The COVID-19 pandemic is an ongoing threat [1]. COVID-19 vaccination and other behavioral preventive measures can help to eradicate this pandemic. The Hong Kong government procured 2 types of COVID-19 vaccines (Sinovac-Biotech and BioNTech-Fosun Pharma) and implemented a free-of-charge territory-wide vaccination program to all Hong Kong residents aged 16 years or older. The vaccination services were provided through community vaccination centers, designated public and private clinics, and outreach vaccination services at residential care homes or nursing homes [2]. The program aimed to cover the entire Hong Kong population. During the study period (May 1-31, 2021), priorities to receive COVID-19 vaccination were given to the following groups of Hong Kong residents: (1) individuals aged 30 years or older and caregivers of older adults aged more than 70 years; (2) personnel in health care settings and those participating in antiepidemic-related work; (3) residents and staff of residential care homes for the older adults/persons with disabilities; (4) personnel maintaining critical public services; (5) those providing cross-boundary transportation or working at control points/ports; (6) staff of food and beverage premises; (7) staff of local public transportation operators; (8) registered construction workers; (9) staff of property management; (10) teachers and school staff; (11) staff of tourism industry; (12) staff of scheduled premises under the Prevention and Control of Disease Regulation (eg, staff of fitness centers, beauty parlors); (13) students studying outside Hong Kong (aged 16 years or older); and (14) domestic helpers [2]. The latest estimate shows that at least 70% immune individuals would be necessary to achieve herd immunity for COVID-19 [3]. The number of people who received at least one dose of COVID-19 vaccine increased from 936,400 on May 1, 2021 to 1,379,400 on May 31, 2021, accounting for 12.3% and 18.2% of the entire population in Hong Kong, respectively [4]. However, it will take about 1 year for Hong Kong to achieve herd immunity based on the current progress.

Across countries, COVID-19 pandemic continues to have a disproportionate effect on ethnic minorities, with higher COVID-19 morbidity and mortality and greater adverse socioeconomic consequences [5]. With mass COVID-19 vaccination programs in progress, disparities in its uptake may aggravate the vulnerability of ethnic minorities. Across countries, greater vaccine hesitancy has been observed among people from some ethnic minorities [5-7]. In the United Kingdom, vaccine hesitancy was higher among Black, Bangladeshi, and Pakistani people compared with people from a White ethnic background [8]. Two other studies reported lower COVID-19 vaccine uptake rates among ethnic minorities who were older than 80 years (20.5% among Black people vs 42.5% among White people) and those who were health care workers (70.9% White people, 58.5% South Asians, and 36.8% Black people) [9,10]. It is hence important to understand and address the disparities in COVID-19 vaccination among ethnic minorities.

In Hong Kong, the ethnic minority population increased significantly by 70.8% from 2006 to 2016 and accounted for 8.0% (n=584,383) of the entire population (Census, 2016) [11]. After excluding foreign domestic helpers (most of them are Filipinos and Indonesians), South Asians, including Indians, Pakistanis, Nepalis, Bangladeshis, and Sri Lankans make up the largest proportion of the ethnic minorities in Hong Kong (n=85,875, accounting for 1.2% of the entire Hong Kong population) [11]. A recent study found that health system responsiveness reported by South Asians was lower than that reported by Chinese patients for both outpatient and inpatient services in Hong Kong [12]. The largest disparity in the responsiveness was shown in the communication barriers experienced by South Asians owing to cultural and language differences between South Asian patients and local health care service providers [12]. During hospitalization, South Asian inpatients perceived limited access to community support in comparison with the Chinese inpatients [12]. There is also a lack of autonomy in decision-making and choice of health care providers experienced by South Asians [12]. Health professionals in Hong Kong also indicated barriers in their delivery of services to the ethnic minorities, including inadequate dissemination of appropriate information, insufficient provision of cross-cultural care education and training, inadequate availability of public primary care services, and presence of bias and discrimination among hospital staff [12]. Cultural differences between ethnic minorities and health service providers affect patient-provider interactions and health care quality, resulting in mistrust of government and health authorities, which in turn becomes an obstacle for the COVID-19 vaccination program [5]. With an increasing population of South Asians in Hong Kong, it is necessary to plan for COVID-19 vaccination promotional strategies that cater to their unique needs.

