Skip to main content

Main menu

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • ERS Guidelines
  • Authors/reviewers
    • Instructions for authors
    • Submit a manuscript
    • Open access
    • Peer reviewer login
  • Alerts
  • Subscriptions
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

User menu

  • Log in
  • Subscribe
  • Contact Us
  • My Cart

Search

  • Advanced search
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

Login

European Respiratory Society

Advanced Search

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • ERS Guidelines
  • Authors/reviewers
    • Instructions for authors
    • Submit a manuscript
    • Open access
    • Peer reviewer login
  • Alerts
  • Subscriptions

What do differences in case fatality ratios between children and adults tell us about COVID-19?

Stefan Ebmeier, Aubrey J. Cunnington
European Respiratory Journal 2020 56: 2001601; DOI: 10.1183/13993003.01601-2020
Stefan Ebmeier
Section of Paediatric Infectious Disease, St Mary's Campus Medical School Building, Imperial College London, London, UK
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Stefan Ebmeier
Aubrey J. Cunnington
Section of Paediatric Infectious Disease, St Mary's Campus Medical School Building, Imperial College London, London, UK
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: a.cunnington@imperial.ac.uk
  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading

Abstract

When individuals without prior immunity are considered, case fatality ratios are typically higher in adults than in children for most infectious diseases, with few exceptions https://bit.ly/2Wsi6iJ

To the Editor:

Cristiani et al. [1] have raised interesting questions in their editorial discussing the differences in coronavirus disease 2019 (COVID-19) morbidity and mortality between children and adults. The authors proposed a number of possible reasons to explain why children suffer less severe illness, including age-related variation in angiotensin-converting enzyme (ACE)2 receptor expression, trained immunity, and differences in lymphocyte and natural killer cell abundance. Whilst these hypotheses may be correct, we wish to challenge the notion that greater morbidity and mortality in adults is a remarkable feature of COVID-19. This is, in fact, the typical situation for most infections occurring in the absence of prior immunity.

The novel COVID-19 virus emerged into a previously unexposed and presumably fully susceptible population at the end of 2019, facilitating its rapid spread around the world. It has since been well documented that children with COVID-19 suffer a milder illness than adults, with better clinical outcomes overall. Age-specific case fatality ratios appear to increase continuously from close to 0% in children aged <10 years to ∼13% in adults aged ≥80 years [2]. Globally, children suffer the greatest burden of most infectious diseases, particularly respiratory infections; hence, the low burden of COVID-19 in children has been viewed by many as surprising.

However, for most common infectious diseases, the relationships between age and disease severity are influenced by acquisition of immunity, and because immunity is dependent on exposure it therefore increases with age. When only susceptible individuals are considered, age-specific mortality rates are typically higher in adults than in children for most infectious diseases. This was observed for measles in historical first-contact island epidemics [3], and more recently for emerging infectious diseases including severe acute respiratory syndrome (SARS) [4], West Nile virus infection [5], and severe fever with thrombocytopenia syndrome (SFTS) [6]. Similar relationships are clear even for common infections causing their greatest burden in childhood, such as primary varicella infection [7] and Plasmodium falciparum malaria [8], when individuals without prior immunity are considered. We believe that the greater burden of COVID-19 in adults primarily reflects the fact that the whole population is susceptible, rather than an unusual association between severity and age.

Until we have better epidemiological data to be certain about denominators (numbers of infections in different age groups), it will be difficult to discern whether the relationship between age and case fatality ratio is monotonic or “J” shaped (with a higher case fatality ratio in the very youngest children compared with older children). However, comparisons between different age groups may tell us more about age-related host–pathogen interactions in general, than about the pathogenesis of COVID-19 specifically.

Shareable PDF

Supplementary Material

This one-page PDF can be shared freely online.

Shareable PDF ERJ-01601-2020.Shareable

Footnotes

  • Conflict of interest: S. Ebmeier has nothing to disclose.

  • Conflict of interest: A.J. Cunnington has nothing to disclose.

  • Received May 5, 2020.
  • Accepted May 8, 2020.
  • Copyright ©ERS 2020
http://creativecommons.org/licenses/by-nc/4.0/

This version is distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.

