covid-19 antibody survey of education staff (cass) report 1 · other 415 2.1% unknown 245 ; 1.2% ....

A Management Information release for Scotland

COVID-19 Antibody Survey of education Staff (CASS) Report 1

Publication date: 16 December 2020

Public Health Scotland

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This is a Management Information publication Published management information are non-official statistics which may be in the process of

being transitioned into official statistics. They may not comply with the UK Statistics

Authority’s Code of Practice with regard to high data quality or high public value, but there is

a public interest or a specific interest by a specialist user group in accessing these statistics

as there are no associated official statistics available.

Users should therefore be aware of the aspects of data quality and caveats surrounding

these data, all of which are listed in this document.

Find out more about Management Information publications at:

www.statisticsauthority.gov.uk/wp-content/uploads/2016/06/National-Statisticians-Guidance-

Management-Information-and-Official-Statistics.pdf

http://www.statisticsauthority.gov.uk/wp-content/uploads/2016/06/National-Statisticians-Guidance-Management-Information-and-Official-Statistics.pdfhttp://www.statisticsauthority.gov.uk/wp-content/uploads/2016/06/National-Statisticians-Guidance-Management-Information-and-Official-Statistics.pdf


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Contents Introduction .............................................................................................................................. 3

Main points ............................................................................................................................... 4

Methods ................................................................................................................................... 5

Results and commentary ......................................................................................................... 7

Glossary ................................................................................................................................. 20

Contact ................................................................................................................................... 21

Further information ................................................................................................................. 21

Rate this publication ............................................................................................................... 21

Appendix 1 – Data tables ....................................................................................................... 22

Appendix 2 – Publication metadata ........................................................................................ 29

Appendix 3 – Early access details ......................................................................................... 30

Appendix 4 – PHS and Official Statistics................................................................................ 31


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Introduction In March 2020, as part of coronavirus (COVID-19) control measures, schools in Scotland

were closed to almost all pupils. Since mid-August they have re-opened full-time to all pupils

with infection prevention measures in place.

As part of its work to better understand how COVID-19 is affecting people in Scotland, Public

Health Scotland (PHS) leads the COVID-19 education surveillance programme.1 One

element of this programme is the COVID-19 Antibody Survey of education Staff (CASS),

launched in October 2020.

COVID-19 is a disease caused by the new coronavirus known as SARS-CoV-2

(‘coronavirus’). When the body is infected with coronavirus, it produces antibodies to help

fight it. Some of these specific antibodies remain in the blood after the body recovers, and

they can be detected by blood tests known as serology tests. Using such blood tests, CASS

aims to monitor the proportion of people working in education in Scotland who have

coronavirus antibodies, and how this changes over the school year 2020/21.

CASS is voluntary and open to any adult who works in a school or an early learning and

childcare setting in Scotland. Participation involves completing a monthly online survey and a

monthly home-based antibody blood test managed by the UK Government antibody testing

programme.2

In this report, we report the first findings of CASS covering blood samples taken in the period

from 17 October 2020 to 16 November 2020.

1 More information about the components of PHS Public Health Education Surveillance Programme

can be found at: www.hps.scot.nhs.uk/a-to-z-of-topics/enhanced-surveillance-of-coronavirus-covid-

19/enhanced-surveillance-for-education/

2 Details of the UK Government antibody testing programme can be found at:

www.gov.uk/government/publications/coronaviruscovid-19-testing-privacy-information/antibody-

testing-for-coronavirus-privacyinformation

http://www.hps.scot.nhs.uk/a-to-z-of-topics/enhanced-surveillance-of-coronavirus-covid-19/enhanced-surveillance-for-education/http://www.hps.scot.nhs.uk/a-to-z-of-topics/enhanced-surveillance-of-coronavirus-covid-19/enhanced-surveillance-for-education/http://www.gov.uk/government/publications/coronaviruscovid-19-testing-privacy-information/antibody-testing-for-coronavirus-privacyinformationhttp://www.gov.uk/government/publications/coronaviruscovid-19-testing-privacy-information/antibody-testing-for-coronavirus-privacyinformation


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Main points This report provides summary results of nearly 20,000 participants in the COVID-19 Antibody

Survey of education Staff (CASS) in Scotland, who had blood samples taken between

17 October and 16 November 2020.

• The proportion of participants who had antibodies detected is estimated to be 7.3%

(95% confidence interval (CI) 6.9%–7.7%). This is an adjusted figure, which takes into

account the performance of the test in detecting antibodies.

• There were no significant differences between men and women, or by age group, in

the proportion of participants that had antibodies detected. Participants of non-White

ethnicities had a higher estimated seroprevalence (11.2% (95% CI 7.2%–17.1%)),

than those of White ethinicities (7.3% (95% CI 6.9%–7.7%)). However, it should be

noted that this estimate for non-White ethnicities is based on a small sample.