This study applied the socioecological model as the conceptual framework, which considered determinants of a health behavior at the individual, interpersonal, and sociostructural levels [13]. An intervention addressing factors at multiple levels is more likely to be successful in changing behavior [13]. At the sociostructural level, previous studies have pointed out the association between cultural/religious belief and COVID-19 vaccine hesitancy. A Malaysian study showed that 20.8% and 6.8% of the ethnic minorities believed that their COVID-19 vaccine hesitancy was caused by concerns regarding religious and cultural factors, respectively [14]. News reports also suggested that there were concerns among Muslims over the halal status of the COVID-19 vaccine [15], and the beliefs that COVID-19 should be healed by God and the body is sacred were cited as reasons to refuse the COVID-19 vaccine [16]. Because a large percentage of the South Asians in Hong Kong are Muslims, there is a need to understand the effects of religious beliefs on COVID-19 vaccine uptake, so that policymakers can target this specific population for the relevant COVID-19 vaccine promotional strategy. Limited evidence is available to date to inform us on the cultural effect of COVID-19 vaccine uptake in Hong Kong.

At the interpersonal level, misinformation related to COVID-19 vaccination threatened vaccine uptake [17]. The government used to report deaths after COVID-19 vaccination, regardless of the existence of the direct causality evidence. Such information exposure might inhibit the motivation to receive COVID-19 vaccination among South Asians as they will associate COVID-19 vaccination directly with deaths. For example, public’s concerns about vaccine safety increased substantially after media reported deaths after COVID-19 vaccination, which resulted in a drop in the proportion of people turning up for their vaccination appointment in Hong Kong (from >90% to 72%) [2]. However, communication with peers may be effective among South Asians owing to higher level of rapport between people of the same ethnicity [18]. The Social Learning Theory posits that observation of peers has a major influence on people’s health behaviors. Therefore, vaccinated peers may play important roles as volunteers in future programs promoting COVID-19 vaccination among South Asians by sharing their positive experience. Peers’ experiences related to COVID-19 vaccination might have a strong influence on South Asians’ decision to receive such vaccinations. Based on these observations, socialization, in terms of receiving vaccine-related information or interpersonal interaction, is assumed to affect vaccine uptake.

At the individual level, the Theory of Planned Behavior (TPB) postulates that in order to perform a behavior, one would evaluate the pros and cons of the behavior (positive and negative attitudes), consider whether their significant others would support such behavior (perceived subjective norm), and appraise how much control one has over the behavior (perceived behavioral control) [19]. The TPB was commonly used to explain a health behavior and guide the behavioral intervention [20,21]; it has been used to explain willingness to receive COVID-19 vaccination among Chinese people [22]. Studies conducted among the Hong Kong general population identified the perceived pros and cons that were associated with the willingness to receive COVID-19 vaccination. Pros included perceived greater risk and severe consequences of infection, perceived higher effectiveness of COVID-19 vaccines, perceived greater impact of COVID-19 vaccination in pandemic control, perceived larger proportion of general public and acquaintance would take up such vaccination, being recommended by physicians and family members, and perceived higher behavioral control to take up the vaccination [23-26]. Concerns related to side effects and access issues as well as difficulties in choosing one out of the available COVID-19 vaccines were commonly mentioned as cons against vaccination [23-26]. These perceptions were considered by this study. To our knowledge, there is a dearth of studies investigating the determinants of COVID-19 vaccine uptake among ethnic minorities in the Asian region. To address the knowledge gaps, this study investigated the prevalence of COVID-19 vaccine uptake among a sample of South Asians in Hong Kong. We examined the effects of factors, including sociodemographic data, and all 3 levels of factors based on the socioecological model.

To our knowledge, this is one of the first studies investigating the determinants of COVID-19 vaccine uptake by using the socioecological perspective among ethnic minorities. About one-third of the participants received at least one dose of COVID-19 vaccination. Factors at the individual level (perceptions related to COVID-19 vaccination), interpersonal level (influence of social media), and sociostructural level (cultural belief) were determinants of the COVID-19 vaccine uptake. Using the socioecological model allows us to understand COVID-19 vaccination behaviors from a comprehensive perspective.

Participants aged 30-49 years reported the highest COVID-19 vaccine uptake; this finding was different from that reported in the Chinese population [23-26]. Married or cohabitation with a partner was also associated with higher COVID-19 vaccine uptake. Future studies should confirm whether protecting one’s partner is the motivation to receive COVID-19 vaccination. In addition, South Asians who were not Hong Kong permanent residents reported lower COVID-19 vaccine uptake. Nonpermanent residents might be less familiar with the health care system in Hong Kong and should receive more support in future programs. As for COVID-19 preventive behaviors, similar to that reported in previous studies [19,22], higher compliance to personal preventive behaviors (eg, consistent facemask wearing in public spaces and hand hygiene) and physical distancing behaviors (eg, avoiding social/meal gathering) was associated with higher uptake.

