UPDATE: COVID19 Questionnaire, PEME/PESE, the Office For National Statistics, and the University of Oxford

This post is an update to our blog post – ‘COVID19 Questionnaire, PEM/PESE, and the Office For National Statistics

This is an ongoing issue that we have been working on for a while. Please read the blog mentioned above to see information on our work so far.

As we wrote at the bottom of the aforementioned blog-

Questions must surely be asked as to why a question about one of the ‘common’ symptoms of Long Covid is not included on this important questionnaire. PEM/PESE is a symptom of Long Covid because half of Long Covid cases meet the diagnostic criteria for M.E/C.F.S. We believe that a deliberate decision must have been made to exclude this symptom/characteristic from the data collection.

This data would be supplementary to research estimates and would reinforce the anecdotal knowledgebase.

The M.E/C.F.S community need every bit of data available, that includes data on PEM/PESE amongst the Long Covid patient community.

This is a work in progress.

After posting this blog, we wrote to the Office of National Statistics again, see an extract of our correspondence below-

15th August 2022 email (extract) to ONS

A FOI request has advised that ‘We have spoken with the relevant team and we can confirm that no decision has been made NOT to include PEM in our questionnaire’.

I’m assuming you are the ‘team’ that they spoke to.

I have looked at the questionnaires that participants fill in and ‘weakness/fatigue’ would be the best fit. But, PEM is not ‘weakness/fatigue’. Back when the questionnaire was first created by Oxford, were patients giving freeform answers? With half of Long Covid patients experiencing PEM (they must do as half meet M.E criteria), it is hard to understand why they wouldn’t mention ‘crashing’ after exertion even if they did not know the official name for it. It is the defining characteristic of our illness and it is an exacerbation of many symptoms – inc pain, headaches, nausea, visual disturbances, slurred speech etc.

15th August 2022 FOI request submitted to Nuffield Department of Medicine (University of Oxford)

Please provide all information you hold on why Post-Exertional Malaise is NOT included on
the ‘self-reported’ symptoms list on the COVID19/Long Covid questionnaire supplied to the
Office of National Statistics.
Was Post-Exertional Malaise (possibly self-reported as ‘crashing’ or ‘a flare’) self-reported
when the symptoms list was first researched in 2020/21?

This week, we received a reply from the Office for National Statistics and a response to our Freedom of Information request from the University of Oxford.

12th September 2022 email (extract) received from ONS

Hi Sally

First, to address your specific questions/comments. We didn’t intend for ‘weakness/fatigue’ to cover PEM, and we have never included free-form text boxes for symptoms not listed on the questionnaire. As we were preparing the wording of the new Long Covid question for the Coronavirus Infection Survey (CIS), we conducted a rapid and pragmatic review of the available literature to determine the initial symptom list. This was back in the autumn of 2020, so the evidence base was much more limited than it is now, and PEM didn’t come through as one of the “top symptoms” of Long Covid at the time. As you say, we now know from multiple studies that PEM is a defining characteristic of Long Covid.

We are open to changing and improving the questionnaire, and you might have noticed that we’ve expanded the symptom list on the CIS over time, from an initial 12 up to 23 today. We didn’t include PEM as one of these additional symptoms because it is reflects an overall worsening of one or more symptoms, rather than being an individual symptom per se, and would therefore require a separate question of its own (e.g. “Do any of the above symptoms get worse after a period of physical or mental exertion?”).

With this in mind, I thought it would be helpful to provide a bit of detail around the process and challenges of adding new questions to the survey. Firstly, the CIS is governed by a pre-registered study protocol, and has been approved by a medical ethics committee on the basis of this protocol. Any significant deviation from the study objectives as laid out in the protocol may necessitate re-applying for ethical approval. Given that the primary objective of the study is to measure the prevalence of SARS-CoV-2 infection, we are limited with what we can add on other subjects (moreover, Long Covid is listed as an exploratory objective, behind the primary objective, five secondary objectives, and three other exploratory objectives). Secondly, adding new questions incurs a financial cost (e.g. to pay for changes to data collection software, changes to processing systems, testing and quality assurance, etc), and so funding would need to be found. Thirdly, we need to consider the burden being placed on respondents, as each new question means having to spend more time completing the questionnaire (particularly as participants are followed-up on a monthly basis), and therefore potentially reduced data quality and/or response rates. The benefit of any new questions (which are sometimes competing for space on the questionnaire) therefore needs to be weighted against the impact on respondent burden. As you can imagine, all of these considerations mean that getting even a single new question added to the survey is not quick or easy, and there’s a considerable amount of governance and process involved.

In summary, while we completely agree that having a question on PEM would be beneficial and insightful [ ] adding such a question would involve a fair amount of work and therefore needs to be weighted up against other analytical priorities within the team at any given time.  As I think was said in the FOI response, it’s not that we’ve ruled out adding a question on PEM to the survey (quite the opposite), it’s simply that we haven’t been able to dedicate resource to initiate the process of adding it. This remains on our priority list for the rest of the year, and we hope to be able to get to it soon, now that the transition to remote data collection is largely complete.

I hope this explanation is helpful and provides some reassurance.

Kind regards,


XXXXXX | Principal Statistician

Office for National Statistics | Swyddfa Ystadegau Gwladol


13th September 2022 FOI response from the University of Oxford

Dear Ms Callow

I write in reply to your email requesting the above information.

The University does not hold any information concerning a specific decision not to include Post-Exertional Malaise
in the symptoms list for the Covid-19 questionnaire supplied to the Office for National Statistics.

For context, long Covid was not part of the original objectives for this study, but was added as an exploratory
objective in version 12.0 of the survey. The original symptom list was supplemented with the most common long COVID symptoms based on a rapid pragmatic
literature review and discussion with patients in late 2020 (led by the Office for National Statistics), however no
records of the discussion of which symptoms should be included have been retained by the University of Oxford,
since this work was led by the Office for National Statistics. Please note that “weakness/tiredness” has been
included as a symptom since the start of the survey.

Yours sincerely

Information Compliance Team

Where do we go from here?

We are grateful for the comprehensive response from the ONS and for pieces of the puzzle being provided by the University of Oxford. However, none of this information gets us any closer to having PEM/PESE included in the UK COVID19 questionnaire. Perhaps if M.E/C.F.S had been much better understood prior to the pandemic, the initial COVID19 survey would have pre-empted that chronic illness, specifically M.E/C.F.S, would have been an important part of the survey AS A PRIMARY OBJECTIVE and PEM/PESE would have been included from the outset.

But, we are where we are, and M.E/C.F.S is not included within this ONS data due to the absence of PEM/PESE.

This is an issue that Stripy Lightbulb CIC will be monitoring for future developments.



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