| Ovid MEDLINE | 2272 |
| Ovid Embase | 2984 |
| Ovid EBM Reviews for Cochrane CENTRAL | 1409 |
| Web of Science Core Collection | 2699 |
| medRxiv | 186 |
| ProQuest Dissertations and Theses Global | 82 |
| Total number of records | 9632 |
| Total number of records after removing duplicates in Covidence | 6519 |
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