RESUMO
BackgroundWe aimed to quantify the risk of transmission of SARS-CoV-2 in the school setting by type of school, characteristics of the index case and calendar period in the Reggio Emilia province (RE), Italy. The secondary aim was to estimate the promptness of contact tracing. MethodsA population-based analysis of surveillance data of all COVID-19 cases occurring in RE, Italy, from September 1, 2020, to April 4th, 2021, for which a school contact and/or exposure was suspected. Indicator of the delay in contact tracing was computed as the time elapsed since positivity of the index case and the date on which the swab for classmates was scheduled (or most were scheduled). ResultsOverall, 30,184 and 13,608 contacts among classmates and teachers/staff, respectively, were identified and received recommendation for testing; 43,214 (98.7%) performed the test. Secondary transmission occurred in about 40% of the investigated classes, and the overall secondary case attack rate was 4%, slightly higher when the index case was a teacher, but with almost no differences by type of school and stable during the study period. Promptness of contact tracing increased during the study period, reducing the time from index case identification and testing of contacts from 7 to 3 days, as well the ability to identify possible source of infection in the index case. ConclusionsDespite the spread of the Alpha variant during the study period in RE, the secondary case attack rate remained stable from school reopening in September 2020 until the beginning of April 2021.
RESUMO
BackgroundSchool closures was one of the main measures undertaken to reduce the number of social contacts during the first wave of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. We aimed to describe the data on secondary transmission of SARS-CoV-2 among students and teachers/personnel after the reopening of preschools and schools in Reggio Emilia, Italy. MethodsThis prospective population-based study included all consecutive cases leading to an investigation in 41 classes of 36 educational institutions (8 infant-toddler centres and preschools, 10 primary and 18 secondary schools) in the period September 1 - October 15, 2020, in Reggio Emilia province, Italy. We report the characteristics of the school, of the index case, including the possible source of infection, the number of contacts (students and teachers/personnel) that were identified and tested and the characteristics of secondary cases. ResultsIn the study period, 994 students and 204 teachers were tested during related investigations due to notification of 43 primary cases (38 among students and 5 among teachers). Of these, 10 students and two teachers created 39 secondary cases, resulting in an attack rate of 3.9%. There were no secondary cases among teachers/stuff. Secondary transmission occurred in one primary school and 8 secondary schools. Except for two students and one teacher, the possible source of infection for all index cases was identified as they had all had previous contact with a positive case; the majority of secondary cases did not report any previous close contact with a positive case. The clusters ranged from one to 22 secondary cases. ConclusionsTransmission at school occurred in a non-negligible number of cases, particularly in secondary schools. Prompt testing and isolation of classmates could probably reduce the risk of transmission in school settings.
