Table 5.

Factors influencing COVID-19 vaccination intention.

Themes	Factors influencing COVID-19 vaccination intention
1. Sociodemographic (i) Gender	Positive effect • Male (30, 40, 41, 52, 55, 57, 60, 63, 72, 73) Negative effect • Female (62, 67, 76, 79) • Pregnant/lactating women (76) • Multiparous women (37) Direction of effect not specified • Gender (32, 35, 38, 46, 48, 58, 60, 74, 75, 77)
(ii) Age	Positive effect•Older age (36, 41–43, 47, 59, 73) • Young age groups (20–40 years old) and the older adult (over 60 years old) compared to other age groups (50) Negative effect•Younger (67) Direction of effect not specified•Age (32, 35, 38, 40, 46, 48, 58, 74, 77)
(iii) Education	Positive effect•Higher education (41, 47, 50, 57, 59, 73) • Secondary education and above (30, 36) Negative effect•Lower education (37, 62, 67, 70, 76) • Higher educational level (72) Direction of effect not specified•Education (32, 35, 38, 48, 58, 74, 75, 77)
(iv) Income	Positive effect•Higher income (43, 54, 59, 73) Negative effect • Lower income (62, 67, 76) Direction of effect not specified•Income (32, 74, 77)
(v) Occupation/profession	Positive effect•Healthcare workers (41, 59, 60, 74) • Physicians (40, 41, 52, 54) • Medical staff (50) • Healthcare workers vs. healthcare students (29) • Healthcare workers who participated in quarantine or had been in contact with confirmed cases (72) • employees (50) Negative effect•Healthcare workers (79) • Nurses vs. doctors and other healthcare workers (52, 72) • Healthcare workers vs. general population (31) Direction of effect not specified•Occupation (48, 74) • Profession (46, 77)
(vi) Ethnicity	Positive effect•White people (41, 49, 73) Negative effect • Black people (76) • Belonging to an ethnic minority group (49, 67) Direction of effect not specified•Ethnicity (74, 77)
(vii) Marital status	Positive effect•Married (59, 74)
2. Geographical	Positive effect•Continent (Asia) (44, 56) • Region (middle East) (54) • Region (South America) (31) • WHO regions of the world (51) • High-income countries (54) Negative effect • Continent (Europe) (56) • Region (Africa) (56) • Region (Middle East (31) • Rural residence (62) • High-income countries (37) Direction of effect not specified•Geographical (77) • Continent (21, 60) • Country (69, 70, 76) • Residency (74) • Regions (29, 31, 38, 60, 72)
3. Social factor	Positive effect•Social influence (Europe) (68) • COVID-19-related prosocial behaviors (44) • Social factors affecting thoughts/attitude in social contexts in general situations (32)
4. Political factor	Positive effect•Political leaning (Liberal or moderate) (74) • Political party orientation (53, 77) • Political roles (68) Negative effect • Political issues (23) • Perceived political interference (53)
5. Government role	Positive effect•Vaccine-mandates (United States) (68, 74) Negative effect•Inefficient efforts and initiatives by the government (70)
6. Study time	Positive effect•Survey year (72) • Survey month (33) Negative effect•CVI declined from 2020 to 2021 (76) • CVI declined in the second half of the study period when compared to the first half (62) • CVI declined from March 2020 to September 2020 (48) • CVI declined pre- to post-pandemic (56) • CVI declined from first survey to second survey (60)
7. Attitude	Positive effect•Attitude toward vaccine (21, 30, 32, 34, 41, 57, 58, 74, 80) • Attitudes toward vaccination (34, 43)
8. Perceived severity	Positive effect•Lower level of perceived vaccine harms (73, 76) Negative effect•Perceived severity of COVID-19 infection (76) • Concerns for adverse reactions to COVID-19 vaccine (23, 42, 45, 61) • Concerns about side effects and safety (29, 38, 45, 52, 53, 68, 75, 80)
9. Perceived susceptibility	Positive effect•perceiving risk/susceptibility of COVID-19 infection (1, 35, 41, 43, 45, 48, 52, 53, 59, 63, 73, 74) • fear about COVID-19 (41, 46, 59) • anxiety about COVID-19 (27)
10. Perceived benefits	Positive effect•Perceived benefit of COVID-19 vaccine (23, 35, 59, 74) • Perceived efficacy of the COVID-19 vaccine (29, 38, 48, 60, 68, 74, 80) • Public confidence in the vaccines' efficacy (29, 48, 64, 68) Negative effect • Concerns about efficacy and effectiveness of COVID-19 vaccine (52)
11. Perceived barriers	Negative effect•Financial barriers (34, 74) • Shortage of vaccine (79) • Logistical issues (49)
12. Self-efficacy and perceived behavioral control	Positive effect•Confidence in their ability to receive COVID vaccine (21, 41, 42, 74) • Perceived behavioral control (21) Negative effect•Low confidence in the health system (1)
13. Norms	Positive effect•Subjective norms (21) • Social norms (74)
14. Trust	Positive effect•Trust in vaccine (50, 68) • Trust in the vaccine effectiveness (28) • Trust in public health agencies/health science (47) • Trust in healthcare system (59, 74) • Trust in medical system (64) • Trust in government and public health authorities (44, 48, 64, 75, 80) • Trust in the accuracy of the measures taken by the government (46) • Trust in information sources (38, 44) Negative effect • Mistrust in healthcare system (38) • Distrust of the government and healthcare system (23, 53) Lack of social trust (29)
15. Conspiracy theory, propaganda, and misinformation	Negative effect•Anti-vaccine conspiracy theories and beliefs (61, 66, 68) • Propaganda (59) • Misinformation or negative information (1, 23, 49)
16. Knowledge	Positive effect•Knowledge about COVID-19 vaccine (30, 35, 57, 59, 64, 80) • Knowledge about COVID-19 (32, 44)
17. Information and Communication	Positive effect•Information sufficiency (68) • Inclusive communications which address vaccine concerns via trusted communicators (49) • Increased visibility of minority ethnic groups in the media (49)
	•Explicit communication about the safety of COVID-19 vaccines for pregnant women (47) • Trusted information sources (44) • Access to scientific information from public health authorities and physicians (39) Negative effect • Lack of information about the vaccine's safety (29, 49) • Inaccessible communications (49)
18. Recommendation for vaccination	Positive effect•recommended for vaccination by others (34, 39, 53, 74) • recommended for vaccination to others (46)
19. Vaccination history	Positive effect•Influenza vaccination history (39–43, 48, 52, 55, 59, 65, 71, 75) • Inoculation history (50, 53, 77) • Up-to-date on vaccinations (74) • Receiving any vaccine in the past 5 years (74)
20. History of COVID-19 infection	Positive effect•COVID-19 self-history (29, 30, 59, 74, 77) • COVID-19 family history (77) Negative effect • Previous COVID-19 infection (28)
21. Health status and well-being	Positive effect•Having chronic diseases (28, 36, 59, 74) • Comorbidities (41, 45, 46, 77) • Early cancer stages (stages I and II) (65) • Depression symptoms in the past week (46) • Mental well-being (77)
22. Other factors	Positive effect•Contact with suspected or confirmed COVID-19 patients (41) • Health insurance (74) • Religious beliefs (38) • Cues to action (74)