Maternal influenza vaccination relates to receiving relevant information among pregnant women in Japan

Figures & data

Table 1. Characteristics of respondents in the survey conducted in 2017 and 2018, in Japan.

	Survey in year 2017		Survey in year 2018
	Number	%	Number	%	p value^e
Total number of respondents	2204	-	3580	-
Age
Mean (years)	32.5	-	32.3	-	0.141
20–29	577	27.8	994	26.2
30–39	1488	65.7	2352	67.5
40–49	139	6.5	234	6.3
Homemaker^a (yes)	1043	47.3	1607	44.9	0.071
Pregnancy (yes)	828	37.6	2,385	66.6	0.000
Other child/children (yes)	1135	51.5	1974	55.1	0.007
Educational background
Education period (years)	14.1		14.1		0.429
Junior high school	71	3.2	123	3.4
High school	566	25.7	872	24.4
Vocational college	400	18.1	692	19.3
Junior collage	328	14.9	516	14.4
University	779	35.3	1,267	35.4
Graduate school	60	2.7	73	2.0
Other	0	0.0	2	0.1
No answer	0	0.0	35	1.0
Awareness of influenza vaccination in pregnancy (yes)	1920	87.1	3084	86.1	0.295
Received recommendation (yes)^b	1293	58.7	2000	55.9	0.024
Influenza vaccination
Annual	854	38.7	1,251	34.9	0.000
Ever or sometimes	907	41.2	1,577	44.1
Never	443	20.1	752	21.0
Vaccination during pregnancy (yes)	1180	53.5	1697	47.4	0.000
Could not be vaccinated because of vaccine shortage^c	-	-	173	4.8
Household income
< 2 M JPY^d (18 K USD)	81	3.7	152	4.2
2 to 4 M JPY (18 to 36 K USD)	423	19.2	797	22.3
4 to 6 M JPY (36 to 55 K USD)	518	23.5	889	24.8
6 to 8 M JPY (55 to 73 K USD)	304	13.8	472	13.2
8 to 10 M JPY (73 to 91 K USD)	168	7.6	238	6.6
10 to 20 M JPY (91 to 182 K USD)	88	4.0	129	3.6
over 20 M JPY (182 K USD)	8	0.4	5	0.1
Do not know	340	15.4	521	14.6
Do not want to answer	274	12.4	377	10.5

^aOther includes maternity leave and working.

^bTable 2 shows further detail.

^cThe option “could not be vaccinated because of the vaccine shortage” was only included in the 2018 survey.

^d1 USD = 110 JPY.

^et-test for age and education period, Chi-square test for homemaker, pregnancy, other child/children, awareness of influenza vaccination for pregnancy, personal communication regarding vaccine uptake, and personal communication regarding vaccine uptake. One-way analysis of variance for influenza vaccination.

Abbreviations: M, million; K, thousand.

Table 2. The key sources who might influence a pregnant woman’s decisions about vaccination in the survey conducted in 2017 and 2018, in Japan.

	2017				2018
	Vaccinated	%	Unvaccinated	%	Vaccinated	%	Unvaccinated	%
Obstetrician	793	77.9	115	63.5	1164	79.9	303	66.7
General practitioner	60	5.9	13	7.2	103	7.1	25	5.5
Pediatrician	41	4.0	9	5.0	48	3.3	16	3.5
Nurse or midwife	154	15.1	27	14.9	204	14.0	79	17.4
Friend	103	10.1	24	13.3	170	11.7	74	16.3
Family member	201	19.7	35	19.3	269	18.5	65	14.3
Colleague	27	2.7	5	2.8	37	2.5	6	1.3
Other	0	0	0	0	3	0.2	5	1.1
Total	1379		228		1998		573

The total number of respondents who received personal communication was 1293 in 2017 and 2000 in 2018. The sum was not 100% because multiple answers were allowed. The total number of vaccinated and unvaccinated respondents who received advice was 1018 in 2017 and 1456 in 2018 (vaccinated), 181 in 2017 and 454 in 2018 (non-vaccinated).

Figure 1. Sources who gave recommendation regarding vaccination among vaccinated respondents in 2017.

Figure 2. Sources who gave recommendation regarding vaccination among vaccinated respondents in 2018.

Figure 3. Sources who gave recommendation regarding vaccination among non-vaccinated respondents in 2017.

Figure 4. Persons who gave recommendation regarding vaccination among non-vaccinated respondents in 2018.

Table 3. Logistic regression model in the survey conducted in 2017 and 2018, in Japan.

	Pooled						2017						2018
	Bivariate OR (95%CI)			Multivariate OR (95%CI)			Bivariate OR (95%CI)			Multivariate OR (95%CI)			Bivariate OR (95%CI)			Multivariate OR (95%CI)
Age	1.040	1.028	1.052	1.004	0.983	1.024	1.045	1.025	1.064	1.000	0.965	1.036	1.037	1.022	1.052	1.003	0.979	1.029
Homemaker (yes)	0.754	0.680	0.837	0.956	0.797	1.146	0.744	0.629	0.880	0.853	0.623	1.168	0.752	0.659	0.859	1.027	0.820	1.286
Pregnancy at the survey point (yes)	0.766	0.690	0.850	0.751	0.623	0.905	1.203	1.011	1.431	1.229	0.898	1.680	0.620	0.539	0.714	0.544	0.429	0.690
Having other child/children	0.939	0.847	1.042	0.593	0.493	0.712	1.094	0.925	1.294	0.700	0.512	0.958	0.866	0.759	0.988	0.535	0.426	0.673
Education background
Education period (years)	1.305	1.255	1.358	1.069	1.018	1.123	1.202	1.148	1.257	0.999	0.919	1.086	1.226	1.181	1.272	1.120	1.052	1.191
Having annual influenza vaccination
Never or Ever		-					-						-
Annual	19.405	16.690	22.560	16.903	13.569	21.055	33.774	25.281	45.121	29.948	19.840	45.207	14.865	12.425	17.784	13.062	10.021	17.027
Awareness of influenza vaccination in pregnancy (yes)	148.515	70.417	313.228	34.864	13.879	87.582	148.378	47.392	464.552	22.481	6.409	78.857	149.703	55.821	401.481	52.005	12.587	214.864
Received recommendation (yes)	15.651	13.706	17.872	10.430	8.575	12.686	17.115	13.793	21.238	11.105	7.884	15.642	14.871	12.560	17.606	10.395	8.153	13.254
Income*	1.097	1.074	1.121	1.007	0.974	1.042	1.081	1.044	1.118	0.988	0.934	1.045	1.105	1.074	1.137	1.024	0.982	1.069
Dummy year (2018 = 1)	0.782	0.703	0.870	0.845	0.698	1.023	-						-

*Income was included as a continuous variable. Missing data such as “Do not know” and “Do not want to answer” in income question were omitted (N = 4257 [pooled], 1590 [2017], 2667 [2018]) in the multivariate model.

Respondents who chose “could not be vaccinated because of the vaccine shortage” in survey year 2018 were classified as non-vaccinated.

Abbreviations: OR, odds ratio; CI, confidence interval