• The proportion of staff working in secondary-school settings that had antibodies

detected (6.3% (95% CI 5.7%–6.9%)) was slightly lower than staff in early learning

and childcare (8.2% (95% CI 7.2%–9.4%)) and primary-school settings (7.7% (95% CI

7.1%–8.3%)).

• Among staff groups, a slightly higher proportion of wider education workforce had

antibodies detected (8.8% (95% CI 7.6%–10.1%)) than teaching and teaching support

staff (7.1% (95% CI 6.6%–7.6%)). There was no difference between teaching and

teaching support staff, and early learning and childcare staff.

• In four local authority areas (based on location of workplace), the proportion of

participants that had antibodies detected was higher than the overall national estimate.

These were Inverclyde, Glasgow City, Renfrewshire and North Lanarkshire. In seven

local authority areas, the proportion of participants that had antibodies detected was

lower than the national estimate.

No direct comparison data are available; however, these results show that the proportion of

education staff who had antibodies in this period is similar to the proportion of the general

adult population in Scotland estimated to have antibodies. This is based on the data from the

ONS Infection survey of a random sample of households, which estimates that 7.1% and


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7.3% of the Scottish adult population would have antibodies in October and November,

respectively.

Methods Participant recruitment and testing CASS is open to any adult member of staff working in a school or early learning and

childcare setting in Scotland. Participation is completely voluntary. Participants are recruited

using invitation packs distributed through national and local authority stakeholders, and they

self-enrol online. After agreeing to participate, participants complete an online survey and

register with the UK Government antibody testing service.

Registrants with the UK testing service who meet inclusion criteria for working in an

education setting, based on industry and occupation, are invited to receive a test kit by post.

Using this test kit, participants collect a small finger-prick blood sample that is returned to the

UK Government antibody testing service for analysis. The specific antibody test used during

this period was the Elecsys® Anti-SARS-CoV-2 immunoassay (Roche®).

Details of recruitment material and participant journey can be found at: www.hps.scot.nhs.uk/web-resources-container/cass-participant-information/

Details of the UK Government antibody testing service can be found at: www.gov.uk/government/publications/coronaviruscovid-19-testing-privacy-information/antibody-

testing-for-coronavirus-privacyinformation

Period of analysis This report reviews the findings from samples taken during the period from 17 October 2020

to 16 November 2020. Schools in all areas of Scotland were open from 18 August (with the

majority of areas open from 12 August). There was the planned October break of one or two

weeks in all areas. Specific dates for this varied, but in all areas it fell in the period from 5 to

19 October.

http://www.hps.scot.nhs.uk/web-resources-container/cass-participant-information/http://www.gov.uk/government/publications/coronaviruscovid-19-testing-privacy-information/antibody-testing-for-coronavirus-privacyinformationhttp://www.gov.uk/government/publications/coronaviruscovid-19-testing-privacy-information/antibody-testing-for-coronavirus-privacyinformation


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Data sources The data for CASS come from the online questionnaires participants complete before their

antibody test and the results of the antibody test. Participants’ responses to the online

questionnaire are matched to the antibody tests using community health index (CHI) linkage.

CHI number is a unique health record identifier used in patient records in Scotland.

Outcomes This report presents the proportion of people who had antibodies to the coronavirus, also

known as seroprevalence, by age, sex, ethnicity, socioeconomic deprivation and

occupational characteristics. These proportions are adjusted for the performance of the tests,

and a 95% CI is provided for each.3, 4

Information governance A COVID-19 Rapid Data Protection Impact Assessment (DPIA) was completed for this

programme, with approval obtained from the PHS Data Protection Officer.

3 Public Health England. Evaluation of Roche Elecsys Anti-SARS-CoV-2 serology assay for the

detection of anti-SARS-CoV-2 antibodies. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/891598/Evalu

ation_of_Roche_Elecsys_anti_SARS_CoV_2_PHE_200610_v8.1_FINAL.pdf

4 According to the PHE Porton Down Lab methodology, this reports uses the specificity of 100% (95%

confidence interval (CI) 99.1–100%) and sensitivity of 86.1% (95% CI 76.5–92.8%) at ≥14 days of

symptoms when adjusting estimates for the performance of the blood test.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/891598/Evaluation_of_Roche_Elecsys_anti_SARS_CoV_2_PHE_200610_v8.1_FINAL.pdfhttps://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/891598/Evaluation_of_Roche_Elecsys_anti_SARS_CoV_2_PHE_200610_v8.1_FINAL.pdf


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Results and commentary Participant characteristics The data reported in this first report refer to 19,653 participants for whom data from both the

questionnaire and an antibody test result were available for the period covering 17 October

and 16 November 2020.

The majority of the participants were female (88.9%) and of White ethnicity (98.9%). The

median age was 41 years (interquartile range 33 to 50 years). More than half the participants

(55.2%) resided in areas which are in the two least deprived quintiles, according to the

Scottish Index of Multiple Deprivation (SIMD).

