Secondary Transmission of COVID-19 in Preschool and School Settings in Northern Italy After Their Reopening in September 2020: a Population-Based Study
Total Page:16
File Type:pdf, Size:1020Kb
Rapid communication Secondary transmission of COVID-19 in preschool and school settings in northern Italy after their reopening in September 2020: a population-based study Elisabetta Larosa¹ , Olivera Djuric2,3 , Mariateresa Cassinadri¹ , Silvia Cilloni¹ , Eufemia Bisaccia¹ , Massimo Vicentini² , Francesco Venturelli1,4 , Paolo Giorgi Rossi² , Patrizio Pezzotti⁵ , Emanuela Bedeschi¹ , the Reggio Emilia Covid-19 Working Group⁶ 1. Public Health Unit, Azienda Unità Sanitaria Locale – IRCCS di Reggio Emilia, Reggio Emilia, Italy 2. Epidemiology Unit, Azienda Unità Sanitaria Locale – IRCCS di Reggio Emilia, Reggio Emilia, Italy 3. Center for Environmental, Nutritional and Genetic Epidemiology (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Italy 4. Clinical and Experimental Medicine PhD Program, University of Modena and Reggio Emilia, Modena, Italy 5. Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy 6. The members of the Reggio Emilia Covid-19 Working Group are listed under Investigators Correspondence: Olivera Djuric ([email protected]) Investigators group: Reggio Emilia Covid-19 Working Group: Massimo Costantini, Paolo Giorgi Rossi, Roberto Grilli, Massimiliano Marino, Debora Formisano, Giulio Formoso, Emanuela Bedeschi, Cinzia Perilli, Ivano Venturi, Eufemia Bisaccia, Elisabetta Larosa, Mariateresa Cassinadri, Silvia Cilloni, Cinzia Campari, Francesco Gioia, Serena Broccoli, Marta Ottone, Pierpaolo Pattacini, Giulia Besutti, Valentina Iotti, Lucia Spaggiari, Pamela Mancuso, Andrea Nitrosi, Marco Foracchia, Rossana Colla, Alessandro Zerbini, Marco Massari, Anna Maria Ferrari, Mirco Pinotti, Nicola Facciolongo, Ivana Lattuada, Laura Trabucco, Stefano De Pietri, Giorgio Francesco Danelli, Laura Albertazzi, Enrica Bellesia, Simone Canovi, Mattia Corradini, Tommaso Fasano, Elena Magnani, Annalisa Pilia, Alessandra Polese, Silvia Storchi Incerti, Piera Zaldini, Efrem Bonelli, Bonanno Orsola, Matteo Revelli, Carlo Salvarani, Francesco Venturelli Citation style for this article: Larosa Elisabetta, Djuric Olivera, Cassinadri Mariateresa, Cilloni Silvia, Bisaccia Eufemia, Vicentini Massimo, Venturelli Francesco, Giorgi Rossi Paolo, Pezzotti Patrizio, Bedeschi Emanuela, the Reggio Emilia Covid-19 Working Group. Secondary transmission of COVID-19 in preschool and school settings in northern Italy after their reopening in September 2020: a population-based study. Euro Surveill. 2020;25(49):pii=2001911. https://doi.org/10.2807/1560-7917. ES.2020.25.49.2001911 Article submitted on 11 Nov 2020 / accepted on 10 Dec 2020 / published on 10 Dec 2020 We report epidemiological investigations of transmis- 15% fatality rate (0.2% for age < 50 years and 33.4% for sion of the severe acute respiratory syndrome coro- age > 80 years) [1,2]. After 5 months of low incidence, the navirus 2 (SARS-CoV-2) in 41 classes of 36 schools in province began the second wave in October (Figure). Reggio Emilia province, northern Italy, from their reo- pening on 1 September to 15 October 2020. The overall Ca 31,000 students aged 0–19 years are attending secondary case attack rate was 3.2%, reaching 6.6% educational institutions in the province: infant-toddler in middle and high schools. More timely isolation and centres (age 0–3 years), preschools (age 3–5 years), testing of classmates could be effective in reducing elementary schools (age 6–10 years), middle schools virus transmission in this setting. (age 11–13 years) and high schools (age 14–19 years). While infant-toddler centres and preschools reopened Schools in Reggio Emilia province, northern Italy, reo- after lockdown on 1 September and remedial courses pened on 1 September 2020 after a long period of were activated, the official reopening of all schools closure due to lockdown and summer holidays. We con- was on 15 September. ducted epidemiological investigations after reopen- ing in 41 classes in 36 different educational settings Physical distancing policies in schools in this province after the notification of an infection Upon reopening of all schools, the following physical with severe acute respiratory syndrome coronavirus 2 distancing measures were adopted (Supplementary (SARS-CoV-2). Table S1): mandatory wearing of surgical masks for chil- dren at all times except when students are seated at Current epidemiological features of their desk and are not speaking (except in preschools COVID-19 in Reggio Emilia province and or elementary schools where wearing the mask is never reopening of educational facilities mandatory); only single desks are used (rather than The first wave of the coronavirus disease (COVID-19) the traditional double desks), and desks must be at pandemic hit the Reggio Emilia