Advertisement

Very low rates of severe COVID-19 in children hospitalised with confirmed SARS-CoV-2 infection in London, England”

  • Borbàla Zsigmond
    Correspondence
    Corresponding author: St. George's Hospital, Department of Paediatric Infectious Diseases, Blackshaw Road, London SW17 0QT, United Kingdom.
    Affiliations
    Department of Paediatric Infectious Diseases, St. George's Hospital, Blackshaw Road, London SW17 0QT, UK

    Immunisation Division, UK Health Security Agency, 61 Colindale Avenue, London, UK
    Search for articles by this author
  • Aodhán Seán Breathnach
    Affiliations
    Department of Infection, St George's University Hospitals NHS Foundation Trust, London, UK

    Immunisation Division, UK Health Security Agency, 61 Colindale Avenue, London, UK
    Search for articles by this author
  • Anna Mensah
    Affiliations
    Institute of Infection and Immunity, St George's University of London, UK

    Immunisation Division, UK Health Security Agency, 61 Colindale Avenue, London, UK
    Search for articles by this author
  • Shamez N Ladhani
    Affiliations
    Department of Paediatric Infectious Diseases, St. George's Hospital, Blackshaw Road, London SW17 0QT, UK

    Department of Infection, St George's University Hospitals NHS Foundation Trust, London, UK

    Institute of Infection and Immunity, St George's University of London, UK

    Immunisation Division, UK Health Security Agency, 61 Colindale Avenue, London, UK
    Search for articles by this author
Published:April 10, 2022DOI:https://doi.org/10.1016/j.jinf.2022.04.020

      Graphical abstract

      We read with interest the publication by Chappell et al. reporting a very low risk of severe COVID in immunosuppressed children in England.
      • Chappell H.
      • Patel R.
      • Driessens C.
      • et al.
      Immunocompromised children and young people are at no increased risk of severe COVID-19.
      Compared to adults, children and young people (CYP) are more likely to remain asymptomatic or develop mild symptoms when exposed to SARS-CoV-2, and less likely to develop severe disease, be hospitalised, or die of COVID-19.
      • Castagnoli R.
      • Votto M.
      • Licari A.
      • et al.
      Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children and adolescents: a systematic review.
      In adults, hospitalisation and case fatality rates due to COVID-19 are regularly used to measure disease severity with new variants and following vaccination.
      • Andrews N.
      • Tessier E.
      • Stowe J.
      • et al.
      Duration of protection against mild and severe disease by Covid-19 vaccines.
      The disconnect between infection and severe disease after successful COVID-19 immunisation programmes, for example, has been a primary driver for many countries to remove mitigations even with the emergence of more transmissible variants.
      In CYP, COVID-19 fatalities are rare and the use of COVID-19 hospitalisations as a proxy for disease severity,
      • Gurdasani D.
      • Bhatt S.
      • Costello A.
      • et al.
      Vaccinating adolescents against SARS-CoV-2 in England: a risk-benefit analysis.
      is questionable because of the high rates of incidental (asymptomatic or mild) infections identified during routine SARS-CoV-2 screening of all CYP presenting to hospital. Two years into the pandemic, there are still limited data on the risk of hospitalisation for severe COVID-19 in CYP. We, therefore, undertook a retrospective case-note review of CYP admitted to a large paediatric hospital in London with PCR-confirmed SARS-CoV-2 infection over 14-month period covering the alpha, delta and omicron variant waves (Fig. 1a and b).
      Fig. 1a
      Fig. 1aChildren and young people aged 0–18 years who were admitted to St. George's Hospital, London, with PCR-confirmed SARS-CoV-2 infection and total case numbers for the same age-group in London by month of year during December 2020 to January 2022. The blue bars denote children hospitalised for acute COVID-19, the orange bars denote hospitalisations where SARS-CoV-2 likely contributed to the hospitalisation and the grey bars denote incidental infections in children and young people hospitalised with other medical conditions.
      Fig. 1b
      Fig. 1bChildren and young people aged 0–18 years who were admitted to St. George's Hospital, London, with PCR-confirmed SARS-CoV-2 infection by age-group during December 2020 to January 2022. The blue bars denote children hospitalised for acute COVID-19, the orange bars denote hospitalisations where SARS-CoV-2 likely contributed to the hospitalisation and the grey bars denote incidental infections in children and young people hospitalised with other medical conditions.
      St. George's Hospital is a large teaching hospital providing acute paediatric A&E, general and specialist paediatric, oncological, surgical and neurosurgical, orthopaedic and trauma, NICU and PICU care for children in South London. CYP aged 0–18 years with a SARS-CoV-2 PCR-positive result between 01 December 2020 and 31 January 2022 were identified through the hospital microbiology laboratory database and their electronic medical records reviewed by two independent paediatricians. Case rates for 0–18-year-olds in London were obtained from national community testing data.

