Swiss study indicates school-based transmission may not necessarily be cause for concern

The kids are all right — at least when it comes to being low-risk transmitters of SARS-CoV 2, according to researchers from Switzerland.

Out of 39 evaluable households, only 8% had a child as the suspected index case, with Covid-19 symptom onset preceding illness in adult household contacts (HHCs), reported Arnaud G. L’Huillier, MD, of Geneva University Hospitals and Medical School, and co-authors.

And in 79% of households, one or more adult family member “was suspected or confirmed for Covid-19 before symptom onset in the study child, confirming that children are infected mainly inside familial cluster,” they wrote in Pediatrics.

While the study had many limitations — the authors could not confirm that child-to-adult transmission occurred; the sample most likely didn’t capture the total number of pediatric SARS-CoV-2 cases during the study period; and HHC recall may have been inaccurate — they are meaningful “because of the extensive HHC tracing and the almost absence of loss to follow-up,” stated L’Huillier’s group.

The results will undoubtedly add fuel to the fire in the “Should they or shouldn’t they?” debate over school re-openings. In the U.S., groups such as the CDC and American Academy of Pediatrics have released re-opening guidance. However, the Trump administration has criticized, or outright dismissed, those recommendations, and aggressively pushed for schools to re-start, including dubious threats to cut federal school funding if they don’t.

A July 11 New York Times report revealed that, based on internal documents, CDC officials deem full school reopening of K-12 and universities as “the highest risk” for the spread of coronavirus.

Politics aside, the current findings shed more light on the ways in 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,” noted William V. Raszka, Jr., and Benjamin Lee, MD, both of the Larner College of Medicine at the University of Vermont in Burlington, in a commentary accompanying the study.

Putting the current study results in context with other research, with similar findings, out of China, France, Australia, and Ireland, they offer “early reassurance that school-based transmission could be a manageable problem, and school closures may not have to be a foregone conclusion, particularly for elementary school-aged children who appear to be at the lowest risk of infection,” Raszka and Lee stated.

The authors identified all patients ages <16 years in the Geneva University Hospital surveillance network from March 10 to April 10, 2020. Chart reviews were used to obtain clinical data, and parents were called for patients and HHC follow-up.

“HHCs were considered suspect if they had fever or acute respiratory symptoms, as per the Swiss Federal Office for Public Health’s case definition,” they explained.

Among 4,310 patients with SARS-CoV-2, 0.9% met the study’s entry criteria. The median household follow-up was 18 days. The children’s median age was 11.1 years, and 56% were female. The most commonly reported symptom was cough (82% of kids) and most were diagnosed with an upper respiratory tract infection (69%).

However, the authors pointed out that “headache and nasal discharge were described in more than half of cases, and anosmia and abdominal symptoms were described in <20%, which is more frequent than previously described” by the CDC. Raszka and Lee noted that there have been more recent reports of “a novel Kawasaki disease-like multisystem inflammatory syndrome” in pediatric patients with COVID-19.

L’Huillier and co-authors reported that 74% of the pediatric patients were previously healthy, and that the most frequently reported comorbidity was asthma (10%). They also found that 85% of adult HHCs developed symptoms at some juncture versus 43% of pediatric HHCs (P<0.001). Additionally, 92% of mothers developed symptoms versus 75% of fathers (P=0.04).

They also found that “Surprisingly, in 33% of households, symptomatic HHCs tested negative despite belonging to a familial cluster with confirmed SARS-CoV-2 cases, suggesting an underreporting of cases.”

The authors concluded that “Extended diagnostic screening of suspected cases and thorough contact tracing are needed to better understand the dynamics of transmission within households,” while the Raszka and Lee urged that “serious consideration should be paid toward strategies that allow schools to remain open, even during periods of Covid-19 spread.”

Of course, that may be easier said than done, as school officials, parents, and teachers grapple with yet-to-be answered questions about safe reopening, such as accommodations for high-risk teachers or students, the enforcement of physical distancing, especially among very young children, and funding for masks and other safety equipment.

  1. In a Swiss study of 39 households, only 8% had a child as the suspected index case, with Covid-19 symptom onset preceding illness in adult household contacts.
  2. Along with other research, the findings offer early reassurance that school-based transmission could be a manageable problem, especially for elementary school-aged children who appear to be at the lowest risk of infection.

Shalmali Pal, Contributing Writer, BreakingMED™

L’Huillier and co-authors, as well as Raszka and Lee, reported no relationships relevant to the contents of this paper to disclose.


Cat ID: 125

Topic ID: 79,125,254,930,570,125,190,926,138,192,927,151,928,925,934