In terms of work setting, 44.8% worked in primary schools, 32.5% worked in secondary

schools, and 15.3% in early learning and childcare settings. The majority of participants were

either teachers or teaching support staff professionals (74.1%). Other participants had a

range of roles in the wider education workforce, and they included cleaning, catering, admin

and janitorial staff. The workplace settings of participants covered all 32 local authorities in

Scotland.

A detailed breakdown of participant characteristics is provided in Table 1. Information on the

local authority of participants’ place of work can be found in Figure 1 and Table A1 in

Appendix 1.

When interpreting the results of this report, it is important to consider how well the

participants in CASS represent the overall education workforce in Scotland. A number of

factors may have influenced who participated in the survey. These include the effectiveness

of dissemination of information about CASS in reaching all staff groups and locations, and

potential barriers to participation, such as needing internet and mobile phone access. It is

also possible that people’s feelings about coronavirus in general, and/or their assessment of

whether they may have previously had COVID-19, influenced whether they took part in

CASS. Table A2 in Appendix 1 provides a comparison of CASS participants to available data

on the characteristics of the educational workforce in Scotland.


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Table 1: Demographic characteristics of 19,653 participants included in this report

Characteristic Number Proportion or range

Sex Female 17,468 88.9%

Male 2,176 11.1% Prefer not to say 9 0.01%

Age in years Median age and interquartile range2 41 33 to 50

16-39 8,791 44.7% 40+ 10,862 55.3%

Ethnicity All White 19,435 98.9%

White British 18,836 95.8% White non-British 599 3.0%

Caribbean / Black 5 0.0%3 Asian, Asian Scottish or Asian British 83 0.4%

Other 99 0.5% Prefer not to say 31 0.2%

Socioeconomic deprivation based on area of residence4 1 (Most deprived) 1,858 9.5%

2 3,039 15.5% 3 3,909 19.9% 4 5,145 26.2%

5 (Least deprived) 5,702 29.0% Workplace setting

Early Learning and Childcare 3,016 15.3% Primary School 8,814 44.8%

Secondary School 6,382 32.5% Special School 781 4.0%

Other 415 2.1% Unknown 245 1.2%

Job role Early Learning and Childcare staff 2,537 12.9%

Teacher 11,059 56.3% Head Teacher 652 3.3%

Additional Support Needs teacher 460 2.3% Teaching support staff 2,394 12.2%

Admin and Library staff 795 4.0% Catering staff 283 1.4% Cleaning staff 119 0.6%

Other staff 1,106 5.6% Not known 248 1.3%


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1. Exact figure: 0.05% 2. Interquartile range gives an indication of where the majority of values lie 3. Exact figure: 0.03% 4. Socioeconomic deprivation is measured using Scottish Index of Multiple Deprivation version 2020.


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Figure 1: Map of number of participants by local authority of workplace1, 2

1. Participants came from workplaces located in all 32 local authorities in Scotland. 2. Detailed breakdown of participants per local authority of workplace can be found in Table A1

in Appendix 1.


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Proportion of participants testing positive for antibodies to coronavirus Overall, an estimated 7.32% (95% CI 6.93%–7.72%) of participants had SARS-CoV-2

antibodies. In this section, we report these proportions by personal, occupational and

workplace characteristics.

The results reported in this section have been adjusted to take into account the performance

of the laboratory tests in detecting antibodies.5 For comparison, the unadjusted estimate for

the proportion of CASS participants with antibodies was 6.30% (95% CI 5.97%–6.65%). Full

data for unadjusted values can be found in Table A3 of Appendix 1.

Analyses by sex, age and ethnicity

The proportion testing positive was not significantly different between males and females

(7.85% for males and 7.25% for females). Similarly, proportions did not significantly differ

between age groups (7.19% in the age group 16–39 years and 7.42% in the 40+ years age

group).

Ethnicity data was available for 99.8% of the participants. Overall, 11.18% of participants with

non-White ethnicity had antibodies detected (95% CI from 7.17%–17.07%), compared with

7.29 of those with White ethnicity (95% CI from 6.90%–7.70%). However it should be noted

that this estimate for non-White ethnicities is based on a small sample of fewer than 200

individuals.

Figure 2 below summarises proportion of participants testing positive for antibodies to

coronavirus by sex, age and ethnicity. Full details of the confidence intervals are reported in

Table A4 of Appendix 1.

5. Diggle PJ, 2011. Estimating prevalence using an imperfect test. Epidemiology Research

International, 2011.


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Figure 2: Proportion of participants testing positive for antibodies to coronavirus by sex, age and ethnicity1, 2

1. Seroprevalence reports the proportion of individuals testing positive for antibodies to coronavirus.

2. Values reported here were adjusted for test accuracy using Bayesian methods described in Diggle PJ, 2011. Estimating prevalence using an imperfect test. Epidemiology Research International, 2011.

