Skip to main content

Culture-Competent SARS-CoV-2 in Nasopharynx of Symptomatic Neonates, Children, and Adolescents

Our take —

This study assessed children testing positive for SARS-CoV-2 infection at the Geneva University Hospitals from January 25 to March 31, 2020. Among 23 who tested positive, 12 (52%) samples had SARS-CoV-2 virus that could be isolated and amplified in viral culture. The clinical and sociodemographic characteristics of children testing positive did not differ between those with and without isolated specimens, though viral load was associated with isolation. This research suggests that children can shed the SARS-CoV-2 virus, which is important for eventual transmission. A limitation is that this is an experimental setting using samples collected in routine medical care that may have degraded by the time the study started. They also had a small number of children testing positive overall. Therefore, while these results have implications for potential transmission of COVID-19 among children, more research must be done to show this at the population-level as well as research with children who are asymptomatic.

Study design

Retrospective Cohort

Study population and setting

The study objective was to describe cultivable SARS-CoV-2 in the upper respiratory tract of children with COVID-19. Of 638 patients seen at either the Geneva University Hospitals emergency room or sent in from other facilities as part of Geneva University Hospitals’ function as a national reference laboratory for emerging diseases, from January 25 to March 31. Of these 638, 23 (3.6%) tested positive for SARS-CoV-2. Samples were collected a median of 2 days following symptom onset, and researchers assessed the viral load in these participants. The study team isolated the virus from 12 (52%) of these children to assess viability of SARS-CoV-2 in a culture.

Summary of Main Findings

The study found the median age of children was 12 years (range: 7 days old to 15.9 years old). The majority received a clinical diagnosis of upper respiratory tract infection, and most were not admitted to the hospital. Only 2 children were diagnosed with a fever (8.7% of 23) and another 2 were diagnosed with pneumonia. The median viral load was higher for patients who had SARS-CoV-2 isolation compared to those without isolation. Sex, age, clinical diagnosis, symptoms, or hospital admission did not differ between patients by viral isolation.

Study Strengths

The study assessed SARS-CoV-2 viral load and isolation among participants with a range of symptom severity, showing the biological viability of SARS-CoV-2 among patients. They had a wide age range of participants, showing this potential effect not only in neonates but up to adolescents. By testing culture isolation among those who tested positive, the study is able to compare successful vs. unsuccessful isolation of samples with a robust comparison group, as opposed to if they had used the entire study sample for comparison.


A major limitation is that this was a retrospective cohort that used specimens obtained in routine medical care, which may have degraded between collection and initiation of the study. The study also only examined children presenting at the hospital who had these specimens taken or whose samples were sent in to the laboratory, which likely reflects only symptomatic cases and may also have selection bias for the cases with mild symptoms with a volunteer bias from those parents concerned enough about COVID-19 to come to the hospital. The study did not break down how many came from Geneva University Hospitals emergency room or how many were from other facilities who sent samples in for testing by the national reference laboratory. There were a small number of children who tested positive overall, and therefore there were statistical limitations in their power to detect differences between groups. Also, the study has important implications for potential transmission, but does not demonstrate viral transmission within the population, only a biological plausibility given their experiments.

Value added

This study shows that SARS-CoV-2 samples from children can be isolated in a culture, which could potentially lead to transmission in the population.

This review was posted on: 21 July 2020