Office for National Statistics COVID-19 Infection Survey
As part of Scotland’s Covid-19 testing strategy, Scotland is participating in the Office for National Statistics (ONS) COVID-19 Infection Survey. The first estimates of the percentage of people in Scotland who test positive for COVID-19 were published today, 23 October. The Scottish results are published on the gov.scot website, and on the ONS website alongside results for England, Wales and Northern Ireland.
What is the Covid infection survey?
The COVID-19 Infection Survey aims to find:
- how many people test positive for COVID-19 infection at a given point in time, either with or without symptoms
- the average number of new infections per week over the course of the study
- the number of people who test positive for antibodies, to indicate how many people may have already had COVID-19
The survey is building up to testing 15,000 individuals per fortnight. By carrying out mass testing regardless of whether participants have COVID-19 symptoms or not, the survey will help track the current extent of infection and transmission of COVID-19. As well as looking at the number of positive cases, the survey will be used to examine the characteristics of those testing positive for COVID-19, and the symptoms that they may experience.
The results from the survey will be used in many different ways in order to inform the response to the pandemic. After reaching the target of 15,000 individuals tested per fortnight, the sample size for this survey will be large enough to allow for regional analysis to provide a more local picture of how the virus is affecting Scotland.
Carrying out the survey
The survey is being conducted by the Office for National Statistics (ONS) and the University of Oxford, on behalf of the UK and Scottish Government. The survey also operates in England, Wales and Northern Ireland.
Survey teams started to visit participant households in Scotland on Monday 21st September. Invitations were sent to randomly sampled private households across Scotland. Participants provide self-administered throat and nose swabs to test whether they currently have the virus. A subset of the total number of participants (20%) are also invited to provide blood samples, which will be tested for the presence of COVID-19 antibodies. Blood samples are only taken from individuals aged 16 and above and will be taken by a trained nurse, phlebotomist or healthcare assistant.
Participants are asked to repeat this survey over either a month or 12 months. This involves:
- a visit once a week from a member of the survey team to collect a throat and nose swab. This will happen for 4 weeks in a row, after the first visit.
- a visit once a month after this, for 11 months in a row, to collect a throat and nose swab. If providing a blood sample, participants will be asked to provide a blood sample every month after the first appointment.
Each participant is also be asked a short set of questions about socio-demographic characteristics, symptoms, whether they are self-isolating or shielding, and if they have come into contact with a suspected carrier of COVID-19.
Only private households are included in the survey, meaning that people in care homes, other communal establishments and hospitals are not included.
Due to response rates being higher than initially expected, the first results for the percentage of the population testing positive for COVID-19 were made available for Scotland on 23 October. Scottish results for the survey will be published weekly, and will be available on gov.scot as well as on the Office for National Statistics website, where they are published alongside results for England, Wales and Northern Ireland.
As the sample size is increased in subsequent weeks, more detailed analysis such as such as examining the characteristics of those testing positive for COVID-19, establishing the average number of new infections per week, and the number of people who test positive for antibodies to indicate how many people are ever likely to have had the infection will follow.
If you’ve been invited to take part in the survey you can find out more on the ONS website.
Information on the survey methodology can be found here.