Predicting Influenza Vaccination Intent Among At-Risk Chinese Older Adults in Hong Kong Doris S. F. Yu ▼ Lisa P. L. Low ▼ Iris F. K. Lee ▼ Diana T. F. Lee ▼ Wai Man Ng
Background: Older adults with major chronic illnesses are very susceptible to influenza and its serious complications, but many do not obtain vaccinations. Little is known about factors associated with intention to obtain influenza vaccination among at-risk Chinese older adults in Hong Kong. Objectives: The aim of this study was to identify factors associated with intent to obtain influenza vaccination among at-risk Chinese older adults in Hong Kong. Methods: This multicenter descriptive correlational study recruited a convenience sample of 306 Chinese older adults with medical risk factors for influenza and its serious complications from the general outpatient clinics in Hong Kong. Interviews were conducted to assess intent to obtain influenza vaccination for the coming year, health beliefs about influenza, and discomfort following past vaccinations. Results: The current influenza vaccination rate was 58.5%; only 36.3% intended to get vaccinated the following year. After controlling for clinical and demographic factors in a logistic regression model, perceived susceptibility predicted intention to obtain future vaccination (OR = 1.42, 95% CI [1.14, 1.78]), whereas postvaccination discomfort was negatively associated with intention (OR = 0.063, 95% CI [0.006, 0.63]). Conclusions: Intention to obtain influenza vaccination was low among at-risk Chinese older adults. Strengthening health beliefs and creating strategies to provide positive influenza vaccination experiences are possible approaches to interventions to improve uptake of influenza vaccination rates. Key Words: aged • health beliefs • human influenza • theory of planned behavior • vaccination Nursing Research, July/August 2014, Vol 63, No 4, 270–277
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nfluenza is a highly contagious, but preventable, viral respiratory disease affecting 5%–30% of the population worldwide (World Health Organization [WHO], 2012). Annual influenza epidemics result in about 3 million to 5 million cases of severe illness and about 250,000 to 500,000 deaths (WHO, 2009). Advanced age and the presence of certain chronic medical illnesses (e.g., chronic heart, lung, kidney, liver, blood, diabetes mellitus, or immunosuppressive diseases) are important risk factors that increase susceptibility to in fluenza and its serious complications (WHO, 2009). There is high prevalence of influenza among Chinese older adults with chronic disease in Hong Kong (53.3%–56.4% per 100,000 patients; Wong et al., 2006). In Hong Kong, this vulnerable group also has the highest influenza-related hospital admission (admission rate = 2.6 per 10,000 of the population per week; Centre for Health Protection, 2010). Vaccination is the principal preventive measure for influenza. There is substantial evidence to suggest that vaccination Doris S. F. Yu, PhD, RN, is Associate Professor; Lisa P. L. Low, RN, RHV, MPhil, PhD, is Professional Consultant; Iris F. K. Lee, PhD, RN, is Associate Professor; Diana T. F. Lee, RN, RM, PhD, is Director/Chair Professor of Nursing; and Wai Man Ng, RN, MSc, is Registered Nurse, The Nethersole School of Nursing, The Chinese University of Hong Kong. DOI: 10.1097/NNR.0000000000000028
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has an extended beneficial effect that reduces hospitalization as well as all-cause mortality among older adults with chronic medical illnesses (Jefferson et al., 2005; Nichol et al., 2003; Schooling et al., 2012; Wang, Wang, Lai, Lin, & Chou, 2007). Promoting vaccination uptake among older adults with chronic illness is thus an important public health activity. Yet, influenza vaccination status among this at-risk group is often suboptimal (Landi, Onder, Carpenter, Garms-Homolova, & Bernabei, 2005; Li, 2010; Nichol, Nordin, Mullooly, & Lask, 2004). Preventive care has been described as consisting of two phases: intention and actual behaviors (Schwarzer, 2001). For influenza vaccination uptake, factors associated with actual vaccination have been studied among the general older population in Chinese and Western societies (Chi & Neuzil, 2004; Gallaher & Povey, 2006; Kwong, Lam, & Chan, 2009; Lau, Lau, & Lau, 2009; Lau, Yang, Tsui, & Kim, 2006; Tabbarah et al., 2005; Zimmerman et al., 2003). Most of this research followed the postulations of the health belief model (Becker et al., 1977). These studies found that older adults were more likely to have vaccinations if they perceived that they had high susceptibility to influenza (Tabbarah et al., 2005; Zimmerman et al., 2003) and its serious health consequences (Chi & Neuzil, 2004; Tabbarah et al., 2005). As well, perceiving the vaccination as beneficial was associated with obtaining this preventive care Nursing Research • July/August 2014 • Volume 63 • No. 4
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(Kwong et al., 2009; Zimmerman et al., 2003). Some studies also identified advice from health professionals as a cue that prompted influenza vaccination (Kwong et al., 2009; Lau et al., 2006).
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to study factors influencing vaccination intent among the atrisk older adults in a variety of cultures. This addressed the research gap about predictors of influenza vaccination intent among the at-risk Chinese older adults.
