Psychological determinants of COVID-19 vaccine acceptance: A comparison between immigrants and the host population in Japan

Abstract

This study explored the differences in COVID-19 vaccination readiness based on the 7C model and its association with vaccine acceptance among foreign-born immigrants, Japan-born immigrants, and locals in Japan. A cross-sectional survey was conducted in October 2021 (n = 3,690). Our results show that COVID-19 vaccination readiness, acceptance, and their relationship differ according to migratory status and nativity. Immigrant participants reported higher general vaccination readiness and acceptability for vaccination against COVID-19 than the Japanese participants, but had lower vaccination coverage, particularly among those born in Japan. The psychological determinants of Japan-born immigrants were more similar to those of Japanese participants than those of foreign-born immigrants. The effects of confidence, complacency, and constraints on COVID-19 vaccine acceptance were strong among all three groups. However, the role of collective responsibility and conspiracy varied by migratory status. This study highlighted the importance of culturally tailored interventions in vaccine delivery to immigrants.

1. Introduction

Increasing evidence indicates a disparity in COVID-19 vaccination coverage and acceptance between immigrants or ethnic/racial minorities and the host population [1], [2], despite the observed disproportionate impacts (e.g., higher rates of COVID-19 infection and mortality) among minority groups during the pandemic [3], [4], [5]. Thus, the importance of culturally tailored health interventions for immigrants is emphasized. To design customized vaccination promotions, it is crucial to understand the differences in factors related to COVID-19 vaccine intentions between immigrant and host populations. The contribution of migration and socioeconomic status to disparities in vaccination acceptance has been extensively assessed [6] unlike the differences in psychological factors, such as vaccination readiness and its association with COVID-19 vaccine acceptance, between immigrant and host populations.

Vaccination readiness is defined as the willingness to be vaccinated and the components that increase or decrease an individual's likelihood of getting vaccinated [7]. According to the 7C model, an extension of the 5C model, vaccination readiness comprises confidence (trust in the safety and effectiveness of vaccines and health authorities), complacency (seeing a high need for vaccination due to a high perceived risk of the disease), constraints (not seeing any hurdles in everyday life that hinder vaccination), calculation (comparing personal costs against benefits of receiving a vaccination versus a non-vaccination), collective responsibility (willingness to protect others through one’s own vaccination), compliance (support for social monitoring and sanctioning of people who are not vaccinated), and conspiracy (a low belief in vaccination-related conspiracy theories) [7], [8], [9]. Previous studies have shown that these components can explain differences in COVID-19 vaccination intentions [7], [8], [10], [11].

Based on the 7C Scale and a nationwide survey in Japan, this study aimed to explore differences in COVID-19 vaccination readiness and its relationship with COVID-19 vaccine acceptance between immigrants and the host population. Additionally, considering that vaccination intention and its determinants may vary by nativity [12], we divided immigrants into Japan-born and foreign-born groups. Unlike many other countries, such as the U.S., birthright citizenship is not permitted in Japan. If both parents are foreign nationals, their child born in Japan is also considered a foreign citizen. Thus, all native-born descendants of immigrants need to undergo the formal naturalization process to become full citizens. Owing to the social system (e.g., education of foreign children is not compulsory in Japan) and parental resource constraints (e.g., language, financial resources, and social networks), many second-generation immigrants in Japan demonstrate low educational attainment and, thus, poor integration [13]. As education and integration levels are important determinants of vaccine acceptance [14], the disadvantages of the socioeconomic integration of Japan-born immigrants may affect their uptake of the COVID-19 vaccine.

2. Method

2.1. Data collection

We conducted a nationwide Internet survey among foreign national residents of Japan aged 20 years or above (from October 5–14, 2021) and Japanese national residents (from October 26–28, 2021). The COVID-19 vaccination in Japan began in February 2021 and is free for all residents of Japan, including immigrants [14]. During the survey period, infections in Japan were very low; the proportion of the fully vaccinated population was 60.2% on October 5, 2021 [15].

Immigrants are typically hard-to-survey populations [16], and a complete sampling frame is unavailable in Japan. Therefore, we attempted to reach maximum immigrants by conducting the survey using the largest online survey panelist network in Japan through a survey agency called GMO Research. All registered foreign-nation monitors were invited to participate in the survey (n = 20,222). Thereafter, the data of their Japanese counterparts were also collected through the same survey agency. Japanese participants were selected via quota sampling based on sex, age, and region of residence to ensure that the basic characteristics of the Japanese sample were similar to those of the immigrant sample, as the distribution of age and geography among immigrants is significantly different from that of locals in Japan. We obtained 1986 and 1704 valid responses from the immigrant and Japanese participants, respectively. The questionnaire for the immigrant survey was available in Japanese (n = 1728, 87%), English (n = 156, 7.9%), and plain Japanese (Yasashii Nihongo), a writing style using easy phrases and fewer Chinese characters (n = 102, 5.1%). Additionally, the foreign-born and Japan-born immigrant participants were 1485 and 501, respectively. In addition, the number of refugees in Japan is very small (fewer than 100 refugee claims are approved each year) compared to those in other countries; hence, it is unlikely that the immigrant participants in this study included refugees.

