Table 2

Factors associated with past influenza vaccination in regression analysis—USA

Variables	M1		M2		M3		M4		M5		M6		M7		M8
Variables	OR	SE	OR	SE	OR	SE	OR	SE	OR	SE	OR	SE	OR	SE	OR	SE
Age	1.019	0.458	1.369	0.271	1.210	0.275	1.116	0.292	1.230	0.396	1.006	0.443	1.093	0.441	1.057	0.446
Eligible health condition	2.528**	0.329	3.050***	0.204	3.079***	0.208	2.469***	0.222	2.145**	0.296	2.549**	0.320	2.531**	0.320	2.531**	0.323
Private insurance	3.463***	0.386	2.833***	0.242	2.611***	0.246	2.197**	0.265	2.394**	0.337	3.062**	0.367	3.269***	0.372	3.374***	0.377
Public insurance	4.507***	0.415	3.461	0.258	3.143***	0.262	2.542***	0.282	3.163***	0.362	4.137***	0.391	4.158***	0.391	4.273***	0.397
Gender	0.916	0.269	0.913	0.166	0.948	0.171	0.859	0.185	0.907	0.240	0.931	0.253	0.867	0.257	0.898	0.259
Marital status	0.672	0.294	1.093	0.185	1.062	0.188	1.032	0.204	0.890	0.266	0.743	0.281	0.759	0.283	0.728	0.286
Income	1.146*	0.074	1.198***	0.046	1.166**	0.049	1.140**	0.052	1.145**	0.067	1.143*	0.070	1.130*	0.070	1.145*	0.070
Education	1.052	0.095	0.740	0.182	1.036	0.062	0.983	0.067	1.025	0.088	1.046	0.093	1.042	0.093	1.035	0.093
Ethnicity	0.664	0.287	1.369*	0.271	0.681**	0.186	0.665**	0.202	0.681	0.254	0.677	0.266	0.695	0.270	0.693	0.271
Vaccine access	1.277	0.384
Time to vaccinate	2.182**	0.356			2.804***	0.220	2.565***	0.239	2.417**	0.303	2.194**	0.319	2.535**	0.329	2.432**	0.331
Physician’s opinion	4.361***	0.345					6.909***	0.211	2.946***	0.276	3.700***	0.309	4.260***	0.322	4.285***	0.321
Relatives’ opinion	0.866	0.312
Vulnerable to influenza	1.335***	0.069							1.359***	0.056	1.291***	0.059	1.284***	0.059	1.290***	0.060
Susceptible to influenza	1.013	0.056
Likelihood of catching influenza	1.235***	0.060							1.238***	0.049	1.238***	0.055	1.226***	0.056	1.216***	0.056
Severity of influenza (bed-days)	1.121	0.126
Severity of influenza	0.908*	0.061							0.911*	0.051	0.902*	0.055	0.909*	0.055	0.903**	0.055
Fear of influenza	0.973	0.063
Worry of transmitting influenza	0.932	0.056
Perceived control over influenza	0.752***	0.056							0.741***	0.047	0.757***	0.052	0.748***	0.052	0.744***	0.052
Regret of catching influenza	1.165**	0.054							1.112**	0.043	1.117**	0.049	1.126**	0.049	1.122**	0.050
Perceived knowledge of vaccine	0.406**	0.390									0.368**	0.361	0.368**	0.366	0.388**	0.367
Effectiveness of vaccine	1.249***	0.066									1.188**	0.062	1.222**	0.064	1.225***	0.064
Vaccine transmits influenza	0.848**	0.054									0.827***	0.046	0.835***	0.046	0.836***	0.047
Vaccine contents are dangerous	0.961	0.055
Vaccine is painful	1.775*	0.329									1.712*	0.304	1.585	0.309	1.558	0.310
Vaccine-related self-efficacy	1.010	0.053
Trust in physician (scale)	0.836*	0.096											0.796**	0.090	0.809**	0.091
Trust in manufacturers	0.895	0.081
Trust in health authorities	1.013	0.086
Shared decision-making doctor	0.953	0.147
Bad experience vaccines—child	1.449	0.417
Scary health experience—child	2.126*	0.464													2.153*	0.450
Number of participants	724		724		724		724		724		724		724		724
Nagelkerke R	0.734		0.215		0.252		0.389		0.686		0.719		0.725		0.727

The change in model fit indicated by χ² test for each block of variables was always significant (p<0.1). *p<0.1; **p<0.05; ***p<0.001. In bold are the variables significantly associated with vaccination uptake in the final model (M8).