A study posted to the medRxiv* preprint server examined the clinical manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, disease severity, and related hospitalization in infants in Canada.
Clinical characteristics and risk factors of coronavirus disease 2019 (COVID-19) in adults and older children have been well researched and reported throughout the course of the pandemic. However, research on COVID-19 characteristics in younger children and infants is sparse. So far, various reports describe infants to be at a higher risk of COVID-19 severity as compared to older children, while some reports, in contrast, detailed similar characteristics among all age groups.
About the study
The present study reported the characteristics of SARS-CoV-2, the severity of disease, and manifestations associated with COVID-19-related hospitalizations in COVID-19-infected infants in Canada. This national study used the data from the Canadian Paediatric Surveillance Program, which reported inpatients and outpatients in clinics as well as in emergency departments.
The study involved three groups of infant populations – those aged less than a year with SARS-CoV-2-related hospitalizations; children infected with acute COVID-19 but not hospitalized; and COVID-19-infected children hospitalized with non-COVID-19-related conditions. The researchers collected demographic data, epidemiology of the cases involved, laboratory and clinical manifestations, therapeutic measures, and outcomes of the cases selected for the study. These cases were detected during the different waves of the COVID-19 pandemic in Canada between March 2020 and June 2020; September 2020 and January 2021; and March 2021 and May 2021.
Infected infants were classified into neonates of the age of less than one month, infants aged between one to three months, between four to six months, and between seven to 12 months.
The severity of the disease was evaluated based on the World Health Organization (WHO) COVID-19 clinical characterization and management working group scale and classified into groups of asymptomatic, outpatient care, mild disease, moderate disease, and severe disease.
The study results showed that the median age of infants treated as outpatients was 160 days, while that of infants hospitalized for COVID-19 was 37 days. In total, 531 infants of ages less than a year old were reported between 8 April 2020 and 31 May 2021, among which 37.7% of patients were hospitalized while 62.5% were not hospitalized. Approximately 15% of the patients were neonates including 13 patients aged less than seven days old and 67 patients aged between eight to 28 days old. Around 58.5% of the patients had reported close contact with a SARS-CoV-2-positive patient. This was either the patient’s parents in 79.2% of the cases, a sibling in 14.7% of the cases, any other relative in 16.4% of the cases, or non-family members in 4.2% of the cases.
In the reported cases, 12.4% of infants showed SARS-CoV-2 symptoms, with fever being the most common symptom in 66.5% of the patients, followed by coryza in 47.1%, cough in 37.3%, and reduced oral intake in 25.0% of the patients. Upper respiratory tract infection (URTI) was the most common clinical syndrome found in 60.5% of the patients while gastrointestinal syndrome was present in 30.3% of the patients, bronchitis in 3.8% of the patients, and pneumonia in 2.6% of the patients. A total of 11.1% of the cases reported had at least one comorbidity including 3.8% of cases with congenital heart disease, 3.6% with a neurologic and neurodevelopmental disease, and 1.9% with chronic lung disease. More than one comorbidity was observed in 2.6% of infant cases.
In the group of hospitalized infants, COVID-19-related hospitalization was reported in 70.9% of the cases while 29.1% of the hospitalizations were related to non-COVID-19 conditions. An adjusted odds ratio (aOR) of 3.78 was observed for COVID-19-related hospitalizations of neonates while infants between the ages of four to six months and ages seven to 12 months had an aOR of 0.24 and 0.13, respectively. Patients with one or more comorbidities reported a higher chance of COVID-19-related hospitalizations as compared to patients with no known comorbidities.
Among COVID-19-related hospitalizations, 78.7% of the infants suffered from mild disease, 7.1% had moderate disease, and 14.2% suffered from severe disease. A total of 9.9% of the infants required intensive care unit (ICU) admission due to COVID-19 infection while less than five infants needed non-invasive ventilation and five infants needed mechanical ventilation. Respiratory support was required by 26.5% of neonates hospitalized for COVID-19-related conditions, while 11.0% of the hospitalized infants of ages between one to 12 months needed respiratory support.
The study findings show that cases of severe COVID-19 manifestations were less commonly reported in infants than in adults and adolescents.
However, neonates of ages below a month showed an increased risk of COVID-19-related hospitalization and also needed respiratory support more often than older infants required.
The lack of SARS-CoV-2 vaccines for infants and neonates necessitates the acceptance and administration of the vaccines in pregnant women to prevent infection in infants.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.