| Study | Reason for exclusion |
|---|---|
| Ali 2021 | Single‐arm study with less than 100 participants (53) |
| American Society of Safety Professionals 2021 | Not an intervention study |
| Batteux 2021 | Investigates scenarios that cannot be manipulated |
| Bell 2021 | Not an intervention study |
| ChiCTR2100043018 | Not an intervention study |
| Community Practitioner 2021 | Not an intervention study |
| Crawshaw 2021 | Does not summarise interventions to increase uptake |
| Crawshaw 2021b | Does not summarise interventions to increase uptake |
| Davis 2021 | Hypothetical scenario that cannot be manipulated (vaccine efficacy) |
| Gakuba 2021 | Uncontrolled study with less than 100 participants (n = 61) |
| Gehrau 2021 | Not an intervention study |
| Guelmami 2021 | Not an intervention study |
| Hofer 2021 | Wrong publication type (opinion piece) |
| Kaplan 2021 | Investigates scenarios that cannot be manipulated |
| Kirkpatrick 2021 | Wrong vaccine (MMR) |
| Knight 2021 | Development but not testing of an intervention |
| Kumar 2021 | Not an intervention study |
| Lim 2020 | Not an intervention study |
| Loomba 2021 | Wrong publication type (correction) |
| Loomba 2021a | Measures the effect of misinformation on vaccine intent and thus not relevant to the research objective |
| NCT04694651 | Not an intervention study |
| Rahmandad 2021 | Not an intervention study |
| Salali 2021 | Not an intervention study |
| Shmueli 2021 | No intervention |
| Sprengholz 2021b | Wrong publication type |
| Thaker 2021 | Measures effect of vaccine misinformation |
| Vasquez 2021 | Not an intervention study |
| Wagner 2021 | Not an intervention study |
| Yousuf 2021 | Intervention targets influenza vaccine, not COVID‐19 vaccine |
| Yuen 2021 | Not an intervention study |
MMR: measles, mumps and rubella.