References

  1. ↵
    1. Cristiani L,
    2. Mancino E,
    3. Matera L, et al.
    Will children reveal their secret? The coronavirus dilemma. Eur Respir J 2020; 55: 2000749. doi:10.1183/13993003.00749-2020
    OpenUrlAbstract/FREE Full Text
  2. ↵
    1. Verity R,
    2. Okell LC,
    3. Dorigatti I, et al.
    Estimates of the severity of coronavirus disease 2019: a model-based analysis. Lancet Infect Dis 2020; 20: 669–677. doi:10.1016/S1473-3099(20)30243-7
    OpenUrlCrossRefPubMed
  3. ↵
    1. Shanks GD,
    2. Waller M,
    3. Briem H, et al.
    Age-specific measles mortality during the late 19th–early 20th centuries. Epidemiol Infect 2015; 143: 3434–3441. doi:10.1017/S0950268815000631
    OpenUrl
  4. ↵
    1. Jia N,
    2. Feng D,
    3. Fang LQ, et al.
    Case fatality of SARS in mainland China and associated risk factors. Trop Med Int Health 2009; 14: Suppl. 1, 21–27. doi:10.1111/j.1365-3156.2008.02147.x
    OpenUrl
  5. ↵
    1. Lindsey NP,
    2. Staples JE,
    3. Lehman JA, et al.
    Surveillance for human West Nile virus disease – United States, 1999–2008. MMWR Surveill Summ 2010; 59: 1–17.
    OpenUrlPubMed
  6. ↵
    1. Li H,
    2. Lu QB,
    3. Xing B, et al.
    Epidemiological and clinical features of laboratory-diagnosed severe fever with thrombocytopenia syndrome in China, 2011–17: a prospective observational study. Lancet Infect Dis 2018; 18: 1127–1137. doi:10.1016/S1473-3099(18)30293-7
    OpenUrl
  7. ↵
    1. Brisson M,
    2. Edmunds WJ
    . Epidemiology of varicella-zoster virus in England and Wales. J Med Virol 2003; 70: Suppl. 1, S9–S14. doi:10.1002/jmv.10313
    OpenUrlCrossRefPubMed
  8. ↵
    1. Checkley AM,
    2. Smith A,
    3. Smith V, et al.
    Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: an observational study. BMJ 2012; 344: e2116. doi:10.1136/bmj.e2116
    OpenUrlAbstract/FREE Full Text
PreviousNext
Back to top
View this article with LENS
Vol 56 Issue 1 Table of Contents
European Respiratory Journal: 56 (1)
  • Table of Contents
  • Index by author
Email

Thank you for your interest in spreading the word on European Respiratory Society .

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
What do differences in case fatality ratios between children and adults tell us about COVID-19?
(Your Name) has sent you a message from European Respiratory Society
(Your Name) thought you would like to see the European Respiratory Society web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Print
Citation Tools
What do differences in case fatality ratios between children and adults tell us about COVID-19?
Stefan Ebmeier, Aubrey J. Cunnington
European Respiratory Journal Jul 2020, 56 (1) 2001601; DOI: 10.1183/13993003.01601-2020

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero

Share
What do differences in case fatality ratios between children and adults tell us about COVID-19?
Stefan Ebmeier, Aubrey J. Cunnington
European Respiratory Journal Jul 2020, 56 (1) 2001601; DOI: 10.1183/13993003.01601-2020
del.icio.us logo Digg logo Reddit logo Technorati logo Twitter logo CiteULike logo Connotea logo Facebook logo Google logo Mendeley logo
Full Text (PDF)

Jump To

  • Article
    • Abstract
    • Shareable PDF
    • Footnotes
    • References
  • Figures & Data
  • Info & Metrics
  • PDF
  • Tweet Widget
  • Facebook Like
  • Google Plus One

More in this TOC Section

Agora

  • Airway immune responses to COVID-19 vaccination in COPD patients
  • Wider access to rifapentine-based regimens is needed for TB care globally
  • Association between immunosuppressants and outcomes of COVID-19
Show more Agora

Correspondence

  • Endothelial to mesenchymal transition as novel feature of pulmonary fibrosis
  • Transitioning endothelial cells contribute to pulmonary fibrosis
  • Treatable traits in ILD: why not consider acute exacerbations?
Show more Correspondence

Related Articles

Navigate

  • Home
  • Current issue
  • Archive

About the ERJ

  • Journal information
  • Editorial board
  • Press
  • Permissions and reprints
  • Advertising

The European Respiratory Society

  • Society home
  • myERS
  • Privacy policy
  • Accessibility

ERS publications

  • European Respiratory Journal
  • ERJ Open Research
  • European Respiratory Review
  • Breathe
  • ERS books online
  • ERS Bookshop

Help

  • Feedback

For authors

  • Instructions for authors
  • Publication ethics and malpractice
  • Submit a manuscript

For readers

  • Alerts
  • Subjects
  • Podcasts
  • RSS

Subscriptions

  • Accessing the ERS publications

Contact us

European Respiratory Society
442 Glossop Road
Sheffield S10 2PX
United Kingdom
Tel: +44 114 2672860
Email: journals@ersnet.org

ISSN

Print ISSN:  0903-1936
Online ISSN: 1399-3003

Copyright © 2023 by the European Respiratory Society