The mediational role of trust in the healthcare system in the association between generalized trust and willingness to get COVID-19 vaccination in Iran

Figures & data

Table 1. The demographic characteristics of the respondents included in this study (n = 10843)

	Mean ± SD or N(%)
Age (years)	35.54 ± 12.00
Sex
Male	4092 (37.7%)
Educational status
University	4230 (39.0%)
Diploma	2761 (25.5%)
High school	974 (9.0%)
Secondary school	1540 (14.2%)
Primary school	986 (9.1%)
No formal education	352 (3.2%)
Marital status
Married	8092 (74.6%)
Single	2751 (25.4%)
Accommodation
City	8186 (75.5%)
Rural	2656 (24.5%)
COVID-19 vaccination in the near future
Yes	8532 (78.7%)
No	2052 (18.9%)
Missing	259 (2.4%)

Response rate was 78%.

Table 2. Generalized trust and trust in health system with descriptive statistics, reliability coefficients, factor loadings, and average variance extracted statistics

Construct	Measurement item	Mean	SD	λ	α	ω	CR	AVE
Generalized Trust Scale	Most people are basically honest	2.82	1.26	0.759	0.770	0.783	0.87	0.56
	Most people are trustworthy	2.74	1.24	0.870
	Most people are basically good and kind	3.18	1.21	0.967
	Most people are trustful of others	3.03	1.19	0.830
	I am trustful	3.96	1.10	0.306
	Most people will respond in kind when they are trusted by others	3.63	1.12	0.553
Trust in Healthcare System	The Healthcare System makes too many mistakes	3.68	1.08	0.491	0.714	0.724	0.71	0.46
	The Healthcare System does its best to make patients’ health better	4.03	0.94	0.754
	The Healthcare System lies to make money	4.16	0.92	0.758

λ = Standardized factor loading from structural equation model; α = Cronbach’s alpha reliability coefficient; ω = McDonald's omega reliability coefficient; CR = Composite reliability; AVE = Average variance extracted from structural equation model.

Table 3. Demographic differences on COVID-19 vaccination willingness

	COVID-19 vaccination willingness
	No (n = 2052)	Yes (n = 8532)
	Mean (SD) or n (%)	Mean (SD) or n (%)	p-value^a
Age (years)	33.87 (11.68)	35.89 (12.04)	<.001
Sex
Male	658 (32.2%)	3242 (38.2%)	<.001
Female	1386 (67.8%)	5237 (61.8%)
Educational status
University	760 (37.3%)	3375 (39.8%)	<.001
Diploma	536 (26.3%)	2157 (25.5%)
High school	223 (11.0%)	742 (8.8%)
Secondary school	308 (15.1%)	1117 (13.2%)
Primary school	154 (7.6%)	802 (9.5%)
No formal education	55 (2.7%)	282 (3.3%)
Marital status
Married	1434 (70.4%)	6386 (75.4%)	<.001
Single	603 (29.6%)	2087 (24.6%)
Accommodation
City	1566 (76.6%)	6357 (75.0%)	.267
Rural	479 (23.4%)	2117 (25.0%)
Generalized Trust^b	3.13 (0.81)	3.25 (0.81)	<.001
Trust in healthcare system^c	3.75 (0.80)	4.00 (0.76)	<.001

^aCategorical and continuous variables were compared by calculating cluster weighted Chi-squares and the adjusted t-value.

^bGeneralized Trust was measured using a scale which had all its items summed up to get an overall score (See the method section for details). ^cTrust in healthcare system was measured using a scale which had all its items summed up to get an overall score (See the method section for details).

Table 4. Binary logistic regression of willingness to get a COVID-19 vaccine

	Willingness to get a COVID-19 vaccine
Variable	OR	95% CI	95% CI
Trust in healthcare system	1.434	1.348	1.348
Generalized trust	1.097	1.032	1.032
Constant	0.414	-	-

OR: Odds Ratio; 95% CI: 95% Confidence Interval.

Table 5. Binary logistic regression of willingness to get a COVID-19 vaccine

Outcome	OR	95% CI		p-value
Intercept	-	-	-	<.001
Age (years)	1.011	1.005	1.016	<.001
Sex (Ref. Female)	1.258	1.131	1.399	<.001
Accommodation (Ref. Rural)	0.848	0.750	0.958	.008
Married (Ref. Single)	1.154	1.019	1.306	.024
Education
University (Ref.)	-	-	-	-
Diploma	0.880	0.775	0.998	.047
High school	0.839	0.702	1.002	.053
Secondary school	0.827	0.708	0.967	.017
Primary school	1.073	0.878	1.311	.490
No formal education	0.843	0.610	1.164	.299

OR: Odds Ratio; 95% CI: 95% Confidence Interval; df = 1.

Figure 1. Mediation model via structural equation modeling showing the associations between generalized trust, trust in healthcare system, and willingness to get COVID-19 vaccination.

χ² (df) = 521.070 (65), p-value<0.001. Comparative fit index = 0.986. Tucker-Lewis index = 0.978. Root mean square error of approximation = 0.025 (0.023–0.024). Standardized root-mean-square residual = 0.0189, *p < .05, ***p= < .001. SEM was adjusted for age, sex, marital status, education, and living residence.