Investigating the prevalence of long COVID in Scotland

Previously published estimates of long COVID prevalence

Office for National Statistics (ONS) COVID-19 Infection Survey (CIS)

The Office for National Statistics (ONS) published estimates of prevalence of ongoing symptoms of COVID-19 for Scotland covering the period March 2021 to March 2023. Estimates were produced using data from the ONS Coronavirus (COVID-19) Infection Survey (CIS) which ran until March 2023. Participants who knew or thought they had COVID-19 were asked if they would describe themselves as having long COVID, defined as experiencing symptoms more than four weeks after a COVID-19 infection that are not explained by something else.

These estimates show 79,000 (1.5% of people living in private households) in Scotland had self-reported long COVID in the four weeks to 6 March 2021. This increased to 204,000 (3.9%) in the four weeks to 3 September 2022, before decreasing to 172,000 (3.3%) in the four weeks to 5 March 2023. However, due to changes in data collection mode from face-to-face interview to online, estimates up to July 2022 are not directly comparable with estimates from after this time (see the methodology section).

Participants were asked whether long COVID reduced their ability to carry out day-to-day activities compared with the time before having COVID-19. Long COVID symptoms adversely affected the day-to-day activities of around 145,000 people (84.3% of those with self-reported long COVID) in Scotland in the four weeks to 5 March 2023 (Figure 1). Of these, around 44,000 (25.6%) reported their ability to undertake their day-to-day activities had been “limited a lot”.

The last release of the ‘Prevalence of ongoing symptoms following coronavirus (COVID-19) infection in the UK’ report (published 30 March 2023) is available on the ONS website.

Figure 1: Long COVID symptoms adversely affected the day-to-day activities of around 145,000 people (101,000 by “a little” and 44,000 by “a lot”).

Number of people living in private households in Scotland with self-reported long COVID, by activity limitation due to long COVID, four-week periods ending 2 May 2021 to 5 March 2023. Data for the four-week period ending 31 July 2022 has been excluded due to data quality issues. Estimates before and after this time period, represented by the dashed line, are not directly comparable due to a change in methodology (see the methodology section).

Office for National Statistics (ONS) Winter COVID-19 Infection Study (WCIS)

The Office for National Statistics (ONS) later published estimates of self-reported long COVID prevalence in Scotland using data from the Winter Coronavirus (COVID-19) Infection Study (WCIS), which ran from November 2023 to March 2024. Participants were asked if they would describe themselves as having long COVID, defined the same as in the CIS.

Data from the WCIS estimate around 168,000 (3.2% people living in private households) people in Scotland were experiencing self-reported long COVID in the four weeks to 7 March 2024. This is similar to the estimated percentage reported at the end of the CIS in March 2023 (3.3%), however the estimates from the CIS and WCIS are not directly comparable due to differences in the survey sample and the type of tests used to detect COVID-19.

Of the 168,000 people experiencing self-reported long COVID in Scotland in the four weeks to 7 March 2024, 136,000 (80.6%) reported their long COVID symptoms adversely affected their ability to undertake their day-to-day activities. Of these, around 46,000 (27.5%) reported their ability to undertake their day-to-day activities had been “limited a lot”.

The full report on ‘Self-reported COVID-19 infections and associated symptoms’ (published 25 April 2024) is available on the ONS website.

Scottish Health Survey (SHeS)

The Scottish Health Survey (SHeS) provides a detailed picture of the health of the Scottish population in private households.

SHeS asked participants questions on long COVID for the first time in 2021. Participants who had had COVID-19 were asked whether they would describe themselves as currently having long COVID: that is, they were still experiencing symptoms more than 4 weeks after they first had COVID-19, which were not explained by something else. SHeS estimated 5% of adults and 1% of children (up to 15 years old) in Scotland were experiencing self-reported long COVID in 2021.

SHeS 2022 amended the 2021 questions so that respondents were not asked explicitly if they would describe themselves as having long COVID. Instead, respondents who had ever had COVID-19, and who had experienced any of a range of symptoms that could not be explained by ‘something else’ for 4 weeks or more, were included in the totals who had long COVID. Additional estimates published at a later date provided a distinction between currently had and ever had long COVID prevalence. SHeS estimated 6% of adults and 4% of children (up to 15 years old) in Scotland currently had long COVID in 2022.

Although these two estimates both measure current prevalence, due to the differences in question wording, the estimates for 2021 and 2022 are not directly comparable. Additionally, estimates from SHeS are not comparable with the existing estimates published by ONS, or the new estimates presented in this report, due to differences in collection mode and differences in overall survey context.

Estimates of long COVID from the 2021 and 2022 SHeS are available on the Scottish Government website.