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Not Reassuring | Zoe App Research into Long Covid in Children

We need to be cautious about the use of language when talking about the health of our children in a pandemic. False narrative may cause a change in behavioural patterns resulting in more unnecessary chronic health.

Throughout the pandemic parents have been subjected to a continual stream of misinformation and mixed messaging. Whilst more adults suffer from Covid harm, it does not make the harm to children disappear. The term ‘fallacy of relative privation’ is a false minimisation of one harm by focusing attention on more severe harm. This process has been used to continuously minimise Covid harm in children and today this theme was intensified by a new study.

The Lancet published,




The study reports that "only 1.8% of children experienced symptoms for at least 56 days" a choice of words that has filled headlines across mainstream media, causing concern and unfathomable heartache among members of the Long Covid Kids Support group.


How many people will have read these articles and change their behaviour because of them?








The majority of Long Covid Kids support group families report experiencing difficulties in accessing support for their children, some of whom have children who have been ill for up to 18 months. Such distorted media representation will not improve their situation.


The 15 promised paediatric Long Covid hubs do not treat or cure Long Covid. In fact, our members have struggled to access them, not least because many are not yet operational.


Stop, breathe and think through these headlines.


In reality the figure quoted in the Zoe App research equates to approximately two in every 100 confirmed child cases that could suffer from Long Covid. That isn't rare. Or infrequent. Further, the 4.4% figure quoted suggests that around one child in every class could suffer from Long Covid.


Do these figures sound reassuring?




1% is common for an illness. Covid is significantly more common than many other illnesses.  Symptom presentation is significant.



Over the last month, COVID-19 has been ripping through schools and the wider community. Children’s Covid cases and Covid only hospital admissions have far exceeded the peak of the second wave, rising faster than ever before and the study in question predates the current more transmissible Delta variant.


According to the UK governments own data 953,000 children are known to have been infected with COVID-19 so far. Even allowing for the flawed study figures, imagine a policy allowing infection in children knowing more than 4 in 100 may suffer long lasting adverse reactions.




Elaine Maxwell NIHR Scientific Advisor for the National Institute for Health Research (NIHR) said;


"The Zoe App is a self selected group and has consistently reported lower rates of Long Covid in adults than other studies. As they note, in March 21 they reported adult prevalence of Long Covid as 2.3% at 12 weeks, compared to the ONS April 21 report of 13.7% at 12 weeks and the REACT2 (June 21) finding of more than a third of adults still reporting symptoms at 12 weeks. The ONS study compared nearly 21,000 people with confirmed Covid19 with a non Covid control group and found a significant difference, suggesting it was not simply pandemic related health anxiety.
Three recent very large US insurance claims studies recently put the figure for adults with Long Covid between 14-20% of those infected with Covid19 as having post acute sequelae of Covid19 for 12 weeks or more – including those who were initially asymptomatic.
Insurance claims rely on a medical practitioner’s medical diagnosis rather than self reporting of symptoms. The FAIRHEALTH report includes claims for Long Covid in children in some detail, noting presentations are different in children
The Zoe APP is a significant outlier of prevalence estimates in adults and it is therefore probably not a surprise that their estimate in children is also low. They report 4.4% of children who tested positive experienced symptoms lasting for 4 weeks or more (about a third of the 13.3% they previously reported for adults at 4 weeks). This ratio is similar to the ONS April21 findings that children and young people report Long Covid at about half the rate that adults do.
We don't understand the natural history of Long Covid in adults let alone in children. ONS publish new data on Thursday 5th August but in July they estimated 26,000 children had been ill for 12 weeks and 9,000 for over 12 months and this has increased month on month since March."
Updated at time of publishing - New ONS data 34,000 under 16s report Long Covid




Long Covid Kids are concerned that there are some considerable limitations with this latest research. 


This current study requires a positive test for Covid-19 but access to testing was still challenging for children in January 2021.


  • The study states that children with a one-week gap in symptoms were excluded. This undermines the fundamental basics that we know for certain - Long Covid has relapsing and remitting symptoms.


