Assessment of SARS-CoV-2 infection by Reverse transcription-PCR and serology in the Paris area: a cross-sectional study

  1. Robert Cohen
  2. Camille Jung
  3. Naim Ouldali
  4. Aurelie Sellam
  5. Christophe Batard
  6. Fabienne Cahn-Sellem
  7. Annie Elbez
  8. Alain Wollner
  9. Olivier Romain
  10. François Corrard
  11. Said Aberrane
  12. Nathalie Soismier
  13. Rita Creidy
  14. Mounira Smati-Lafarge
  15. Odile Launay
  16. Stéphane Béchet
  17. Emmanuelle Varon
  18. Corinne Levy

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Abstract

Several studies indicated that children seem to be less frequently infected with SARS-CoV-2 and are potentially less contagious than adults. To examine the spread of SARS-CoV-2, we combined both Reverse transcription-PCR testing and serology in children in the most affected region in France, Paris, during the COVID-19 epidemic.

Methods

From 14 April 2020 to 12 May 2020, we conducted a cross-sectional, prospective, multicentre study. Healthy controls and pauci-symptomatic children from birth to age 15 years were enrolled by 27 ambulatory paediatricians. A nasopharyngeal swab was taken for detection of SARS-CoV-2 by Reverse transcription-PCR and a microsample of blood for micromethod serology.

Results

Among the 605 children, 322 (53.2%) were asymptomatic and 283 (46.8%) were symptomatic. Reverse transcription-PCR and serology results were positive for 11 (1.8%) and 65 (10.7%) children, respectively, with no significant difference between asymptomatic and pauci-symptomatic children. Only three children were Reverse transcription-PCR-positive without any antibody response detected. The frequency of Reverse transcription-PCR SARS-CoV-2 positivity was significantly higher for children with positive than negative serology results (12.3% vs 0.6%, p<0.001). Contact with a person with confirmed COVID-19 increased the odds of Reverse transcription-PCR positivity (OR 7.8, 95% CI 1.5 to 40.7) and serology positivity (OR 15.1, 95% CI 6.6 to 34.6).

Conclusion

In an area heavily affected by COVID-19, after the peak of the first epidemic wave and during the lockdown, the rate of children with Reverse transcription-PCR SARS-CoV-2 positivity was very low (1.8%), but that of serology positivity was higher (10.7%). Most children with positive Reverse transcription-PCR results also had positive serology results.

Trial registration number

NCT04318431 .

Article activity feed

  1. Version published to 10.1136/bmjpo-2020-000887
  2. Version published to 10.1101/2020.06.12.20129221v2 on medRxiv
  3. ScreenIT

    SciScore for 10.1101/2020.06.12.20129221: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: After informing the parents of the participating children and obtaining their signed consent, an electronic case report form (eCRF) was completed by the pediatrician to collect socio-demographic data, history, contact with a person with confirmed COVID-19 by RT-PCR SARS-CoV-2, clinical symptoms and signs, and additional positive biological tests.
    IRB: All tests were 2-sided and were considered significant at p<0.05. Ethics: The study protocol was approved by an ethics committee (CPP IDF IX no. 08-022).
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Serological assays: Pediatricians collected fingerstick whole-blood specimens and used the Biosynex COVID-19 BSS test, a rapid chromatographic immunoassay, for qualitive detection of IgG and IgM antibodies to SARS-CoV-2 in blood.
    IgM
    suggested: None
    Software and Algorithms
    SentencesResources
    The RT-PCR for SARS-CoV-2 was performed on the automated Seegene STARlet system®, according to the manufacturer’s instructions using the CE marked AllplexTM 2019-nCoV RT-PCR assay (Seegene, South Korea®) which targets N- (viral nucleocapsid protein) and RdRP-gene (RNA-dependent RNApolymerase), both SARS-CoV-2 specific genes, and the sarbecovirus specific E-gene.
    SARS-CoV-2
    suggested: (Active Motif Cat# 91351, RRID:AB_2847848)
    Statistical analysis: Data were entered by using the eCRF (PHP/MySQL) and analyzed by using Stata/SE v15 (StataCorp, College Station, TX, USA).
    StataCorp
    suggested: (Stata, RRID:SCR_012763)

    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 several limitations. First, the role of assumed household transmission probably has been over-estimated because of the well-followed lockdown in France.35 Indeed, more than 86.5% of children with positive SARS-CoV-2 by RT-PCR or serology have had a confirmed or suspected COVID-19 household contact. However, our rate of positive serology for children in the Paris area was similar to the rate observed for hospitalized patients (11.7%) and at school children (8.8%).22, 36 Second, the ability to successfully collect nasopharyngeal swabs properly could be more difficult in young children and significantly affect the results and be a factor contributing to the low RT-PCR positivity prevalence observed in our population. However, the pediatricians who performed the study were all involved for many years in a pneumococcal nasopharyngeal carriage study (started in 2001 and currently ongoing) and were particularly well trained to collect appropriately nasopharyngeal samples.37 School closure or limitation (reduced number of students or days of attendance) has a major impact on children’s development and access to learning.38 Therefore, the usefulness of school closure or limitation needs evaluation in controlling the COVID-19 epidemic. 39 We plan to renew this study after the full re-opening of schools and day care centre in the Paris area to better assess the transmission of SARS-Cov-2 in children.

    Results from TrialIdentifier: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    NCT04318431CompletedPrevalence of SARS -Cov2 Carriage in Asymptomatic and Mildly…

    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.

    About SciScore

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  4. Version published to 10.1101/2020.06.12.20129221v1 on medRxiv