Illness Characteristics of COVID-19 in Children Infected with the SARS-CoV-2 Delta Variant

  1. Erika Molteni
  2. Carole H. Sudre
  3. Liane Dos Santos Canas
  4. Sunil S. Bhopal
  5. Robert C. Hughes
  6. Liyuan Chen
  7. Jie Deng
  8. Benjamin Murray
  9. Eric Kerfoot
  10. Michela Antonelli
  11. Mark Graham
  12. Kerstin Kläser
  13. Anna May
  14. Christina Hu
  15. Joan Capdevila Pujol
  16. Jonathan Wolf
  17. Alexander Hammers
  18. Timothy D. Spector
  19. Sebastien Ourselin
  20. Marc Modat
  21. Claire J. Steves
  22. Michael Absoud
  23. Emma L. Duncan

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Abstract

Background: The Delta (B.1.617.2) SARS-CoV-2 variant was the predominant UK circulating strain between May and November 2021. We investigated whether COVID-19 from Delta infection differed from infection with previous variants in children. Methods: Through the prospective COVID Symptom Study, 109,626 UK school-aged children were proxy-reported between 28 December 2020 and 8 July 2021. We selected all symptomatic children who tested positive for SARS-CoV-2 and were proxy-reported at least weekly, within two timeframes: 28 December 2020 to 6 May 2021 (Alpha (B.1.1.7), the main UK circulating variant) and 26 May to 8 July 2021 (Delta, the main UK circulating variant), with all children unvaccinated (as per national policy at the time). We assessed illness profiles (symptom prevalence, duration, and burden), hospital presentation, and presence of long (≥28 day) illness, and calculated odds ratios for symptoms presenting within the first 28 days of illness. Results: 694 (276 younger (5–11 years), 418 older (12–17 years)) symptomatic children tested positive for SARS-CoV-2 with Alpha infection and 706 (227 younger and 479 older) children with Delta infection. Median illness duration was short with either variant (overall cohort: 5 days (IQR 2–9.75) with Alpha, 5 days (IQR 2–9) with Delta). The seven most prevalent symptoms were common to both variants. Symptom burden over the first 28 days was slightly greater with Delta compared with Alpha infection (in younger children, 3 (IQR 2–5) symptoms with Alpha, 4 (IQR 2–7) with Delta; in older children, 5 (IQR 3–8) symptoms with Alpha, 6 (IQR 3–9) with Delta infection ). The odds of presenting several symptoms were higher with Delta than Alpha infection, including headache and fever. Few children presented to hospital, and long illness duration was uncommon, with either variant. Conclusions: COVID-19 in UK school-aged children due to SARS-CoV-2 Delta strain B.1.617.2 resembles illness due to the Alpha variant B.1.1.7., with short duration and similar symptom burden.

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  1. Version published to 10.3390/children9050652
  2. ScreenIT

    SciScore for 10.1101/2021.10.06.21264467: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsIRB: Ethics approval for this study was granted by the KCL Ethics Committee (LRS-19/20-18210).
    Consent: Upon registration through the app, all participants provided consent for their data to be used for COVID-19 research.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    16 All analyses were performed in Python version 3.7.
    Python
    suggested: (IPython, RRID:SCR_001658)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    We recognise other weaknesses of our study. Our study only assesses illness profile in symptomatic children. We are not able to comment on relative transmissibility or on prevalence of asymptomatic infection with Alpha vs. Delta variants. We only present data for symptoms assessed by direct questioning through the app across both timeframes (Supplementary Table 1). Any novel symptoms unique to Delta variant would not be captured by our study. Our current study does not present illness profiles in children with illness for more than 28 days, to avoid bias introduced by our census timing, although we do report the numbers of children with long illness duration which were low with either variant. Our previous study showed that prolonged illness duration in children with COVID-19 is uncommon13 consistent with the most recent (September 16, 2021) publication of the UK ONS Coronavirus Infection Survey: 3.3% (95%CI 2.5-4.5) of children aged 2-11 years testing positive for SARS-CoV-2 had one of 12 symptoms 29-56 days following infection, compared to 3.6% (95%CI 2.7-4.8) in a matched negative control group (noting that this latter study may be more representative of children in the general population than our own,23 and includes children with asymptomatic infection) (https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/articles/technicalarticleupdatedestimatesoftheprevalenceofpostacutesymptomsamongpeoplewithcoronaviruscovid19intheuk/26april2020...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  3. Version published to 10.1101/2021.10.06.21264467v1 on medRxiv