Culturally, our findings also showed that Pakistanis reported significantly lower COVID-19 vaccine uptake compared to Indians. Differences in the religious belief might partially explain this variation. Islam is the major religion for Pakistanis, and news reported concerns about the halal status of COVID-19 vaccines among Muslims [13]. Our findings suggested that some unique strategies should be tailored for South Asians to address cultural and religious reasons for COVID-19 vaccination hesitancy. The results confirmed that concerns about the halal status of COVID-19 vaccines was a barrier for South Asians to take up the vaccines [15]. The government should work with the vaccine manufacturers to clarify whether gelatin, which has been commonly used as a stabilizer for the safety and effectiveness of vaccines during storage and transportation, is a part of the available COVID-19 vaccines. In order to address other cultural or religious issues, future programs should engage community groups, champions and faith leaders, and develop culturally competent interventions.

At the individual level, South Asians shared some similar facilitators as the local Chinese population to receive COVID-19 vaccination, including perceived efficacy of COVID-19 vaccination in protecting themselves and their family members, perceived impacts of COVID-19 vaccination on pandemic control, perceived support from significant others, and perceived behavioral control of taking up COVID-19 vaccination [23-26]. Concerns about side effects and difficulties in choosing the most suitable COVID-19 vaccine were common barriers [23-26]. Therefore, the same health promotion strategies might be useful for both South Asians and Chinese in Hong Kong. In order to prevent the choice overload [21], efficacies and side effects of different COVID-19 vaccines available in Hong Kong can be compared on a table, which makes it easy for participants to compare features across products [21]. Laymen’s terms in participants’ native language should be used to emphasize that severe side effects of COVID-19 vaccination are rare, and the pros of vaccination outweigh its cons. Testimonials of people who received different types of COVID-19 vaccines regarding side effects should be presented. Health communication messages should also demonstrate that the procedures to receive vaccination are easy and convenient to reduce concerns regarding vaccination procedures. The recommendation made by health care providers is a strong facilitator of COVID-19 vaccine uptake [23-26]. Performing outreach vaccination services in South Asian communities is also useful for enhancing their perceived behavioral control. The results also supported a significant influence of peers on COVID-19 vaccine uptake among South Asians. Updated information about how many South Asians had received COVID-19 vaccination should be disseminated to this group. At the interpersonal level, exposure to negative information about COVID-19 negatively affects vaccine uptake. Health authorities in Hong Kong should identify and address common misinformation in a timely manner. It is encouraging that the government has started to clarify this misinformation on the vaccination program webpage.

The findings of this study should be interpreted in light of some limitations. First, a direct measure of perceived behavioral control should assess self-efficacy and perceived controllability [29,30]. Previous studies have suggested that these 2 constructs were differently associated with behavioral intention and actual behaviors [29,30]. In this study, the scale measuring perceived behavioral control was adapted from a validated tool [19]. Owing to the limited length of the questionnaire, the measurement only had 2 items and mainly covered self-efficacy. Failure to measure perceived controllability together with self-efficacy was one major limitation of this study. Second, in the absence of a sampling frame, participants were conveniently recruited online. Similar to other web-based surveys, the response rate was relatively low (about 25%). We were not able to obtain the characteristics of the active WhatsApp contacts who did not respond to our invitation or refused to complete the survey. Therefore, we were not able to compare the characteristics of the respondents and nonrespondents. There was a selection bias. Generalizations should be made cautiously to South Asians in Hong Kong. Yet, because ethnic minorities is a special population in Hong Kong, using the traditional randomly sampling method of telephone or mail survey was not feasible for administering the questionnaire to this targeted population. Third, some items and scales used in this study were single items, self-constructed, or modified from those used in published studies in the general population. We purposely decided not to use standardized western scale measurements to account for the cultural variations experienced by the ethnic minorities in Hong Kong. A self-constructed or modified scale that is designed to suit the local context of Hong Kong is more suitable. Furthermore, the use of a single-item scale will significantly decrease the burden of the respondents who need to take time to complete the survey. Moreover, this was a cross-sectional study and could not establish causal relationships.

Using the socioecological model, this study offered an overview for us to identify tapping points that can encourage COVID-19 vaccine uptake among South Asian populations in Hong Kong. Because they shared cultural and social orientations dissimilar from those of the local Chinese in Hong Kong, current empirical evidence offered a guide on how promotional strategies can be customized for this population. We recommend religion-targeted, outreach community, and peer-based programs to enhance COVID-19 vaccine uptake rate among South Asians in Hong Kong. To further customize the promotion, these programs can be co-designed, shared, and endorsed by South Asian communities such as nonprofit groups, champions, and faith leaders to develop culturally competent interventions.