Analyses by workplace setting and job role

Workplace setting data was available for 98.8% of participants. Participants working in

secondary schools had a slightly lower proportion of antibody positivity (6.26% (95% CI

5.65%–6.94%)) than those working in primary schools (7.67% (95% CI 7.09%–8.29%)) and

early learning and childcare (8.24% (95% CI 7.24%–9.37%)).

Job role data was available for 98.7% of participants. Participants in the wider education

workforce had a higher antibody positivity (8.78% (95% CI 7.60%–10.11%)) than those in

teaching and teaching support roles (7.08% (95% CI 6.64%–7.55%)).

Figure 3 below shows results by work setting and job role. Full details of the confidence

intervals are reported in Table A4 of Appendix 1.


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Figure 3: Proportion of participants testing positive for antibodies to coronavirus by workplace setting and job role1, 2


2. Values reported here were adjusted for test accuracy using Bayesian methods described in Diggle PJ, 2011. Estimating prevalence using an imperfect test. Epidemiology Research International, 2011.

Analyses by deprivation index

The analysis by deprivation index is based the Scottish Index of Multiple Deprivation (SIMD)

quintiles for the area in which participants live. This data was available for all participants.

Among those living in areas in the most deprived quintile 8.63% had antibodies detected

(95% CI 7.34%–10.12%), compared to 7.33% in the least deprived quintile (95% CI 6.63%–

8.10%).

Figure 4 below shows the breakdown of proportion of antibody positivity by SIMD. Full details

of the confidence intervals are reported in Table A4 of Appendix 1.


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Figure 4: Proportion of participants testing positive for antibodies to coronavirus by socioeconomic deprivation1, 2


2. Values reported here were adjusted for test accuracy using Bayesian methods described in Diggle, P.J., 2011. Estimating prevalence using an imperfect test. Epidemiology Research International, 2011.

Analyses by local authority of workplace

The analysis by local authority is based on the area of workplace of participants, and data on

the proportion of antibody positivity was available for 92.9% of participants.

In four local authority areas the proportion of participants with antibodies detected was higher

than the overall national estimate of 7.32%, based on the full CASS sample. There were

Inverclyde (18.6%, 95% CI 14.15%–24.11%), Glasgow City (10.39%, 95% CI 8.95%–

12.02%), Renfrewshire (9.79%, 95% CI 7.51%–12.68%), and North Lanarkshire (9.44%, 95%

CI 7.75%–11.46%). The estimate for Inverclyde is based upon a relatively small sample of

fewer than 300 participants.

Participants working in Aberdeenshire, Angus, Dumfries and Galloway, Highland, Moray,

Perth and Kinross, and the Scottish Borders had a lower proportion with antibodies detected

than the overall national estimate.


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Figure 5 below shows the breakdown of proportion of antibody positivity by local authority of

workplace. Full details of the confidence intervals are reported in Table A5 of Appendix 1.


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Figure 5: Proportion of participants testing positive for antibodies to coronavirus by local authority of workplace1, 2

1. Seroprevalence reports the proportion of individuals testing positive for antibodies to coronavirus. Values reported here were adjusted for test accuracy using Bayesian methods described in Diggle PJ, 2011. Estimating prevalence using an imperfect test. Epidemiology Research International, 2011.

2. The horizontal blue line shows the overall national proportion (7.32%) calculated from CASS. 95% confidence interval around this estimate was 6.93 to 7.72.


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Discussion This report presents initial results from the first month of CASS. These findings contribute to

our understanding of the extent to which people in the education workforce in Scotland has

had coronavirus in the past.

Overall, the CASS results indicate that the proportion of education staff who had antibodies

to coronavirus was 7.3% (95% CI 6.9%–7.7%) in the period from mid-October to mid-

November 2020. This result is consistent with estimates of the proportion of the general adult

population in Scotland who had antibodies in this period from the Office for National Statistics

(ONS) COVID-19 Infection Survey. This ONS survey tests individuals in a sample of

households to estimate the proportion of the population that would test positive for

antibodies. It therefore provides the best available comparison data. For October 2020, the

ONS survey estimated that 7.1% of the population in Scotland aged over 16 years would

have tested positive (95% CI 4.6%–10.4%) and 7.3% in November (95% CI 5.9%–10.8%).6

No direct comparison of CASS findings with other occupational groups is currently possible,

as this survey method has only been applied in Scotland. However, the ONS Survey provides

estimates for England by occupational group; in October 2020 it was estimated that 8.1% of

those working in the education sector would have tested positive for antibodies (95% CI

5.9%–10.8%).6

The main results presented are based on estimates of seroprevalence that have been

adjusted to take account of how accurate the test is in identifying antibodies, using

established methods which have also been used by Public Health England and the PHS

Serology Workstream.7 The Public Health England laboratory estimate of the sensitivity of

the test used in CASS (the probability that it will give a positive result when the subject being

