Table 2.

Effect direction plot.^a,b

Study	Study design	Days unvaccinatedc	Uptake of vaccinesd	Vaccine acceptanced
Daley et al [63]	Randomized controlled trial	N/Ae	N/A	▲f
Glanz et al [64]	Randomized controlled trial	▲	N/A	N/A
O’Leary et al [65]	Randomized controlled trial	N/A	▲	N/A
Liao et al [69]	Randomized controlled trial	N/A	◄►g	N/A
Zhang et al [70]	Online survey experiment	N/A	N/A	▲
Ugarte et al [68]	Randomized controlled trial	N/A	N/A	▲
Abdel-Qader et al [71]	Randomized controlled trial	N/A	▲	N/A
Brandt et al [72]	Controlled quasi-experimental mixed methods	N/A	N/A	▲
Lau et al [67]	Randomized controlled trial	N/A	▲	N/A

^aStudy design: assessed as a randomized controlled trial.

^bItalicized entries indicate a low risk of bias; nonitalicized entries indicate some concerns.

^cNumber of trials or experiments must be ≥2, and so, it was not possible to calculate the P value for the outcome “Days unvaccinated.”

^dSign test for positive effect direction (1-tailed): P=.13 for both uptake of vaccines and vaccine acceptance.

^eN/A: not applicable.

^fPositive health impact.

^gNo change/mixed effects/conflicting findings.