· The terms cluster and outbreak both describe the occurrence of new disease cases within a particular location and time period. The number of cases within a cluster are not necessarily greater than what is expected, however in an outbreak the number of cases does exceed the usual norm.
· In an outbreak the cases are confirmed to be epidemiologically linked while in a cluster an epidemiological connection is only suspected.
· Not all clusters are outbreaks, however each cluster needs to be investigated
· Understanding how to characterize COVID-19 cases based on a suspected or proven epidemiological link can better guide prevention of disease spreading
Radu, L; Badea, A; Groot, G; Ellsworth, C; Young, C. What is the definition of an outbreak versus a cluster for COVID-19 in different clinical and community settings in Canada, the US, and the UK? 2020 Jul 27; Document no.: EOC071001 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 11 p. (CEST rapid review report)
A number of jurisdictions have re-opened schools successfully without a spike in COVID-19 cases, eg. Japan, Germany, France, Finland, Denmark, Austria, Norway
Most school plans indicate that staff/students/visitors who are sick or have had exposure to COVID-19 in the past 14 days should not attend school, and those that become symptomatic at school should be isolated and removed from the premises as soon as possible, with thorough cleaning thereafter
In Alberta, if two or more members of a cohort are found to be COVID-19 positive, schools should follow the outbreak procedures which are under review until September
In Nova Scotia, one confirmed case of COVID-19 in a school would be considered an outbreak
In Germany, classmates and teachers of an infected student are sent home for two weeks but other classes continue
Taiwan (based on the H1N1 response) suspends the class which had a confirmed case identified, for 14 days. With two or more cases the whole school must close. When 1/3 of the schools in a district are closed, all schools in the district must close.
In Israel, schools closed after a single case was identified , and following mass outbreaks in schools at least 355 schools had closed with over 2,026 students and staff testing positive and over 28,000 students in quarantine due to possible exposure
Badea, A; Muhajarine, N; Reeder, B; Miller, L; Mueller, M. What is the evidence and rationale describing the key public health principles to consider for school re-openings and precautions regarding school closures during COVID-19? 2020 Aug 17; Document no.: EOC070901 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 22 p. (CEST rapid review report)
Based on a rapid review performed by the Public Health Agency of Canada and an updated literature search found herein, there is limited evidence of SARS-CoV-2 viral transmission through heating, ventilation, and air conditioning (HVAC) systems.
Schools are encouraged to ensure their HVAC systems are functioning properly in order to further mitigate risk of viral spread via this method.
Recommendations for optimal HVAC system settings are published, but schools should follow local guidelines with the help of HVAC professionals.
Vanstone, J; Asamoah, G; Muhajarine, N; Reeder. B; Dalidowicz, M; Young, C. What role do ventilation systems play in the prevention and spread of COVID-19 and other respiratory diseases in non-clinical buildings? 2020 Sep 4; Document no.: EOC082501 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 7 p. (CEST rapid review report)
Badea, A; Groot, G; Howell-Spooner, B; Young, C. What is the evidence for the effectiveness of universal mask use by the public? 2020 Dec 1; Document no.: EOC062301v3 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 33 p. (CEST rapid review report)
Studies conducted before mass vaccination campaigns began have reported proper and consistent facemasking by students and staff in school settings are associated with reduced incidence of school-associated transmission or seropositivity.
Fewer studies have reported efficacy of facemasking in the post-mass vaccination period in school settings. The studies available report, however, school-associated transmission were lower, less than 1% secondary attack rate in schools.
Studies of school-associated COVID-19 cases find community exposure to SARS-CoV-2 and/or noncompliance with multiple mitigation measures (e.g. facemask policies, distancing, non-isolation, etc) are key factors of clusters and outbreaks in children.
Badea, A; Groot, G; Muhajarine, N; Howell-Spooner, B; Young, C. What is the evidence for the effectiveness of universal mask use in the pediatric population? 2021 Sep 30, Document no.: EOC210901 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 14 p. (CEST rapid review report).
Rowein S, Singh S, Habbick M, Mehdiyeva K, Miller L, Gagneur, A, Groot G, Neudorf C, Camillo CA, Tokhmafshan, F, Muhajarine N. Motivational Interviewing for Vaccine Hesitancy. May 2022. Document no.: [12.1]. CoVaRR-Net Public Health, Health Systems, Social Policy Team, c2022.