6www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/articles/coronavir

uscovid19infectionsinthecommunityinengland/december2020#likelihood-of-testing-positive-for-covid-19-

antibodies-in-england-wales-northern-ireland-and-scotland

1. Diggle PJ, 2011. Estimating prevalence using an imperfect test. Epidemiology Research

International, 2011.

http://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/articles/coronaviruscovid19infectionsinthecommunityinengland/december2020#likelihood-of-testing-positive-for-covid-19-antibodies-in-england-wales-northern-ireland-and-scotlandhttp://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/articles/coronaviruscovid19infectionsinthecommunityinengland/december2020#likelihood-of-testing-positive-for-covid-19-antibodies-in-england-wales-northern-ireland-and-scotlandhttp://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/articles/coronaviruscovid19infectionsinthecommunityinengland/december2020#likelihood-of-testing-positive-for-covid-19-antibodies-in-england-wales-northern-ireland-and-scotland


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tested actually has antibodies) is 86.1% at 14 or more days after the onset of COVID-19

symptoms. The adjustment generates an estimate of what the seroprevalence would be if the

test were 100% accurate, therefore the adjusted estimates for CASS are higher than the

unadjusted estimates. The unadjusted estimates simply reflect the proportion of CASS

participants who had a positive antibody test. It is not yet known how long antibodies remain

detectable following coronavirus infection.

Several differences in antibody positivity by job role and workplace setting were observed in

CASS, though these were small and of uncertain meaning in public health terms. The

estimated proportion of participants with non-White ethnicities with antibodies to coronavirus

is based on a relatively small sample and has a wide confidence interval. This means that

although the higher point estimate for these participants compared with White participants

may reflect a true difference between population groups, the data suggest it could also be the

result of chance.

The CASS findings showed considerable variation in antibody positivity by local authority of

the workplace. Broadly, this was consistent what we would expect based on the geographical

differences in coronavirus infection rates in the general population. The highest rates of

positive antibody tests were seen in Inverclyde, Glasgow City, Renfrewshire and North

Lanarkshire, all of which are local authorities in the west of the central belt in Scotland that

has seen relatively high occurrence of COVID-19 across the two waves of the pandemic.

Antibodies may be present as a result of infection at any point in the coronavirus pandemic,

so infection rates in both the first and second wave may have a bearing on results.

The CASS sample is large, with nearly 20,000 participants in the first month of analysis. It is,

however, not fully representative of the whole education workforce. Table A2 provides some

information to help assess representativeness, though it is limited by the availability of data

on the characteristics of the populations of education staff, and in some circumstances

indicative figures are used which are not directly comparable. The majority of CASS

participants were teachers, with other staff groups very likely to be under-represented in

comparison. Women were more likely than men to participate, and it is also possible that

some ethnic groups are under-represented. CASS participants were more likely to live in

relatively affluent deprivation quintiles. This distribution is especially marked for teachers,


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although in the absence of comparison data it is not possible to ascertain if this is because of

the socio-economic status of teachers in general, or because of bias in the CASS sample.

Furthermore, CASS is based on open recruitment, with anyone within the eligible population

able to volunteer and take part. This means that differences in how information about the

study reached different geographical and occupational groups may have introduced bias into

the cohort. For example, sharing of information through social media may have resulted in

people who use particular forms of social media or belong to specific groups being more

likely to participate. Similarly, individual motivations for taking part may also have influenced

the findings, for example if people who were more anxious about coronavirus, or who thought

they had already had COVID-19, were more likely to sign up.

It is important to note that the current results are based on the description of findings in single

groups, and do not take account of factors which may overlap, such as the interaction

between job role and social and demographic factors. Future, more detailed, analyses will be

able to adjust for some of these factors to some extent and provide further insight into the

factors associated with having antibodies detected. Further rounds of data from CASS will

also permit monitoring over time, providing information on if and how the proportion of

education staff with antibodies to coronavirus changes through the 2020/21 school year.


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Glossary Antibodies: Specific proteins produced by the body when fighting infections.

CHI: Community Health Index, an administrative unique identification used in health records in Scotland.

COVID-19: The disease caused by the new strain of coronavirus known as SARS-CoV-2.

Prevalence: The proportion of individuals in a population that have a disease (or positive test) over a specific time.

SARS-CoV-2: Severe Acute Respiratory Syndrome Coronavirus 2, the new strain of coronavirus that causes COVID-19.

Serology: A blood test carried out in a component of blood known as serum.

Seroprevalence: The proportion of individuals who tested positive for antibodies against a specific infection among all those tested. In this report, it is used as an estimate of how many

people have been infected by coronavirus in the population.


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Contact Dr Diane Stockton Email: [email protected]

Dr Lynda Fenton Consultant in Public Health Medicine Phone: 0141 201 4726

Email: [email protected]

For all media enquiries please email [email protected] or call 07500 854574.

Further information Further information and data for this publication are available from the publication page on

our website.

