From the Journals

Children rarely transmit SARS-CoV-2 within households



Children appear less likely than adults to be the first cases of COVID-19 within a household, based on data from families of 39 children younger than 16 years.

Transmission electron micrograph of SARS-CoV-2 virus particles Courtesy NIAID

“Unlike with other viral respiratory infections, children do not seem to be a major vector of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, with most pediatric cases described inside familial clusters and no documentation of child-to-child or child-to-adult transmission,” said Klara M. Posfay-Barbe, MD, of the University of Geneva, Switzerland, and colleagues.

In a study published in Pediatrics, the researchers analyzed data from all COVID-19 patients younger than 16 years who were identified between March 10, 2020, and April 10, 2020, through a hospital surveillance network. Parents and household contacts were called for contact tracing.

In 31 of 39 (79%) households, at least one adult family member had a suspected or confirmed SARS-CoV-2 infection before onset of symptoms in the child. These findings support data from previous studies suggesting that children mainly become infected from adult family members rather than transmitting the virus to them, the researchers said

In only 3 of 39 (8%) households was the study child the first to develop symptoms. “Surprisingly, in 33% of households, symptomatic HHCs [household contacts] tested negative despite belonging to a familial cluster with confirmed SARS-CoV-2 cases, suggesting an underreporting of cases,” Dr. Posfay-Barbe and associates noted.

The findings were limited by several factors including potential underreporting of cases because those with mild or atypical presentations may not have sought medical care, and the inability to confirm child-to-adult transmission. The results were strengthened by the extensive contact tracing and very few individuals lost to follow-up, they said; however, more diagnostic screening and contact tracing are needed to improve understanding of household transmission of SARS-CoV-2, they concluded.

Resolving the issue of how much children contribute to transmission of SARS-CoV-2 is essential to making informed decisions about public health, including how to structure schools and child-care facility reopening, Benjamin Lee, MD, and William V. Raszka Jr., MD, both of the University of Vermont, Burlington, said in an accompanying editorial (Pediatrics. 2020 Jul 10. doi: 10.1542/peds/2020-004879).

The data in the current study support other studies of transmission among household contacts in China suggesting that, in most cases of childhood infections, “the child was not the source of infection and that children most frequently acquire COVID-19 from adults, rather than transmitting it to them,” they wrote.

In addition, the limited data on transmission of SARS-CoV-2 by children outside of the household show few cases of secondary infection from children identified with SARS-CoV-2 in school settings in studies from France and Australia, Dr. Lee and Dr. Raszka noted.

“On the basis of these data, SARS-CoV2 transmission in schools may be less important in community transmission than initially feared,” the editorialists wrote. “This would be another manner by which SARS-CoV2 differs drastically from influenza, for which school-based transmission is well recognized as a significant driver of epidemic disease and forms the basis for most evidence regarding school closures as public health strategy.”

“Therefore, serious consideration should be paid toward strategies that allow schools to remain open, even during periods of COVID-19 spread,” the editorialists concluded. “In doing so, we could minimize the potentially profound adverse social, developmental, and health costs that our children will continue to suffer until an effective treatment or vaccine can be developed and distributed or, failing that, until we reach herd immunity,” Dr. Lee and Dr. Raszka emphasized.

The study received no outside funding. The researchers and editorialists had no financial conflicts to disclose.

SOURCE: Posfay-Barbe KM et al. Pediatrics. 2020 Jul 10. doi: 10.1542/peds.2020-1576.

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