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Consent for covid-19 vaccination in children

BMJ 2021; 374 doi: (Published 28 September 2021) Cite this as: BMJ 2021;374:n2356

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Long Covid in Children: ONS Prevalence estimates have been radically revised downwards

Dear Editor,

We read with interest Majeed and colleagues’ examination of specific consent-issues regarding Covid-19 vaccines in children given what they describe as a “finely balanced risk-benefit profile” for vaccination [1]. In our previous letter (“Vaccinating children to prevent long covid? More caution is needed in interpreting current epidemiological data”), published in February 2021[2] we warned that Office for National Statistics (ONS) data on post Covid-19 symptoms were not at that time fit for the purpose of informing medical- and public-health decisions in children because symptoms often ascribed to this condition are very common and non-specific, and because of a lack of a comparator group of non-infected children for proper comparison of prevalence estimates. The figures quoted at that time (12.9% or primary-school aged, and 15% of secondary-school aged children displaying one of twelve symptoms at five-weeks post-infection) were being frequently discussed including in the mainstream media[3]. The fact-checking website FullFact ran a piece encouraging more thoughtful discussion in March 2021[4]. Nonetheless, we continued to observe these data being used uncritically and think it is possible that these ideas remain in the mind of the public, although we see that official consent-materials for children state “For most children and young people COVID-19 is usually a milder illness that rarely leads to complications. For a very few the symptoms may last for longer than the usual 2 to 3 weeks.”[5].

We therefore were pleased to note further ONS data-releases on the subject. In April 2021, similar estimates were revised downwards considerably to 7.4% (primary-school aged) and 8.2% (secondary school aged children)[6]. In September 2021 these were further revised downwards to 3.3% (95%CI 2.5-4.5) in primary-school aged children and 4.6% (95%CI 3.5-6.0) in those of secondary-school age for children at 4-8 weeks post-infection. Crucially, in these latest figures a matched-control group of children had similar prevalence of ‘long covid’ despite being likely to have never had Covid-19 disease (3.6% [95%CI 2.7-4.8] and 2.9% [95%CI 2.1-4.0] for primary- and secondary-school aged children respectively) [7] . Reduced prevalence estimates and similarity with controls are also seen in equivalent figures for those with continuous symptoms, and for those with who self-reported positively in response to the question “Would you describe yourself as having ‘long COVID’, that is, you are still experiencing symptoms more than 4 weeks after you first had COVID-19, that are not explained by something else?”.

It is clear to us that early concerns over high prevalence of post-covid syndromes were exaggerated. This may have been due to outcome-misclassification bias in the ONS data (see Figure 3 [7]), issues with long-term follow up for symptoms beyond 12-weeks post-infection, lack of a test-negative comparator-group in early ONS data releases and in other studies, and lack of a child-specific definition for post-covid syndrome given that we know ‘children are not small adults’ (this is under development [8]). Whatever the reasons, in our view, public discussions on ‘Long Covid’ and children have not always helped children, their parents and caregivers. We continue to encourage both a more cautious approach in applying adult-focussed epidemiological methods to children, and support for all children who need it throughout and beyond the remaining pandemic period.

1 Majeed A, Hodes S, Marks S. Consent for covid-19 vaccination in children. BMJ 2021;374:n2356. doi:10.1136/bmj.n2356
2 Bhopal SS, Absoud M. Vaccinating children to prevent long covid? More caution is needed in interpreting current epidemiological data. BMJ 2021;372:n520. doi:10.1136/bmj.n520
3 Updated estimates of the prevalence of long COVID symptoms - Office for National Statistics. (accessed 3 Feb 2021).
4 Extrapolating figures around long Covid in kids is not the way to go. Full Fact. (accessed 25 Mar 2021).
5 COVID-19 vaccination: a guide for eligible children and young people aged 12 to 17. GOV.UK. (accessed 4 Oct 2021).
6 Prevalence of ongoing symptoms following coronavirus (COVID-19) infection in the UK - Office for National Statistics. (accessed 4 Oct 2021).
7 Office for National Statistics. Technical article: Updated estimates of the prevalence of post-acute symptoms among people with coronavirus (COVID-19) in the UK: 26 April 2020 to 1 August 2021.
8 Public Health England & UCL. Children and young people with Long Covid (CLoCK).

Competing interests: No competing interests

04 October 2021
Sunil S Bhopal
Academic Clinical Lecturer in Population Health Paediatrics
Michael Absoud, consultant & senior clinical lecturer in paediatric neurodisability, Evelina London Children' Hospital, UK & Department of Women and Children's Health, King's College London, UK
Newcastle University Population Health Sciences Institute
Newcastle upon Tyne