Rate this publication Let us know what you think about this publication via the link at the bottom of this publication

page on the PHS website.

mailto:[email protected]:[email protected]:[email protected]


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Appendix 1 – Data tables Table A1: Number of participants per local authority

Local authority Total Proportion (%) Aberdeen City 607 3.09 Aberdeenshire 826 4.20 Angus 530 2.70 Argyll and Bute 323 1.64 City of Edinburgh 1,564 7.96 Clackmannanshire 233 1.19 Dumfries and Galloway 580 2.95 Dundee City 519 2.64 East Ayrshire 464 2.36 East Dunbartonshire 492 2.50 East Lothian 427 2.17 East Renfrewshire 482 2.45 Falkirk 666 3.39 Fife 1,208 6.15 Glasgow City 1,789 9.10 Highland 642 3.27 Inverclyde 281 1.43 Midlothian 441 2.24 Moray 358 1.82 Na h-Eileanan Siar 37 0.19 North Ayrshire 450 2.29 North Lanarkshire 1,132 5.76 Orkney Islands 48 0.24 Perth and Kinross 627 3.19 Renfrewshire 605 3.08 Scottish Borders 299 1.52 Shetland Islands 118 0.60 South Ayrshire 417 2.12 South Lanarkshire 1,387 7.06 Stirling 411 2.09 West Dunbartonshire 442 2.25 West Lothian 1,068 5.43 Unknown 180 0.92 Total 19,653 100.00


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Table A2: Comparison of participants to the background population

Characteristic CASS teachers / head teachers

National comparison for teachers

CASS support staff

Support staff comparison

CASS ELC staff

Comparison for ELC staff

CASS wider education workforce

Overall numbers 12,171 Approx. 52,000 2,394 - 2,537 2,303

Sex Male 15.6% Approx. 23% 2.7% - 1.4% Approx. 2% 6.4%

Female 84.4% Approx. 77% 97.3% - 98.6% Approx. 98% 93.6% Age in years

Average age = 40 years

16-39 51.0% 22.9% - 53.2% - 27.4%

40+ 49.0% 77.1% - 46.8% - 72.6% Ethnicity

White British 95.3% Approx. 89% 97.0% - 96.3% - 97.0% White non-British 3.5% Approx. 3% 2.0% - 2.6% - 2.4%

Asian, Asian Scottish or Asian British 0.5% Minority

ethnic group approx 1-2%

0.5% - 0.5% - *

Caribbean or Black * * - * - * Other 0.6% 0.3% - 0.4% - 0.3%

Workplace setting Early Learning and

Childcare 0.7% Approx. 2% 2.7% - 88.6% - 25.8%

Primary School 50.5% Approx. 49% 62.4% Approx. 63% 8.3% - 37.4% Secondary School 43.4% Approx. 46% 20.4% Approx. 22% * - 22.3%

Special School 3.6% Approx. 4% 10.4% Approx. 15% 0.7% - 2.3% Other 0.8% - 1.8% - 1.1% - 10.2%

Unknown 0.9% - 2.3% - 1.1% - 2.0% SIMD quintile

1 (Most deprived) 6.6% - 13.7% - 14.8% - 14.8% 2 13.1% - 18.5% - 21.2% - 18.7% 3 19.0% - 19.8% - 22.5% - 21.6% 4 28.1% - 24.1% - 22.3% - 22.4%

5 (Least deprived) 33.2% - 23.8% - 19.3% - 22.5%

Comparisons for teachers from www.gov.scot/publications/teacher-census-supplementary-statistics/

(2019; unlike CASS data does not include Head Teachers); comparisons for support staff from

www.gov.scot/publications/school-support-staff-statistics/ (2019, based on FTE and not head count);

comparisons for ELC staff from https://data.sssc.uk.com/data-publications/228-the-children-s-

services-workforce-2018 (2018. No comparison data were available for the wider education

workforce. Note that approximate figures are indicative only and are estimates based on published

http://www.gov.scot/publications/school-support-staff-statistics/https://data.sssc.uk.com/data-publications/228-the-children-s-services-workforce-2018https://data.sssc.uk.com/data-publications/228-the-children-s-services-workforce-2018


24

data where comparison groups do not directly match CASS data. * Indicates that data are not

presented for disclosure reasons. Prefer not to say and missing responses not shown.


