testing of individuals with symptoms and increased testing that takes place in the context of an outbreak, we will implement testing of a sample of the school population for the purposes of surveillance. This testing as part of our surveillance approach will play an important role in supporting the safe return and ongoing safe operation of our schools.

Testing for surveillance will involve a sample of the school population being tested for COVID-19 and for SARS-CoV-2 antibodies at intervals to determine if they have evidence of current or past infection.

These surveillance studies will include school worker testing and surveys, and school pupil cohort surveillance, which will provide data that can be used for providing incidence and prevalence estimates to understand any level of infection or exposure in schools. Any positive tests found would be further tested for whole genome sequencing to understand where any transmission may have occurred.