      UK Health Security Agency. Official Statistics: National flu and COVID-19 surveillance reports: 2021 to 2022 season. Available at: https://www.gov.uk/government/statistics/national-flu-and-covid-19-surveillance-reports-2021-to-2022-season (accessed 05 February 2022.

      We excluded children with PIMS-TS, which typically occurs 2–6 weeks after SARS-CoV-2 infection by which time SARS-CoV-2 PCR-tests are usually negative. Confirmed cases were categorised into:
      • (i)
        Incidental: admitted for an unrelated illness, but SARS-CoV-2 PCR-positive on routine screening
      • (ii)
        Contributory: SARS-CoV-2 potentially contributed to hospitalisation
      • (iii)
        Severe COVID-19: SARS-CoV-2 was the primary reason for hospitalisation
      During the 14-month period, there were 33,775 CYP A&E attendances and 3593 hospitalisations at St. George's Hospital. Of these, 147 were hospitalised with a positive SARS-CoV-2 PCR-test. The distribution of incidental and contributory cases closely followed community infection rates in London, but hospitalisations for severe COVID-19 occurred mainly during the alpha wave, with very few cases during the delta or omicron waves despite large numbers of community infections in the same age-group.
      Incidental infections accounted for 83 (57%) cases and included CYP admitted for surgical (24/83, 29%), neurological (12/83, 14%), trauma (10/83, 12%) and other illnesses (e.g. eating disorders, neonatal jaundice; 37/83,45%). Cases where SARS-CoV-2 likely contributed to hospitalisation (49/147, 33%) had clinical presentations that were typical of other childhood viral illnesses. Most CYP (32/49, 65%) presented with fever and respiratory symptoms, or fever with inadequate oral intake, which warranted admission for observation and/or sepsis screen with antibiotic cover until bacterial cultures returned negative after 48 h; 26% (13/49) in this category were aged <3 months. Other presentations included acute exacerbation of asthma (7/49, 14%), febrile convulsions (4/49, 8%) and other presentations (e.g. diarrhoea and vomiting, feeding difficulties, lethargy; 6/49, 12%). Symptoms were generally mild and only five required supplemental oxygen during their short hospital stay.
      Thus, only 15 children (10%) were hospitalised with severe COVID-19 presenting as pneumonitis, mainly during the alpha variant wave (10/15, 67%), and in older CYP (9/15 [60%] were aged 12–18 years) with comorbidities (11/15, including 8 with immunosuppression) (Table 1). Thirteen CYP required supplemental oxygen, seven required intensive care and all recovered.
      Table 1Supplement Table. Characteristics, clinical presentation, management and outcomes of children and young people aged 0–18 years with PCR-confirmed SARS-CoV-2 infection who were hospitalised with acute COVID-19 during December 2020 to January 2022.
      AgeUnderlying conditionClinical PresentationHospital daysICU daysOxygenTreatment
      1.‹1 yearPrematurityRespiratory distress, pneumonia33YNone
      2.‹1 yearPrematurity, chronic lung diseaseApnoea, pneumonia86YNone
      3.‹1 yearPrimary immunodeficiencyChronic diarrhoea, failure to thrive, then pneumonia8-NNone
      4.‹1 yearNonePneumonia2-NNone
      5.5–11 yearsMalignancyFebrile neutropaenia29-YSteroids and antivirals
      6.5–11 yearsMalignancyGram-negative bacterial sepsis, then pneumonia132YNone
      7.12–18 yearsMalignancyGram-negative bacterial sepsis, then pneumonia10-YSteroids and antivirals
      8.12–18 yearsMalignancyFebrile neutropenia and pneumonia102Y2 admissions: Steroids and antivirals (1st admission), antivirals (2nd admission)
      9.12–18 yearsChronic heart diseasePneumonia177YSteroids and antivirals
      10.12–18 yearsMalignancyPneumonia101YSteroids and intravenous immunoglobulin
      11.12–18 yearsNonePneumonia6-YSteroids and antivirals
      12.12–18 yearsMalignancyFebrile neutropenia, pneumonia51YSteroids
      13.12–18 yearsPrimary immunodeficiencyProlonged fever10-NAntivirals
      14.12–18 yearsNoneFever and dehydration1-NNone
      15.12–18 yearsChronic liver diseasePneumonia4-YSteroids
      ICU, intensive care unit.
      In our hospital, more than half the CYP hospitalised with a positive SARS-CoV-2 PCR-test had incidental infection. In a further third, SARS-CoV-2 likely contributed to hospitalisation with clinical presentations that were typical of other respiratory viruses that are currently not circulating in England because of the physical distancing measures imposed during various lockdowns.
      • Taylor A.
      • Whittaker E.
      The changing epidemiology of respiratory viruses in children during the COVID-19 pandemic: a Canary in a COVID Time.
      This group included mainly high-risk CYP (young infants, immunocompromised) who typically presented with fever and mild respiratory symptoms but were hospitalised to rule serious underlying infection. Of the few CYP hospitalised with COVID-19 pneumonitis, most were adolescents and nearly all had underlying conditions, especially immunosuppression. They all recovered, consistent with current literature reporting favourable outcomes, including for CYP with comorbidities and immunosuppression.
      • Chappell H.
      • Patel R.
      • Driessens C.
      • et al.
      Immunocompromised children and young people are at no increased risk of severe COVID-19.
      ,
      • Ward J.L.
      • Harwood R.
      • Smith C.
      • et al.
      Risk factors for PICU admission and death among children and young people hospitalized with COVID-19 and PIMS-TS in England during the first pandemic year.
      Vaccinating children against COVID-19 will further reduce the small risk of severe disease,
      • Powell A.A.
      • et al.
      Adolescent vaccination with BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine and effectiveness of the first dose against COVID-19: national test-negative case-control study, England.
      • Prunas O.
      • Weinberger D.M.
      • Pitzer V.E.
      • et al.
      Waning effectiveness of the BNT162b2 vaccine against infection in adolescents.
      • Olson S.M.
      • Newhams M.M.
      • Halasa N.B.
      • et al.
      Effectiveness of BNT162b2 vaccine against critical Covid-19 in adolescents.
      but, since current vaccines provide only limited short-term protection against infection or mild disease,
      • Powell A.A.
      • et al.
      Adolescent vaccination with BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine and effectiveness of the first dose against COVID-19: national test-negative case-control study, England.
      ,
      • Prunas O.
      • Weinberger D.M.
      • Pitzer V.E.
      • et al.
      Waning effectiveness of the BNT162b2 vaccine against infection in adolescents.
      the virus will likely continue to contribute indirect hospitalisations, just like other respiratory viruses. In conclusion, unlike adults, hospitalisation with a positive SARS-CoV-2 PCR-test is not a useful marker of severe COVID-19 in children. Our findings demonstrate that, not only do CYP have a very low risk of hospitalisation with SARS-CoV-2 infection, but the vast majority of hospitalised CYP (especially healthy CYP) with confirmed SARS-CoV-2 infection do not have severe COVID-19, irrespective of SARS-CoV-2 variant, while the minority with severe COVID-19 recovered without complications. The very low rate of severe COVID-19 during the omicron variant wave is also reassuring.