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Table A3: Unadjusted proportion of individuals testing positive for antibodies to coronavirus by personal and occupational characteristics1, 2

Characteristic Proportion (%) Lower limit for 95% confidence interval

Upper limit for 95% confidence interval

Overall 6.30 5.97 6.65 Sex

Male 6.25 5.90 6.61 Female 6.76 5.78 7.89

Prefer not to say * * * Age in years

16-39 6.19 5.70 6.71 40+ 6.39 5.94 6.86

Ethnicity White 6.28 5.94 6.63

Non-White 9.63 6.18 14.70 Prefer not to say * * *

Socioeconomic deprivation 1 (Most deprived) 7.43 6.32 8.71

2 6.75 5.91 7.69 3 5.65 4.97 6.42 4 6.10 5.48 6.79

5 (Least deprived) 6.31 5.71 6.97 Workplace setting

Early Learning and Childcare 7.10 6.23 8.07 Primary School 6.60 6.10 7.14

Secondary School 5.39 4.86 5.97 Special School 6.79 5.23 8.77

Other 5.30 3.53 7.90 Unknown 9.39 6.34 13.69

Job role Teaching and support staff 6.10 5.72 6.50

Early learning and childcare staff 6.46 5.57 7.49 Wider education workforce 7.56 6.55 8.71

Unknown 4.84 2.79 8.27 Local authority

Aberdeen City 6.75 5.02 9.04 Aberdeenshire 2.42 1.57 3.71

Angus 3.40 2.16 5.30 Argyll and Bute * * *

City of Edinburgh 6.39 5.29 7.72 Clackmannanshire 8.15 5.28 12.38

Dumfries and Galloway 3.45 2.24 5.27 Dundee City 6.74 4.89 9.23

East Ayrshire 4.31 2.81 6.56


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Characteristic Proportion (%) Lower limit for 95% confidence interval


East Dunbartonshire 7.93 5.85 10.65 East Lothian 5.39 3.62 7.95

East Renfrewshire 7.26 5.27 9.93 Falkirk 7.66 5.87 9.93

Fife 5.88 4.69 7.35 Glasgow City 8.94 7.71 10.36

Highland 3.89 2.65 5.69 Inverclyde 16.01 12.19 20.76 Midlothian 6.58 4.62 9.28

Moray 3.07 1.72 5.42 Na h-Eileanan Siar * * *

North Ayrshire 5.56 3.79 8.07 North Lanarkshire 8.13 6.67 9.86

Orkney Islands * * * Perth and Kinross 3.35 2.20 5.07

Renfrewshire 8.43 6.47 10.91 Scottish Borders 3.34 1.83 6.05 Shetland Islands * * *

South Ayrshire 4.80 3.13 7.29 South Lanarkshire 7.21 5.96 8.69

Stirling 6.81 4.76 9.67 West Dunbartonshire 7.92 5.75 10.81

West Lothian 7.02 5.64 8.71 Unknown 6.11 3.45 10.61

5. These values are not adjusted for the accuracy of the test and differ from the adjusted figures. 6. Values for some characteristics are suppressed (shown as * in the table) to preserve participant

confidentiality.


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Table A4: Proportion of individuals testing positive for antibodies to coronavirus by personal and occupational characteristics1

Characteristic Proportion (%) 95% Confidence Interval

Overall 7.32 6.93 to 7.72 Sex

Male 7.85 6.71 to 9.16 Female 7.25 6.85 to 7.68

Prefer not to say 0.00 0.00 to 34.74 Age in years

16-39 7.19 6.62 to 7.79 40+ 7.42 6.90 to 7.97

Ethnicity White 7.29 6.90 to 7.70

non-White 11.18 7.17 to 17.07 Not known 0.00 0.00 to 12.81

Socioeconomic deprivation based on area of residence 1 (Most deprived) 8.63 7.34 to 10.12

2 7.83 6.86 to 8.94 3 6.57 5.77 to 7.46 4 7.09 6.37 to 7.89

5 (Least deprived) 7.33 6.63 to 8.10 Workplace setting

Early Learning and Childcare 8.24 7.24 to 9.37 Primary School 7.67 7.09 to 8.29

Secondary School 6.26 5.65 to 6.94 Special School 7.88 6.07 to 10.19

Other 6.16 4.10 to 9.17 Unknown 10.90 7.36 to 15.90

Job role Teaching and support staff 7.08 6.64 to 7.55

Early learning and childcare staff 7.51 6.47 to 8.70 Wider education workforce 8.78 7.60 to 10.11

Unknown 5.62 3.24 to 9.60 1. Values reported here were adjusted for test accuracy using Bayesian methods described in

Diggle PJ, 2011. Estimating prevalence using an imperfect test. Epidemiology Research International, 2011.


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Table A5: Proportion of individuals testing positive for antibodies to coronavirus per local authority of workplace1, 2

Local authority Proportion (%) Lower limit for 95% confidence interval


Aberdeen City 7.84 5.83 10.49 Aberdeenshire 2.81 1.83 4.31

Angus 3.94 2.51 6.16 Argyll and Bute * * *

City of Edinburgh 7.43 6.14 8.96 Clackmannanshire 9.47 6.14 14.38

Dumfries and Galloway 4.00 2.61 6.12 Dundee City 7.83 5.68 10.73

East Ayrshire 5.01 3.26 7.62 East Dunbartonshire 9.21 6.80 12.37

East Lothian 6.26 4.20 9.24 East Renfrewshire 8.43 6.12 11.53

Falkirk 8.89 6.82 11.53 Fife 6.83 5.44 8.54

Glasgow City 10.39 8.95 12.03 Highland 4.52 3.08 6.60

Inverclyde 18.60 14.16 24.11 Midlothian 7.64 5.36 10.78

Moray 3.57 2.00 6.29 Na h-Eileanan Siar * * *

North Ayrshire 6.45 4.40 9.38 North Lanarkshire 9.44 7.75 11.46

Orkney Islands * * * Perth and Kinross 3.89 2.56 5.88

Renfrewshire 9.79 7.51 12.68 Scottish Borders 3.88 2.12 7.02 Shetland Islands * * *

