Table 1.

Sample Characteristics of Completed Participants in Intent to Treat Analysis

	Control (n = 268)		Intervention (n = 260)
	Mean	SD	Mean	SD
Age	35.17	10.90	35.51	12.50
Vaccine History (0–5)	2.47	1.70	2.47	1.68
Vaccine Sensitivity (1–6)	1.88	0.90	1.94	0.85
Antivax Attitudes (1–6)	2.28	0.80	2.40	0.85
Gender
Male	n = 138		n = 129
Female	n = 125		n = 127
Gender diverse	n = 4		n = 4
Ethnicity
NZ European	n = 144		n = 140
Other	n = 124		n = 120

Note: Vaccine History is the number of flu shots in the past 5 years (0–5). Vaccine Sensitivity measured with four items of the Brief Perceived Sensitivity to Medication Scale with “medicines” replaced by “vaccinations” [14] (1 = strongly disagree to 6 = strongly agree). Anti-Vaccine Attitudes measured with four items of the Vaccination Attitudes Examination Scale [15] (1 = strongly disagree to 6 = strongly agree). Dropout rates did not significantly differ by condition (15% in the treatment condition and 17% in the control condition) (F = 0.076, p < .783, η² = 0.000) and there were no differences between participants in the control and mindset intervention conditions with respect to age, gender, vaccine history, or antivax attitudes (all ps > .11) suggesting that missingness was not selective to randomized condition [16].