Summary of findings 4. Summary of findings: multicomponent measures.

Outcome	Number of studies	Summary of findings	Certainty of evidence
Outcome category: transmission‐related outcomes
Number or proportion of cases	2 observational/experimental studies (Isphording 2020; Vlachos 2020)	These two studies showed mixed results on the effectiveness of multicomponent interventions to make contacts safer on the number or proportion of cases. One study found that the intervention reduced cumulative infection rate by 0.55 or 27% of a standard deviation (Isphording 2020), while the other found that exposure to open rather than closed schools resulted in a small to moderate increase in the number of infections among parents and teachers, and their partners (Vlachos 2020).	Lowa,b ⨁⨁◯◯
Number or proportion of cases	1 modelling study (Naimark 2020)	One study compared a multicomponent intervention consisting of: i) reducing the number of students; ii) reducing the number of contacts; iii) universal masking; iv) alternating attendance schedules in high schools; and v) symptom‐based isolation, to full school closures. The study found that there was an increase in the predicted number of infections when reopening with measures compared to a full school closure scenario.	Very lowc,d,e ⨁◯◯◯

^aDowngraded ‐1 for risk of bias due to ROBINS‐I rating being moderate.
^bDowngraded ‐1 for inconsistency due to inconsistent effects in studies contributing to the outcome.
^cDowngraded ‐1 for risk of bias due to major concerns about the structural assumptions and input parameters.
^dDowngraded ‐1 for inconsistency due to only one study contributing to the outcome.
^eDowngraded ‐1 for imprecision due to only one study contributing to the outcome.