The ethics review board of the Center for Northeast Asian Studies of Tohoku University granted ethical approval for this study (CNEAS-ER2021-04). Informed consent was obtained from all the participants.

2.2. Measures

2.2.1. Migration status

In this study, immigrants and the host population were distinguished by nationality. Immigrants refer to those who reside in Japan but do not have Japanese citizenship, whereas host population refers to residents who have Japanese citizenship. Since the 1990s, the Japanese government has adopted various measures to attract migrant workers to address the growing labor shortage due to declining birth rates and an aging population. The foreign population of Japan was 2.8 million at the end of 2021, comprising 2.2% of the overall population (see Supplementary Table 1 for further information). In addition to these recent immigrants, a large portion of Japan’s foreign population is made up of Korean migrants, who arrived in Japan during the colonial era (1910–1945), and their descendants, many of whom experienced discrimination and marginalization. For many Koreans and their descendants, the act of renouncing their Korean nationality is equivalent to giving up their Korean identity; therefore, they choose to maintain their Korean nationality [17].

2.2.2. Vaccine intentions

We asked all participants about their COVID-19 vaccination experience and those who were not fully vaccinated about their intentions to receive the vaccine. The question was, “Do you plan to get vaccinated?” with response options: “Yes, I have already made an appointment,” “Yes, but I haven't made the appointment,” “No, I don't want to be vaccinated,” and “I haven't decided yet.” We defined the acceptance group as those who were fully vaccinated and those who were not fully vaccinated but planned to get vaccinated. The remaining participants who stated that they did not want to be vaccinated or had not decided yet were the hesitant group.

2.2.3. Vaccination readiness

To measure the readiness for the COVID-19 vaccine, we adapted the short version of the 7C Scale. Participants reported the degree, ranging from “strongly disagree” = 1 to “strongly agree” = 7, to seven statements referring to the COVID-19 vaccine: a. “I am convinced the appropriate authorities do only allow effective and safe vaccines (Confidence);” b. “I get vaccinated because it is too risky to get infected (Complacency);” c. “Vaccinations are so important to me that I prioritize getting vaccinated over other things (Constraints);” d. “I only get vaccinated when the benefits outweigh the risks (Calculation);” e. “I see vaccination as a collective task against the spread of diseases (Collective responsibility);” f. “It should be possible to sanction people who do not follow the vaccination recommendations by health authorities (Compliance);” g. “Vaccinations cause diseases and allergies that are more serious than the diseases they ought to protect from (Conspiracy).” The scores for “Calculation” and “Conspiracy” were reverse-coded. Additionally, the mean score of the seven items was calculated to represent general vaccination readiness. Higher scores indicated higher vaccination readiness.

2.3. Statistical analysis

We first calculated descriptive statistics for all variables among the total samples and by migratory status (i.e., foreign-born immigrants, Japan-born immigrants, and Japanese). We then performed stratified analyses based on the migratory status. A Poisson regression with robust standard errors was used to investigate the association between COVID-19 vaccination readiness and acceptability. Vaccine intention was the dependent variable, whereas the components of vaccine readiness were the independent variables. The rate ratios controlled for sex, age, education, marital status, working status, home country or region (only for immigrant groups), and COVID-19 infection history were estimated. Additionally, a seemingly unrelated regression test (SUEST) was used to test for differences in the estimated rate ratios between groups. Statistical analyses were performed using Stata/SE 17.0.

3. Results

Table 1 shows the sociodemographic characteristics, COVID-19 vaccine uptake, and intentions of the participants according to their migratory status. Approximately 61% of the participants were female. The average ages of foreign-born, Japan-born immigrant, and Japanese participants were 37.2, 41.8, and 40.1 years, respectively. The proportion of those who received two doses of the COVID-19 vaccine was highest among the Japanese (70.6%) and lowest among Japan-born immigrants (57.29%). Although the proportion of foreign-born immigrants who were fully vaccinated (66.26%) was lower than that of Japanese participants, they were less hesitant about vaccination (11.58%) than the Japanese (15.32%) and Japan-born immigrants (17.96%).

Table 1.

Descriptive statistics of the participants.

