Comparison of the Clinical Features of SARS-CoV-2, Other Coronavirus and Influenza Infections in Infants Less Than 1-Year-Old

To the Editors:

We read with attention the review of Zimmerman and Curtis¹ on Coronavirus Disease 2019 (COVID-19) among children and take the opportunity of this letter to share additional information. Infection with severe acute respiratory syndrome coronavirus 2 has mostly been reported in adults, though a recent publication described 9 infants <1-year-old with COVID-19.² Among infant data are very few, though comparisons with infections due to other coronavirus strains will be helpful. The Pneumo-Study³ on the etiologic agents of pneumonia in children <5-year-old conducted by the Merieux Foundation Global Approach to Biological Research, Infectious diseases and Epidemics in Low-income countries (GABRIEL) network provides opportunities for comparisons.

We compared the published clinical features of hospitalized infants with COVID-19² and hospitalized infants infected with other coronavirus strains or influenza from the GABRIEL project. The incident case-control Pneumo-study was done in children less than 5 in low-/middle-income countries between 2010 and 2014. The protocol and initial results are detailed elsewhere.^3,4 The population was restricted to infants <1-year-old with features of pneumonia (ie, cases).³ Nasopharyngeal swabs were collected at admission to identify bacteria and viruses by reverse-transcription polymerase chain reaction (RT-PCR). Statistics were restricted to the same variables used by Wei et al² and to cases with positive swabs for a coronavirus or influenza virus.

Of the 333 infants with pneumonia, 17 had CoV-positive nasopharyngeal swabs [7 (41.2%) with HKU1, 5 (29.4%) with CoV OC43, 3 (17.7%) with CoV NL63, 2 (11.8%) with CoV 229E] and 31 had an influenza-positive swab [22 (71%) with Influenza A, 9 (29%) with Influenza B]. Cough seems less prevalent in COVID-19 compared with other infected infants (Table 1). While no deaths occurred in infants with COVID-19,² 3 infants infected with CoV in Pneumo-study died, 2 of whom were co-infected with Streptococcus pneumoniae.

TABLE 1.

Comparison of the Characteristics of Coronavirus Disease 2019, Other Coronavirus and Influenza Infections Among Infants < 1-yr-old

This report underscores the lack of major differences in the clinical features of severe acute respiratory syndrome coronavirus 2 and other types of CoV or influenza infections among infants despite limited clinical features reported. COVID-19 infection does not seem more severe than other CoV or influenza infections in this population, possibly as all infect Angiotensin-Converting Enzyme 2 receptors in the upper airways. As influenza,⁵ the contribution of infants to the spread COVID-19 should be investigated. S. pneumoniae was co-detected in the CoV-infected infants who died in Pneumo-study while bacterial co-detection was not reported by Wei et al.² Infants in both studies^2,3 were hospitalized limiting selection bias but small sample sizes weakened statistical power. The incidence of COVID-19 in infants less than 1-year-old is currently low, but studies are needed to describe the clinical features, prognosis and impact of infected infants on the COVID-19 spread.

ACKNOWLEDGMENTS

*Pneumonia Study GABRIEL members: Gláucia Paranhos-Baccalà, Shally Awasthi, Mélina Messaoudi Ashish Bavdekar, Jianwei Wang, Lili Ren, Sonali Sanghavi, Souleymane Diallo, Monidarin Chou, Tekchheng Eap, Mala Rakoto-Andrianarivelo, Muriel Maeder, Budragchaagiin Dash-Yandag, Wilma Basualdo, Pagbajabyn Nymadawa, Jean-William Pape, Vanessa Rouzier, Graciela Russomando, Mariam Sylla.

Philippe Vanhems, MD, PhD
Hospices Civils de Lyon et Centre
International de Recherche en Infectiologue
Lyon, France

Hubert Endtz, MD
Emerging Pathogens Laboratory,
Mérieux Foundation
Lyon, France and Medische Microbiologie en
Infectieziekten (MMIZ), Erasmus MC,
Rotterdam, The Netherlands

Cédric Dananché, DrPharm, PhD
Hospices Civils de Lyon et Centre
International de Recherche en Infectiologue
Lyon, France

Florence Komurian-Pradel, PhD
Valentina Sanchez Picot, DVM
Emerging Pathogens Laboratory
Mérieux Foundation
Lyon, France
For the Pneumonia Study GABRIEL members*