Table 3.

Factors influencing the decision to immunise drawing on the Health Belief Model, subjective perception risk and risky decision-making theories

	Explanatory theories	Component of theory
Factors prompting immunisation
Unfamiliarity of disease	Health Belief Model	perceived severity
	Subjective perception of risk	dread/unfamiliarity
Safe and effective vaccines	Health Belief model	perceived benefits
Healthy, robust, resilient child	counter to Health Belief Model	perceived susceptibility
Not control/contain disease	Health Belief model	perceived severity
	Subjective perception of risk	uncontrollable outcome
Trust in institution offering vaccination	Subjective perception of risk	trust mediates perception, outrage
Factors causing hesitation
Question need to prevent familiar disease	Subjective perception of risk	familiarity
Question child's resilience to side effects	Health belief model	perceived barriers
Negative impact on immune system	Health belief model	perceived barriers
Question vaccine efficacy	Health belief model	perceived benefits
Those at risk of serious illness are	Health Belief Model	perceived susceptibility
different to my child	Decision making	optimistic control
Structural barriers to completion
Continual minor illness	Health belief model	perceived barriers
Poor information	Health belief model	perceived barriers
	Decision making	ambiguity
Poor communication	Health belief model	perceived benefits
	Subjective perception of risk	outrage
	Decision making	ambiguity
Knowing schedule and organisation	Health belief model	perceived barriers
Occurrence of serious side effects	Health belief model	perceived barriers
Factors prompting non-immunisation
Dread of the unknown vaccine side effects	Subjective perception of risk	dread of unfamiliar
		uncontrollable outcome
Not safe nor effective	Health belief model	perceived benefits
Negative impact on immune system	Health belief model	perceived barriers
Safer methods to control disease	Decision making	optimistic control