Table 9.

Quality assessment using the Newcastle-Ottawa Scale for cohort studies

Study ID	Selection Bias				Comparability		Detection Bias		Attrition Bias
	Representativeness of exposed group	Representativeness of unexposed group	Ascertainment of exposure	Outcome not present at start of study	Matching for school mitigation policies	Matching for age	Assessment of SARS-CoV-2	Confirmation of SARS-CoV-2	Adequacy of length of follow-up	Loss-to-follow-up rate
Danis 2020 [17]	*	*	*	NR	*	*	NR	NR	*	NR
Heavey 2020 [18]	*	*	NR	NR	*	*	NR	NR	*	NR
Yung 2020 [19]	*	*	*	NR	*	*	NR	*	*	NR
NCIRS 2020 [20]	*	*	*	NR	*	*	NR	NR	*	NR
Macartney 2020 [21]	*	*	*	NR	*	*	NR	NR	*	NR

* – denotes that the study met the criteria; NR – denotes either that the study did not meet criteria or that it was not reported