Epidemiological burden of parents being the index cases of COVID-19 infected children

Table 2 Risk of bias assessment using National Heart, Lung, and Blood Institute's tool[12]

Study design: Case series
Ref.				1. Was the study question or objective clearly stated?			2. Was the study population clearly and fully described, including a case definition?		3. Were the cases consecutive?		4. Were the subjects comparable?			5. Was the intervention clearly described?	6. Were the outcome measures clearly defined, valid, reliable, and implemented consistently across all study participants?		7. Was the length of follow-up adequate?		8. Were the statistical methods well-described?		9. Were the results well-described?		Quality rating (Good, fair, or poor)
Götzinger et al[15], 2020				Yes			Yes		CD		Yes			NA	Yes		NA		Yes		Yes		Fair
Merza et al[21], 2020				Yes			Yes		CD		Yes			NA	Yes		NA		Yes		Yes		Fair
Yung et al[26], 2020				Yes			Yes		Yes		Yes			NA	Yes		NA		Yes		Yes		Fair
Study design: Cross-sectional study
Ref.	1. Was the research question or objective in this paper clearly stated?	2. Was the study population clearly specified and defined?	3. Was the participation rate of eligible persons at least 50%?		4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants?	5. Was a sample size justification, power description, or variance and effect estimates provided?		6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured?	7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed?	8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)?		9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?	10. Was the exposure(s) assessed more than once over time?			11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?	12. Were the outcome assessors blinded to the exposure status of participants?	13. Was loss to follow-up after baseline 20% or less?		14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)?		Quality rating (Good, fair, or poor)
Kim et al[16], 2020	Yes	Yes	NA		Yes	No		No	No	NA		Yes	NA			CD	NA	NA		No		Fair
Torres et al[24], 2020	Yes	Yes	NA		Yes	Yes		No	No	NA		Yes	NA			CD	NA	NA		No		Fair

CD: Can’t determine; NA: Not applicable.