Table 2.
Identified studies on vaccination willingness
| Authors, publication date | Data collection | Sample | Surveyed variable | Measures | Main findings |
|---|---|---|---|---|---|
| Bertin et al. [34] | 17.4–25.4 2020 | N = 396, Mage (SD) = 26.1 (10.3), non-representative French sample | Vaccination willingness | Conspiracy belief: Scales from 1 (strongly disagree) to 5 (strongly agree), 7 items on Outgroup-conspiracies, 3 items on Ingroup-conspiracies; Vaccination willingness: 1 item, scale from 1 (I would definitely not be vaccinated under any circumstances) to 7 (I would be vaccinated without hesitation) | Conspiracy belief sig. negatively correlated with vaccination willingness: Outgroup: r = − 0.23, p < 0.001; Ingroup: r = − 0.28, p < 0.001; Conspiracy belief is a sig. negative predictor for vaccination willingness: Outgroup: β = − 0.23, 95% CI [− 0.34, − 0.12], p < 0.001; Ingroup: β = − 0.11, 95% CI [− 0.22, − 0.01], p = 0.05 |
| Earnshaw et al. [28] | 13.4–14.4 2020 | N = 845, Mage (SD) = 40.15 (11.67), non-representative US American sample | Vaccination willingness | Conspiracy belief: 6-item questionnaire on different conspiracy narratives (agree/disagree); Vaccination willingness: 1 item on a 5-level Likert-scale | 72.9% of the participants believing in conspiracies were willing to get vaccinated vs. 92.0% of those who don’t believe in conspiracies, X2 (1) = 55.72, p ≤ 0.01; Sig. negative association of vaccination willingness and conspiracy belief: b (SD) = − 1.37 (0.28), OR = 0.26, 95% CI [0.15–0.44], p ≤ 0.01 |
| Freeman et al. [35] | 24.9–17.10 2020 | N = 5114, Mage (SD) = 46.9 (17.1), representative sample from the UK regarding age, gender, ethnicity, income and region | Vaccination hesitancy | OCEANS coronavirus conspiracy scale: 14 items on conspiracy belief, scale from 1 (do not agree) to 5 (agree completely); Oxford COVID-19 hesitancy scale: 7 items on vaccination hesitancy, scale from 1 to 5 (higher score equals higher vaccination hesitancy) | Conspiracy belief correlated with vaccination hesitancy: r = 0.38, p < 0.001; Conspiracy belief sig. predicted vaccination hesitancy: b (SD) = 1.63 (0.05), p < 0.001; SEM model: β = 0.39, p < 0.001 |
| Freeman et al. [23] | 4.5–11.5 2020 | N = 2501, Mage (SD) = 46.6 (17.3), English sample, quota sampled to match the population for age, gender, income, and region | Willingness to take diagnostic or antibody tests or to be vaccinated | Conspiracy belief: 48 items, scale from 1 (do not agree) to 5 (agree completely); Future medical tests and treatment: inc. 1 item on vaccination willingness: 6 items, scale from 1 (definitely) to 5 (definitely not) | Sig. negative correlation of specific and general conspiracy belief and vaccination willingness: r = 0.35 and r = 0.37, p < 0.001; Participants that believed COVID-19 is a bioweapon (OR = 2.11, 95% CI [1.65, 2.70]) or Jews created the virus for financial gain (OR = 2.70, 95% CI [2.08, 3.50]) reported less vaccination willingness then people not holding conspiracy beliefs |
| Garry et al. [31] | 16.7–19.7 2020 | N = 1045, representative sample of the English population | Vaccination willingness | 6 items on different conspiracy narratives on a 7-level scale (strongly disagree, disagree, slightly disagree, slightly agree, agree, strongly agree, don’t know); 1 item on vaccination willingness on a 5-level scale (yes definitely, yes probably, no probably not, no definitely not, don’t know) | Conspiracy belief sig. negatively predicted vaccination unwillingness: b (SD) = 0.45 (0.05), β = 0.35, p < 0.001 |
| Prati [36] | April 2020 | N = 624, Mage (SD) = 32.31 (12.69), non-representative Italian sample | Vaccination willingness | Conspiracy belief: 1 item (yes/no/don’t know); 1 item on vaccination willingness (yes/no/don’t know) | Conspiracy belief was no sig. predictor for vaccination unwillingness: OR = 0.88, 95% CI [0.22, 3.55] |
| Romer and Jamieson [29] | 17.3–27.3 2020; 10.7–21.7 2020 | N = 840, representative US American sample in terms of age, gender, race/ethnicity and education | Vaccination willingness | Conspiracy belief: 3-item questionnaire (3 different conspiracy narratives), scale from 1 (definitely false) to 4 (definitely true) 1 item on vaccination willingness scale from 1 (not at all likely) to 4 (very likely) | Conspiracy belief in March negatively predicted vaccination willingness in July: β = − 0.29, 99% CI [− 0.37, − 0.22], p ± 0.005 |
| Salali and Uysal [37] | May 2020 | UK: N = 1088, Mage (SD) = 31.92 (11.2), Turkey: N = 3936, Mage (SD) = 44.33 (13.70), non-representative samples | Vaccination willingness | Conspiracy belief: 1 item (natural/artificial/not sure); 1 item on vaccination willingness (yes/no/not sure) | Conspiracy belief about the artificial origin of the virus was associated with sig. less vaccination willingness, UK: artificial origin OR = 0.78, 95% CI [0.49, 1.25], p = 0.31; natural origin, OR = 2.63, 95% CI [1.83, 3.78], p < 0.001; Turkey: artificial origin OR = 0.65, 95% CI [0.53, 0.79], p < 0.001; natural origin, OR = 2.26, 95% CI [1.93, 2.66], p < 0.001 |
| Sallam et al. [38] | 14.12–18.12 2020 | N = 3414, non-representative Arabic sample (mostly from Jordan (63.6%) and Kuwait (22.6%), plus 16 other Arab states) | Vaccination willingness | 4 items on conspiracy narratives (yes/no, resp. natural source/man-made virus), 1 item on vaccination willingness (yes/no) | Conspiracy belief was associated with sig. less vaccination willingness (95% CI, p < 0.001): COVID-19 man-made: OR = 0.47, CI [0.38, 0.57]; COVID-19 was manufactured to force the public to get vaccinated: OR = 1.89, CI [1.46, 2.43]; COVID-19 vaccine is used to implant microchips into people to control them: OR = 2.39, CI [1.72, 3.30]; COVID-19 vaccine will lead to infertility: OR = 2.73, CI [1.90, 3.93] |
| Teovanović et al. [22] | 10.4–22.4 2020 | N = 407, Mage (SD) = 34.88 (12.81), non-representative Serbian sample | Vaccination willingness | 13 items on conspiracy narratives, scale from 1 (completely disagree) to 5 (completely agree); 1 item on vaccination willingness, scale from 1 (definitely would not) to 5 (definitely would) | Conspiracy belief correlates sig. negatively with vaccination willingness: r = − 0.53, p < 0.05; Conspiracy belief sig. negative predictor for vaccination willingness: b (SD) = − 0.92 (0.07), 95% CI [− 1.07, − 0.78], p < 0.002 |
Sig. = significant, n.sig. = not significant