Viral shedding lasted several weeks in some infected children

In a study among the first to systematically examine the frequency of asymptomatic infections in children and the duration of symptoms and viral shedding in both asymptomatic and symptomatic children with Covid-19, researchers reported on 91 children younger than 19-years of age with a Covid-19 diagnosis. They found that two-thirds (66.2%) had unrecognized symptoms before their diagnosis and just 1-in-4 (25.4%) developed symptoms after being diagnosed. Just over 1-in-5 (22%) cases were asymptomatic.

Among the 71 children who developed symptoms, the median duration of symptoms was 11 days, with a wide duration range of 1 day to 36 days. Additionally, the mean duration of SARS-CoV-2 infection in upper respiratory samples was 17.6 days, and virus was detected for a mean of 14.1 days in children and adolescents who were asymptomatic. Children who were pre-symptomatic at diagnosis had the shortest median symptom duration (3.5 days [1-21 days], with those who were symptomatic at the time of diagnosis had the longest (median, 13 days [3-36 days]. Although the majority of symptomatic children (41 of 71 [58%]) had upper respiratory tract disease, there was no difference in the duration of symptoms between those with upper vs mild or moderate lower respiratory tract infection. This suggests that even mild and moderately affected children remain symptomatic for long periods of time.

Writing in the journal JAMA Pediatrics, published online August 28, researcher Mi Seon Han, MD, PhD, of Seoul National University Boramae Medical Center, and colleagues, wrote that while the detection of viral RNA does not necessarily confirm the presence of viable virus, if proven infectious “the transmission potential of SARS-CoV-2 in children and its effect on the community might be greater than expected.”

In an editorial published with the study, Roberta DeBiasi, MD, and Meghan Delaney, DO, of Children’s National Hospital and Research Institute, Washington DC, wrote that the inclusion of children with Covid-19 who were asymptomatic, presymptomatic, and symptomatic was a significant study strength.

The finding that only a small percentage of the children were identified as infected through testing done concurrently with symptom onset “highlights the concept that infected children may be more likely to go unnoticed either with or without symptoms and continue on with their usual activities, which may contribute to viral circulation within their community,” they wrote.

They noted that the study finding regarding asymptomatic children “aligns with adult data in which up to 40% of adults may remain asymptomatic in the face of infection.”

“Fully half of symptomatic children with both upper and lower tract disease were still shedding virus at 21 days,” they wrote. “These are striking data,” they added, given that 98% either had no symptoms or mild or moderate disease[…] These findings are highly relevant to the development of public health strategies to mitigate and contain spread within communities, particularly as affected communities begin their recovery phases,” they concluded.

Respiratory vs Gastrointestinal Viral Shedding

In a systematic review and synthesis of data, recently published in the Pediatric Infectious Disease Journal, Dr. Cecilia L H Xu and colleagues sought to determine the average shedding times of SARS-CoV-2 via both the respiratory and gastrointestinal tracts in children.

Of the children who underwent testing with stool PCR, rectal swab or anal swab, 86% returned a positive result. The mean duration of viral shedding via the gastrointestinal tract was 23.6 ± 8.8 days from symptom onset. In 89% of cases, viral shedding via the gastrointestinal tract persisted after nasopharyngeal or throat swabs became negative, for as long as 4 weeks.