      Declaration of Competing Interest

      None.

      Funding

      None.

      Appendix. Supplementary materials

      References

        • Chappell H.
        • Patel R.
        • Driessens C.
        • et al.
        Immunocompromised children and young people are at no increased risk of severe COVID-19.
        J Infect. 2022; 84: 31-39
        • Castagnoli R.
        • Votto M.
        • Licari A.
        • et al.
        Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children and adolescents: a systematic review.
        JAMA Pediatr. 2020; 174: 882-889
        • Andrews N.
        • Tessier E.
        • Stowe J.
        • et al.
        Duration of protection against mild and severe disease by Covid-19 vaccines.
        N Engl J Med. 2022; 386: 340-350
        • Gurdasani D.
        • Bhatt S.
        • Costello A.
        • et al.
        Vaccinating adolescents against SARS-CoV-2 in England: a risk-benefit analysis.
        J R Soc Med. 2021; 114: 513-524
      1. UK Health Security Agency. Official Statistics: National flu and COVID-19 surveillance reports: 2021 to 2022 season. Available at: https://www.gov.uk/government/statistics/national-flu-and-covid-19-surveillance-reports-2021-to-2022-season (accessed 05 February 2022.

        • Taylor A.
        • Whittaker E.
        The changing epidemiology of respiratory viruses in children during the COVID-19 pandemic: a Canary in a COVID Time.
        Pediatr Infect Dis J. 2022; 41: e46-ee8
        • Ward J.L.
        • Harwood R.
        • Smith C.
        • et al.
        Risk factors for PICU admission and death among children and young people hospitalized with COVID-19 and PIMS-TS in England during the first pandemic year.
        Nat Med. 2022; 28: 193-200
        • Powell A.A.
        • et al.
        Adolescent vaccination with BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine and effectiveness of the first dose against COVID-19: national test-negative case-control study, England.
        MedRxiv. 2021; https://doi.org/10.1101/2021121021267408
        • Prunas O.
        • Weinberger D.M.
        • Pitzer V.E.
        • et al.
        Waning effectiveness of the BNT162b2 vaccine against infection in adolescents.
        medRxiv. 2022; https://doi.org/10.1101/2022.01.04.22268776
        • Olson S.M.
        • Newhams M.M.
        • Halasa N.B.
        • et al.
        Effectiveness of BNT162b2 vaccine against critical Covid-19 in adolescents.
        N Engl J Med. 2022; https://doi.org/10.1056/NEJMoa2117995