	All (n = 3,690)	Foreign-born Immigrants (n = 1,485; 40.2%)	Japan-born Immigrants (n = 501; 13.6%)	Japanese (n = 1,704; 46.2%)
Vaccine uptake and intentions (%)
Acceptant (vaccinated or intent)	85.83	88.42	82.04	84.68
Fully vaccinated	67.05	66.26	57.29	70.60
Hesitant (refusal or unsure)	14.17	11.58	17.96	15.32
Refusal	9.62	6.80	10.58	11.80
Vaccine readiness (mean)	4.25	4.43	4.11	4.13
Confidence (mean)	4.42	4.64	4.12	4.32
Complacency (mean)	4.88	5.19	4.66	4.68
Constraints (mean)	4.46	4.80	4.21	4.23
Calculation (mean)	3.53	3.43	3.72	3.56
Collective responsibility (mean)	5.05	5.13	4.91	5.03
Compliance (mean)	2.93	3.46	2.62	2.57
Conspiracy (mean)	4.46	4.35	4.54	4.54
Female (%)	60.73	61.48	58.28	60.80
Age (%)
20–29	26.86	28.48	26.35	25.59
30–39	31.27	35.42	20.56	30.81
40–49	20.54	21.28	18.56	20.48
>49	21.33	14.81	34.53	23.12
Higher education (%)	73.09	80.67	56.69	71.30
Married (%)	48.94	53.20	41.72	47.36
Working status (%)
Regular employee	42.20	44.18	39.92	41.14
Non-regular  employee	23.55	24.38	24.55	22.54
Unemployed/student/other	34.25	31.45	35.53	36.33
Home country or region (%)
China	25.88	32.19	7.19	–
Korea	31.22	15.89	76.65	–
Taiwan	13.90	17.85	2.20	–
Brazil	6.19	6.26	5.99	–
Western countries	6.60	8.42	1.20	–
Other	16.21	19.39	6.79	–
COVID-19 infection history (%)	4.01	6.53	5.19	1.47

The results of the Poisson regression analysis are presented in Fig. 1 (see Supplementary Table 2 for full results). General vaccination readiness and all of its components except “Calculation” were significantly positively associated with COVID-19 vaccine acceptance among all three groups. Significant relationships between “Calculation” and vaccine intentions were found only among foreign-born and Japan-born immigrants.

Fig. 1.

Disparity in association of COVID-19 vaccination readiness and acceptance by migratory status. Note. The rate ratio of vaccine acceptance was adjusted for sex, age, education, marital status, working status, home country or region (only for immigrant groups), and history of COVID-19 infection. A seemingly unrelated regression test was applied to examine the differences in the estimated rate ratios between groups. Significant group differences (p < .05) are indicated with superscripts: (a) foreign-born immigrants vs. Japanese, (b) Japan-born immigrants vs. Japanese, and (c) foreign-born vs. Japan-born immigrants. See the supplementary material for bivariate correlations between vaccination readiness and acceptance.

The result of SUEST showed that the effects of all the readiness components on vaccination acceptability among foreign-born immigrants differed from those of the Japanese, except for “Calculation.” Furthermore, except for “Calculation” and “Compliance,” the effects of the readiness components also differed between foreign-born and Japan-born immigrants. However, a significant difference in effect between the Japan-born immigrants and the Japanese was only found in “Conspiracy.”

4. Discussion

This study explored the differences in COVID-19 vaccination acceptance and its psychological determinants among foreign-born immigrants, Japan-born immigrants, and host population in Japan. Our survey shows that the intentions to receive the COVID-19 vaccine among immigrant participants were approximately the same (Japan-born) or even higher (foreign-born) than those of Japanese participants. Foreign-born immigrants reported the highest score for general COVID-19 vaccination readiness. However, the vaccination coverage among immigrant participants was lower than that of the Japanese participants, especially among those born in Japan, who reported the lowest coverage. This result suggests that immigrants may be experiencing a delay in COVID-19 vaccination behavior—they intended to get vaccinated, but did not or could not do so immediately. The low immunization rates among Japan-born immigrants may be due to their lower trust in the safety and effectiveness of the vaccine and Japanese health authorities. Low belief in vaccine effectiveness is associated with vaccine delays [18], with Japan-born immigrants reporting the lowest score for “Confidence” compared to other groups. Furthermore, barriers such as inflexibility of time and difficulties in scheduling the vaccination appointments, which may be due to low levels of integration, may have hindered vaccination actions among immigrants (Supplementary Fig. 1).

We found that the association between vaccination readiness and acceptance among foreign-born immigrants was significantly different from that among the Japanese. However, the psychological determinants of Japan-born immigrants were more similar to those of Japanese participants than those of immigrants born overseas. This may be because immigrants born in Japan and the Japanese have been raised in the same society and are likely to share perspectives on vaccination.

Among seven components of vaccination readiness, the effects of trust in the safety and effectiveness of vaccines and health authorities (confidence), perceived risk (complacency), and barriers (constraints)—3C model components [19] —on COVID-19 vaccine intentions were strong regardless of the migratory status. However, Japan-born immigrants reported the lowest scores on all three components, which may contribute to the disparity in COVID-19 vaccination coverage and acceptance between them and the other two groups.