  • The study measures the number of symptoms as a proxy for severity rather than the degree of disability.


  • It is proxy-reported, non-randomised data from symptomatic children. It does not include control data for asymptomatic children or children without Covid.


  • The data for the research is collated from mobile app recording therefore does not fully represent the children and young person population.


  • Selection bias is therefore a big issue. Which parent downloads the app and which parent continues to log symptoms.


  • Parents using the app are likely to be an under-representation of vulnerable and disadvantaged children.


  • The authors are relying on parents busy looking after sick children to self-report a plethora of symptoms themselves, with no benefit to them or to their poorly child for protracted periods of time. It has been reported on social media that “frustration” and “boredom” have resulted in lack of continued engagement with the app.


  • Sadly, the authors made the same errors when reporting Long Covid prevalence in adults almost a year ago. Study design could have been improved for the benefit of this research. Why didn’t the authors improve their study design or at least outline the limitations more clearly?


  • The authors record a median illness duration of 6 or 7 days and only 77 were sick for more than 28 days


  • The study excludes the onset of symptoms after 5 weeks, which shows a lack of understanding of the nature of Long Covid.


  • This study stopped reviewing children at 56 days of symptoms. Yet anecdotal evidence from lived experience reports a period of 'wellness' between COVID-19 infection, before developing Long Covid symptoms after 5 weeks. 


  • This is a parental report. We need to be sure about children's experience. When LCK produced parental-reported data it was criticised by a member of the ZOE app.


  • 161 families who had been logging stopped before 28 days. The authors have interpreted this as recovery. Given that they only had 77 with illnesses longer than 28 days, if that assumption is incorrect, it could make quite a big difference to the findings.



On the surface of it, this study seems to be reassuring, suggesting a very low prevalence of Long Covid in children. However, under closer scrutiny, this is a very flawed study that offers false reassurance to parents which may result in an increase in infections and ultimately an increase in long term harm to children. Indeed, this research could be viewed as dangerous due to the limitations of the study and the extent of its reach in the media.


To report on Long Covid in children you need to understand Long Covid in children. Long Covid Kids are working with a number of excellent researchers who understand the importance of collaboration with lived experience and demonstrate a genuine curiosity.



As people with the lived experience, representing a community of families with Long Covid, we have the following questions:

Were these children given a follow-up for up to at least six months to see if their recovery continued?


Were parents and children with lived experience consulted in the design of the study?




High numbers of children are contracting Covid. Even if the figure from this flawed study of 1% were true, that would still be a lot of children.


Since Autumn 2020 Long Covid Kids have been calling for a clear child-focused COVID-19 public awareness campaign. To date, this has not materialised. 

Lack of awareness continues to frustrate the recording of the true data and until we have a clinical definition for Long Covid in children, we must consider the way Long Covid has been measured in every published study. 

The CDC has displayed a comprehensive list of symptoms since earlier this year but this information continues to be missing from the NHS and Government website. 



Lack of information has resulted in a lack of testing and recording in the UK.

How many children in the general population will not have had a PCR test due to lack of symptom awareness or due to asymptomatic presentation and will therefore not have been recorded either by the government or Covid ZOE?

Anecdotally from our support group we see children whose health has been significantly impacted by chronic and disabling symptoms for up to 18 months. It is encouraging that a small number of families have started to report some improvements.

However we are not yet seeing posts from families who can confirm their child has returned to their pre-Covid health.

This study, at best, is a piece in the puzzle, but it is definitely not the complete picture. 


LongCovidKids.org is a patient-led advocacy and support organisation led by Sammie Mcfarland for families of children with Long Covid. Our story started with a short film on long-lasting symptoms of Covid in children.


We are supporting research with The Long Covid Kids Study with PeopleWith.


Each Sunday we send out a newsletter providing a weekly round up of statistics, latest reports in the media, current research, as well as LCK news. Read previous issues and SIGN UP





If your child experiences any symptoms that indicates they are unwell, it COULD be COVID-19, and you should get them a test to help identify if it is a current Covid infection. Please see our Frequently Asked Questions page for more information.

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