South Ayrshire 5.57 3.63 8.47 South Lanarkshire 8.37 6.93 10.10

Stirling 7.91 5.52 11.23 West Dunbartonshire 9.20 6.68 12.56

West Lothian 8.16 6.55 10.12 Unknown 7.10 4.00 12.32

1. Values reported here were adjusted for test accuracy using Bayesian methods described in Diggle PJ, 2011. Estimating prevalence using an imperfect test. Epidemiology Research International, 2011. Values for some local authorities suppressed (shown as * in the table) since these authorities had fewer than 5 positive tests of antibodies to coronavirus. This was done according to the Public Health Scotland statistical disclosure protocol to preserve participant confidentiality.


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Appendix 2 – Publication metadata Metadata Indicator Description

Publication title COVID-19 Antibody Survey in education Staff (CASS) Description Descriptive results of the

Theme Enhanced surveillance Topic Seroprevalence, COVID-19, Education

Format Text, tables and charts data Data source(s) CASS, Antibody testing data

Date that data are acquired October-November 2020 Release date 16/12/2020

Frequency As appropriate Timeframe of data and

timeliness COVID-19 antibody serology tests date 17 October 2020 to 16 November 2020

Continuity of data N/A Revisions statement N/A

Revisions relevant to this publication

N/A

Concepts and definitions See methodology and glossary. Relevance and key uses of

the statistics Pandemic management: Communicable disease control

Accuracy Completeness Comparability This is the first presentation of these data in Scotland.

Accessibility Public Health Scotland follows published guidelines to make publications accessible.

Coherence and clarity Value type and unit of

measurement Percentage of tests that are positive.

Disclosure Statistical disclosure controlled applied according to Public Health Scotland Disclosure Protocol.

Official Statistics designation Management Information Release UK Statistics Authority

Assessment N/A

Last published 16 December 2020 Next published TBC

Date of first publication 16 December 2020 Help email

Date form completed 10 December 2020


30

Appendix 3 – Early access details Pre-Release Access Under terms of the ‘Pre-Release Access to Official Statistics (Scotland) Order 2008’, PHS is

obliged to publish information on those receiving Pre-Release Access (‘Pre-Release Access’

refers to statistics in their final form prior to publication). The standard maximum Pre-Release

Access is five working days. Shown below are details of those receiving standard Pre-

Release Access.

Standard Pre-Release Access • Scottish Government Health Department

• NHS Board Chief Executives

• NHS Board Communication leads

Early Access for Management Information These statistics will also have been made available to those who needed access to

‘management information’, for example as part of the delivery of health and care:

• Scottish Government Education Department

• Directors of Public Health

Early Access for Quality Assurance These statistics will also have been made available to those who needed access to help

quality assure the publication:

• Katie Allison, COVID Public Health Directorate: Health and Social Care Analysis Hub,

Scottish Government

• Rebekah Carton, Antibody & Surveillance Testing Team Leader, Scottish Government


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Appendix 4 – PHS and Official Statistics About Public Health Scotland (PHS) PHS is a knowledge-based and intelligence-driven organisation with a critical reliance on

data and information to enable it to be an independent voice for the public’s health, leading

collaboratively and effectively across the Scottish public health system, accountable at local

and national levels, and providing leadership and focus for achieving better health and

wellbeing outcomes for the population. Our statistics comply with the Code of Practice for

Statistics in terms of trustworthiness, high quality and public value. This also means that we

keep data secure at all stages, through collection, processing, analysis and output

production, and adhere to the ‘five safes’.

https://www.statisticsauthority.gov.uk/code-of-practice/the-code/https://www.statisticsauthority.gov.uk/code-of-practice/the-code/https://blog.ons.gov.uk/2017/01/27/the-five-safes-data-privacy-at-ons/

Report 1Publication date: 16 December 2020Participant recruitment and testingPeriod of analysisData sourcesOutcomes Information governance Participant characteristicsProportion of participants testing positive for antibodies to coronavirus Analyses by sex, age and ethnicityAnalyses by workplace setting and job roleAnalyses by deprivation index Analyses by local authority of workplace

Discussion Pre-Release AccessStandard Pre-Release AccessEarly Access for Management InformationEarly Access for Quality AssuranceAbout Public Health Scotland (PHS)

covid-19 antibody survey of education staff (cass) report 1 · other 415 2.1% unknown 245 ; 1.2% ....

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