In contrast, the rate ratios of “Calculation,” “Compliance,” and “Conspiracy” were relatively low among all three groups. This tendency was similar to the results of previous studies [8], [10]. However, “Calculation” was negatively related to vaccination acceptance in our study. Although the rate ratio of “Compliance” among foreign-born immigrants was slightly lower than that of the Japanese participants, it differed relatively little from other components’ rate ratios compared to that of the Japanese participants. Although vaccination is voluntary in Japan, it may be mandatory in disguise in some immigrants’ home countries. For instance, in China, the national government emphasized that COVID-19 vaccination should be voluntary; however, in practice, many local governments promoted vaccination rates by restricting the behavior of the unvaccinated (e.g., not being allowed into schools). In Korea, for a time citizens were required to show their official COVID-19 vaccine records to enter public places such as restaurants and supermarkets. These social norms in the immigrant’s home country may be transmitted to the immigrant through social media or family or friends and thus influence their vaccination intentions. Those who take for granted their vaccination behavior and punishment for noncompliance may be more likely to receive the vaccination. Additionally, the effect of conspiratorial thinking was stronger among Japanese participants than among immigrants, indicating that countermeasures to vaccine-related conspiracy theories in health education may be more effective among the Japanese population.

Moreover, we found that collective responsibility had a stronger effect on the vaccination intentions of Japan-born immigrants and Japanese participants than among foreign-born immigrants. This result suggests that vaccination promotion campaigns emphasizing collective importance may be more effective among people who have more social connections in society (i.e., Japan-born immigrants and Japanese). As collective responsibility is a willingness to protect others [9], more social ties in the host country may increase the desire to protect others and the number of people who want to protect. Therefore, strengthening the social ties of foreign-born immigrants to the host population may boost their protective motivation, thereby increasing their vaccination acceptance.

As most studies on disparities in vaccination intentions between immigrants or ethnic/racial minorities and the host population immigrants were based in Western countries [20], our study—the first study exploring the difference in COVID-19 vaccination readiness, intentions, and coverage between the immigrant and host population in Japan—contributes significantly to understanding health disparities in the Asian context. However, this study has a few limitations. First, our participants were recruited from an online survey panelist network, and hence, it was a non-probability sample. Individuals with higher education and good language skills—immigrants with higher levels of integration—were likely to be overrepresented. Because highly integrated immigrants have a higher willingness to receive COVID-19 vaccination, the vaccination acceptance rates among the participants of our survey may be higher than that of the actual immigrant population in Japan [14]. As little information or official statistics on the vaccination status of foreign residents in Japan is available, our study has important evidentiary value with regard to the health disparities between immigrants and the host population in Japan.

Second, we divided the immigrant participants into the Japan-born and foreign-born groups. Considering that the psychology and behavior of foreign-born immigrants who came to Japan at a very young age may be similar to that of Japan-born immigrants, classifying them into one group would have been preferable. However, this was not done as they were a small group, and we did not ask the participants about their exact age of arrival in Japan. Nevertheless, when the data were reclassified to include those under 10 years old when they came to Japan and those who had been in Japan for more than 40 years in the category of Japan-born immigrants, the results of the Poisson regression analysis were consistent with our current results (Supplementary material). Third, as the English version of the questionnaire was an auxiliary option, we only pilot-tested different versions of the questionnaire, rather than translation and back-translation strategies, to ensure that questions in other languages reproduced the same meaning. Furthermore, we did not use the validated Japanese version of 7C Scale because the 7C Scale was published at a later phase of our survey design and the validated Japanese version was unavailable at the time of our survey [11]. Nevertheless, our translation was very similar to the official version (Supplementary Table 4).

To conclude, COVID-19 vaccination readiness, acceptance, and its determinants differed according to migratory status and nativity. Immigrant participants had higher COVID-19 vaccination intentions than the Japanese participants, but had lower vaccination coverage, especially those who were born in Japan. As interventions can facilitate vaccination directly [21], measures focused on the 3C model (i.e., confidence, complacency, and constraints) may be effective in promoting the COVID-19 vaccine uptake among immigrants in Japan. Meanwhile, greater efforts aimed at improving the integration of immigrants, such as strengthening their social ties in the host country, may increase their protective motivation, and thus facilitate their vaccination acceptance and uptake. Additionally, higher levels of integration may lead to timely vaccination actions by increasing time flexibility and reducing difficulties in scheduling vaccination appointments. Our findings have practical implications for policymakers and practitioners in public health, and underline the importance of culturally customized vaccination promotion for immigrants.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplementary material

The following are the Supplementary data to this article:

Data availability

Data will be made available on request.