Table 1.
Basic characteristics of included articles.
| Study characteristics | Studies, n | ||||||
| Study type |
|
||||||
|
|
Observational study |
|
|
||||
|
|
|
Survey-based study |
|
38 | |||
|
|
|
Internet-based study |
|
42 | |||
|
|
|
Interview |
|
10 | |||
|
|
|
Mixed methods study |
|
1 | |||
|
|
Experimental study |
|
|
||||
|
|
|
Randomized trial |
|
9 | |||
|
|
|
Quasi trial |
|
2 | |||
| Risk of bias |
|
|
|||||
|
|
Low risk |
|
90 | ||||
|
|
Some concern |
|
8 | ||||
|
|
High risk |
|
4 | ||||
| Study phasea |
|
|
|||||
|
|
No report |
|
8 | ||||
|
|
Phase 1 |
|
28 | ||||
|
|
Phase 2 |
|
49 | ||||
|
|
Phase 3 |
|
1 | ||||
| Region |
|
|
|||||
|
|
Worldwideb |
|
26 | ||||
|
|
African |
|
6 | ||||
|
|
American |
|
25 | ||||
|
|
Eastern Mediterranean |
|
11 | ||||
|
|
European |
|
19 | ||||
|
|
South-East Asian |
|
5 | ||||
|
|
Western Pacific |
|
4 | ||||
|
|
More than 1 regionc |
|
6 | ||||
| Prior defined attitudes toward COVID-19 vaccinesd (n=80) |
|
|
|||||
|
|
Survey-based study |
|
|
||||
|
|
|
General population |
|
31 | |||
|
|
|
Antivaccine/vaccine hesitant population |
|
4 | |||
|
|
|
Both groups above |
|
3 | |||
|
|
Internet-based study |
|
|
||||
|
|
|
General online data |
|
22 | |||
|
|
|
Antivaccine/vaccine hesitant data |
|
19 | |||
|
|
|
Both groups above |
|
1 | |||
| Platform for internet-based studies (n=42) |
|
|
|||||
|
|
Social media |
|
|
||||
|
|
|
|
20 | ||||
|
|
|
YouTube |
|
5 | |||
|
|
|
|
4 | ||||
|
|
|
TikTok |
|
1 | |||
|
|
|
Parler |
|
1 | |||
|
|
|
Multiple social media platformse |
|
3 | |||
| Google Trends |
|
1 | |||||
| Google Images |
|
1 | |||||
| Internet news |
|
1 | |||||
| Online article database |
|
1 | |||||
| Multiple platformsf |
|
1 | |||||
aStudy phase was defined as follows: phase 1, from November 2019 to December 8, 2020; phase 2, from December 8, 2020, to November 26, 2021; phase 3 from November 26, 2021, to the latest ending date of data collection in included studies.
bStudies covering worldwide, including internet-based study with no limit in data collection (n=24), and survey-based study in multiple countries (n=2).
cStudies covering more than 1 region: 3 studies on American, European, and Western Pacific regions; and another 3 on American and European regions.
dStudy populations differ by their prior defined attitudes toward COVID-19 vaccines: studies reporting misinformation among the vaccine hesitancy or refusal group (“antivaccine/vaccine hesitant group” and “antivaccine/vaccine hesitant data” in the table), and studies which did not prior define the vaccine hesitancy or refusal group (“general population” and “general online data” in the table).
eMultiple social media platforms in 3 studies [28,72,73] were Facebook, Instagram, and Twitter; Instagram and Facebook; and YouTube, Twitter, Facebook, and Instagram.
fMultiple platforms included Google, Google Fact Check, Facebook, YouTube, Twitter, fact-checking agency websites, and websites of television and newspaper.