province (northern Italy, least 1 m apart; crowding at separate school entrances 530,000 inhabitants) in March and April 2020, reach- and exits is minimised by creating temporal and spatial ing ca 0.9% cumulative incidence (0.4% for age < 50 pathways for the different classes; mixing classes for years and 3.2% for age > 80 years) with a more than curricular activities is minimised; all extra-curricular www.eurosurveillance.org 1 learning. groups, which alternate attending school remote and physical distancing, students are dividedtwo into when the classrooms are enough not big respect to are isolated the if physical classroom itself makes mates determines isolation measures: (i) students all of the contact between the index case their and class was performed. During the investigation, the nature daysthan 10 after the contact; usually only one test the index case the if first testwas performed more tested retested and 14 days after the last contact with who contact had with the index case are immediately schoolstudents staff, and/or classmates all staff and Health Authority. When acase identified is among reported the to Public Health Department of the Local All SARS-CoV-2-positive swabs are immediately ever occurred first (n or 48 haftersis the contact with acertain case, which onset for and asymptomatic cases 48 hbefore diagno tracing, the in period i.e. starting 48before h symptom attending schools the in period investigated for contact excluded We cases that occurred children not among assessed during the epidemiological investigation. years) who exposure possible had or contacts school in province adolescentsEmilia children and among (0–19 diagnosed fromOctoberSeptember 1 15 to Reggio in beto positive with RT-PCR for SARS-COV-2 infection, consecutive all included We COVID-19 cases, confirmed investigation Study period and epidemiological activities have been suspended [ disease. coronavirus COVID-19: 2020 November (n February–10 Daily number notified of cases and COVID-19 deaths since the start the of Reggio epidemic in Italy, Emilia province, 27 Figure 2 Number of cases 1 1 2 2 3 3 4 0 5 5 0 5 0 0 5 0 0 0 0 0 0 0 0 0 26 Feb c S l c 4 Mar o h s o u o r D D 11 Mar e l s e i a a g t n 18 Mar h o s i 25 Mar s = 134). 1 Apr 8 Apr 15 Apr 22 Apr = 11,878 cases, n 11,878 3 29 Apr ]. In some schools, 6 May 13 May 20 May 27 May = 3 Jun deaths) 658 10 Jun - - - 17 Jun D 24 Jun a t e 1 Jul 2 ing withing the other students has been respected. of school are isolated, provided that physical distanc only those close in contact or who contact have outside worn secondaryif constantly cases and/or occur; or (ii) maintaining masks distance impossible are and/or not ary cases the in preschools teachers/staff. or among mentary while there were no second schools (0.38%), than ele in highschools and schools) (6.6%) (middle rate of 3.2%. The attack rate was higher secondary in teachers among resultingmission overall an in attack high schools ( schoolstwo in and offive schools middle six and of13 theamong 994 tested elementary one of 10 in children: A total of 38 secondary cases (3.8%) were identified students teachers/staff). 204 and tacts were identified, of whom were 1,198 tested (994 During the epidemiological investigations, 1,200 con uals teachers/staff (209 ( 1,039 and children) atotal population including schools), of 1,248 individ elementary 18 secondary and high schools and (middle fied: eight infant-toddler centres preschools, and 10 In the study period, classes 41 36 in schools were noti Secondary attack rate have done; none denied consent. contact them, given that the all efforts contact to them the of consent absence it if would not to be possible Committee authorised use to patients’ data even in The Ethics Nord Ethics Committee 2020/0045199). (no. The study was approved by the Area Vasta Emilia Ethical statement 0 2 8 Jul 0 15 Jul 22 Jul R e 29 Jul m e d i 5 Aug a l c Table 2 Table o 12 Aug u r s e 19 Aug s o 26 Aug p ). There). was no secondary trans e n i 2 Sep n g 9 Sep S c S h 16 Sep t o u o d l s 23 Sep y o p p e r e 30 Sep i n o i d n 7 Oct g 14 Oct 21 Oct Table 1 Table 28 Oct 4 Nov ). - - - - - - - www.eurosurveillance.org Table 1 Characteristics of teaching/childcare facilities with identified COVID-19 cases and their pupils and personnel, Reggio Emilia province, Italy, 1 September–15 October 2020 (n = 1,248) Number Percentage Number of schools 36 Type of school Infant-toddler centre and preschool (0–5 years) 8 Elementary school (6–10 years) 10 Secondary school 18 Middle school (11–13 years) 5 High school (14–19 years) 13 Number of school classes 41 Index cases 48 Students 43 Teachers/staff 5 Number of contacts identified during investigations 1,200 100 Tested students 994 82.8 Students not tested 2 0.2 Tested teachers/staff 204 17.0 Secondary cases 38 3.2a Students 38 Teachers/staff 0 COVID-19: coronavirus disease.