Table 2. Risk of bias in the included studies.
| Study ID | Disease | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | Score† |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Li 2020 (26) | COVID-19 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 5 |
| Zhang 2004 (27) | SARS | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 |
| Zhang 2003 (28) | SARS | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 |
| Lu 2003 (29) | SARS | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 |
| Liang 2004 (30) | SARS | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 |
| Li 2005 (31) | SARS | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 |
| Li 2005 (32) | SARS | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 |
| Kaydos-Daniels 2004 (33) | SARS | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 5 |
| Ma 2005 (34) | SARS | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 1 | 7 |
†, according to the methodology evaluation tool recommended by the Agency for Healthcare Research and Quality. The maximum score is 1; the higher the score, the lower the risk of bias. The numbers 1 to 11 refer to the items of the tool: 1. Defining the source of information (survey, record review); 2. Listing the inclusion and exclusion criteria for exposed and unexposed subjects or referring to previous publications; 3. Indicate time period used for identifying patients; 4. Indicating whether the subjects were recruited consecutively (if not population-based); 5. Indicating if evaluators of subjective components of the study were masked from the participants; 6. Description of any assessments undertaken for quality assurance purposes (e.g., test/retest of primary outcome measurements); 7. Explaining any exclusions of patients from the analysis; 8. Description how confounding was assessed and/or controlled; 9. If applicable, explaining how missing data were handled in the analysis; 10. Summarizing patient response rates and completeness of data collection; 11. Clarification of the expected follow-up (if any), and the percentage of patients with incomplete data or follow-up.