Incidence rates and symptomatology of community infections with SARS-CoV-2 in children and parents: The CoKids longitudinal household study

  1. MLA de Hoog
  2. JGC Sluiter-Post
  3. I Westerhof
  4. E Fourie
  5. VD Heuvelman
  6. TT Boom
  7. SM Euser
  8. P Badoux
  9. C Reusken
  10. LJ Bont
  11. L Sanders
  12. VWV Jaddoe
  13. BL Herpers
  14. D Eggink
  15. JG Wildenbeest
  16. L Duijts
  17. MA van Houten
  18. PCJL Bruijning-Verhagen

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

AIM

The CoKids study aimed to estimate the community incidence of symptomatic and asymptomatic SARS-CoV-2 in children and parents and to assess the symptomatology of SARS-COV-2 infections relative to SARS-CoV-2 negative respiratory episodes.

METHODS

In this prospective study, households with at least one child <18 years were recruited from three existing Dutch cohorts. Participation included SARS-CoV-2 screening at 4-6 weeks intervals for all household members during 23 weeks of follow-up and active reporting of new onset respiratory symptoms until July 1 st 2021. Follow-up was temporarily intensified following new onset respiratory symptoms in a household member or a SARS-CoV-2 positive screening test and included daily symptom recording, repeated PCR testing (nose-throat, saliva and fecal samples) and SARS-CoV-2 antibody measurement (paired dried blood spots) in all household members. Age-stratified incidence rates for SARS-CoV-2 positive and negative episodes were calculated. Symptomatology and disease burden of respiratory episodes were compared by SARS-CoV-2 status and age.

RESULTS

In total 307 households were enrolled including 1209 subjects. We detected 64 SARS-CoV-2 positive and 118 SARS-CoV-2 negative respiratory outbreaks. The highest incidence rate was found in children <12 years for SARS-CoV-2 negative episodes (0.93/ person-year (PY); 95%CI: 0.88-0.96). The SARS-CoV-2 incidence in this age-group was 0.21/PY for confirmed only, and 0.41/PY if probable cases were included. SARS-CoV-2 incidence did not differ by age group (p>0.27). Nasal congestion/runny nose, with or without cough and fatigue were the three most prevalent symptom clusters for both SARS-CoV-2 positive and negative respiratory episodes. Among children, no differences were observed in the symptomatology and severity of SARS-CoV-2 positive versus negative respiratory episodes, whereas among adults, SARS-CoV-2 positive episodes had a higher number and severity of symptoms and with a longer duration p<0.001).

CONCLUSION

Using active, longitudinal household follow up, we detected a high incidence rate of SARS-CoV-2 infections in children that was similar to adults. The findings suggest that after 20 months of COVID-19 pandemic, up to 2/3 of Dutch children < 12 years have been infected with SARS-CoV-2. Symptomatology and disease severity of SARS-CoV-2 in children is similar to respiratory illness from other causes. In adults, SARS-COV-2 positive episodes are characterized by more and prolonged symptoms, and higher severity. These findings may assist decisions on COVID-19 policies targeting children.

Article activity feed

  1. ScreenIT

    SciScore for 10.1101/2021.12.10.21267600: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: This study was reviewed and ethically approved by the Medical Ethical Committee of the Vrije Universiteit university Medical Centre (VUmc), The Netherlands (reference number A2012.901), the Medical Ethical Committee Utrecht, The Netherlands (reference number 17-069/M) and the Medical Ethical Committee of Erasmus MC, The Netherlands (reference number MEC-2020-0609).
    Consent: Written informed consent was obtained from all participating household members and/or their legal representatives.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    In addition, all household members collected a dried blood spot by self-finger-prick at the start of the outbreak study and ten days after completion of the outbreak period (convalescent sample) to assess the presence of antibodies against SARS-CoV-2.
    SARS-CoV-2
    suggested: None

    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:
    Our study has some limitations that need to be addressed; First, despite the extensive sampling protocol, it is possible that SARS-CoV-2 infections were underdetected to some extent due to missing outbreak samples or asymptomatic infections in-between screenings. Sample completeness was high for the initial outbreak samples, but declined thereafter and convalescent serology was only available for 48.8% and 63.3% of subjects in SARS-CoV-2 positive and negative outbreaks, respectively. We therefore believe that the incidence and attack rates reported in this study should be interpreted as minimum values, rather than averages. Similarly, the true proportion of asymptomatic infections could be somewhat higher than estimated in this study. Second, a large fraction of the observation time fell in the period when the alpha variant of SARS-CoV-2 was dominant in the Netherlands. The period of extended follow-up mostly covered a period with dominance of the Delta variant. Although symptomatology appears not to be different for alpha versus delta, it is possible that household transmission rates were higher during delta dominance, which is only minimally captured in our data (three SARS-CoV-2 outbreaks were studied during extended follow-up). Alternatively, more parents received COVID-19 vaccination during the extended follow-up period and this most likely lowered infection rates among these households. It is unlikely that vaccination had significant impact on the results of the core st...

    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

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2021.12.10.21267600v1 on medRxiv