Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

Investigations of cases identified in school settings suggest that child to child transmission in schools is uncommon and not the primary cause of SARS-CoV-2 infection in children whose onset of infection coincides with the period during which they are attending school, particularly in preschools and primary schools.

What is the evidence of transmission between children within the school setting?

Available evidence appears to suggest that transmission among children in schools is less efficient for SARS-CoV-2
than for other respiratory viruses such as influenza [82]. However, this evidence is mainly derived from school
outbreaks which tend to rely on detecting symptomatic cases only and will therefore underestimate the number of
infected, asymptomatic, and potentially infectious children in these outbreaks.

In France, a carefully documented study identified an infected child (age nine years) who had interactions with a
large number of contacts in three different schools and did not transmit the disease, as evidenced by the large
number of negative results of tested symptomatic and asymptomatic contacts [83].

In Ireland, transmission within schools was investigated prior to school closures and no evidence of secondary
transmission within the school setting was found. Among the 924 child contacts and 101 adult contacts of the six
cases (three children, three adults) in the school setting, there were no confirmed cases identified during the 14-
day follow-up period [84]. It is important to note that this study did not consider asymptomatic infections.

In Finland, no secondary cases were identified in contact tracing and testing of 89 out of 121 contacts of a 12-year
case who had attended school during their illness [85].

In Australia, a contact tracing study in 15 primary and high schools, where nine student COVID-19 cases were
detected, found one secondary positive case in a primary school student (out of 735 close child contacts who were
followed up) [86].

In Singapore, two preschools and one secondary school identified child index cases and tested close contacts. In a
case where a preschool child was the index case (mean age 4.9 years), 34 preschool student contacts developed potential COVID-19 symptoms during the incubation period, however all 34 symptomatic cases tested negative for
SARS-CoV-2. In a case where the index child was in secondary school (mean age 12.8 years), a total of eight out
of 77 students developed symptoms and were screened for SARS-CoV-2 during the incubation period. All eight
symptomatic student contacts from the school tested negative [87,88].

In Israel, a first large school outbreak emerged ten days after re-opening all schools with requirement for daily
health reports, hygiene, face masks, social distancing and minimal interaction between classes. The first two cases
were registered on 26 May and 27 May, having no epidemiological link. Testing of the complete school community
revealed 153 students (attack rate: 13.2%) and 25 staff members (attack rate: 16.6%) who were COVID-19
positive. Overall, some 260 persons were infected (students, staff members, relatives and friends) [88].
In summary, in children where COVID-19 was detected and contacts followed-up, only one child contact in the
school setting was detected as SARS-CoV-2 positive during the follow-up period. The conclusion from these
investigations is that child-to-child transmission in schools is uncommon and not the primary cause of SARS-CoV-2
infection of children whose infection onset coincides with the period during which they are attending school.