Purpose
Vaccination is the principal preventive measure for influenza. Sociodemographic characteristics, including living alone, being strained financially, and having an unfavorable health perception were related to not obtaining influenza vaccination (La Torre, Iarocci, Cadeddu, & Boccia, 2010; Peña-Rey, PérezFarinós, & Sarría-Santamera, 2004; Telford & Rogers, 2003). Less is known about factors associated with intent to receive influenza vaccine. The theory of reasoned action (TRA) has provided important insights, however (Ajzen & Fishbein, 1980). The TRA postulates that the likelihood for performing preventive care is strongly determined by an individual’s intention to engage in that behavior (Ajzen & Fishbein, 1980). This theory is useful for predicting behaviors under perceived control like influenza vaccination (Glanz, Rimer, & Viswanath, 2008). Similar to the health belief model, such intention is determined by one’s belief about the health actions and the disease consequences, but the TRA also highlights the role of subjective norm in shaping the intention. Subjective norm refers to one’s belief about the other’s expectation of them to perform a health action. For influenza vaccination, the subjective norm may be shaped by the health messages received from the healthcare professionals, family, or mass media. Hamilton and White (2008) further extended the TRA to include the influence of past experience in shaping intention to action. A meta-analysis on factors affecting the vaccination behavior identified current vaccinated status as a prominent predictor for positive vaccination intent in the following year (Nagata et al., 2013). However, such relationships would be affected by previous vaccination experiences. In particular, postvaccination discomfort was identified as a strong force to discourage future influenza vaccination (Armstrong, Berlin, Schwartz, Propert, & Ubel, 2001). Culture has been identified as a social determinant of influenza vaccination (Nagata et al., 2013). In particular, people with cultural beliefs that emphasize indigenous health practices were found to be more reluctant to receive vaccination. Such cultural belief and practices are prominent among Chinese older adults. A cross-cultural study found that Chinese people valued naturalism, and they tended to trust indigenous health practices such as steaming vinegar and herbs, taking Chinese herbal tea or garlic, keeping warm, and avoiding cold drinks and food as self-care measures for preventing influenza (Kwong, Pang, Choi, & Wong, 2010). It is, therefore, important
The overall aim of this study was to identify the factors that predicted influenza vaccination intent in the upcoming year among Chinese older adults with medical risk status for influenza and its serious complications. The two specific study objectives are to (a) examine health beliefs of the at-risk Chinese older adults and (b) identify predictors of influenza vaccination intent from health beliefs, current influenza vaccination status, and previous vaccination-related discomfort.
METHODS Setting and Participants This was a multicenter, cross-sectional correlational study. Data were collected between February and July 2011 in three general outpatient clinics (GOPCs) in Hong Kong. The GOPCs are a major public health sector in Hong Kong; over 35% of its users are older adults, of whom 63% have chronic illnesses (Wong et al., 2010). A convenience sample of communitydwelling older adults was recruited. Eligible participants were those who were of ages 65 or above, who had medical risk status for influenza and its serious complications, who were able to communicate verbally, who were with no cognitive impairment (i.e., Mini-Mental State Examination Score > 19/30), and who consented to participate. A power analysis was conducted to determine the sample size needed to ensure there was adequate statistical power when using logistic regression to identify the predictive factors of influenza vaccination uptake. Following the event-to-variable ratio of 20 for logistic regression analysis (Harrell, Lee, & Mark, 1996), a sample size of at least 280 was required to identify the predictive factors of influenza vaccination uptake among 14 potential predictive factors identified in the literature at 80% power with the level of significance set at .05 (as listed in Table 1).
Variables and Measurement Health Beliefs About Influenza Vaccination The Chinese version of Hämmig’s (1998) questionnaire (as cited in Mok, Yeung, & Chan, 2006)was used to measure the health beliefs toward influenza vaccination (Mok et al., 2006). It measures four aspects of health beliefs toward influenza vaccination, including perceived susceptibility (four items), perceived severity (five items), perceived benefits (seven items), and perceived barriers (four items). The four Likert-type response options ranged from 1 (strongly disagree) to 4 (strongly agree). The possible range of scores is 20–80, with a higher score indicating a more positive health belief. The reliability of the Hämmig’s questionnaire was reported as .60–.86 when used in the Hong Kong
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Chinese population (Mok et al., 2006). A single item was also used to ask how the participants perceived their own health. Five response options were used: “poor,” “not good,” “fair,” “good,” and “very good.”
TABLE 1. Participant Characteristics: Total Sample
Demographics, Clinical Data, and Vaccination Status
Ethics approval was obtained from the clinical ethics committee. After receiving the consent forms, the research nurse screened the cognitive eligibility of the subjects with MiniMental State Examination Score. For those who met all the selection criteria, the research nurse conducted face-to-face interviews to collect data on health beliefs toward influenza vaccination (Hämmig’s questionnaire), sociodemographic and clinical data, and vaccination history. The purpose of using face-to-face interviews was to reduce missing data and allow illiterate older adults to participate.
Gender (male) With spouse Number of children 0 1 2 3 –>4 Educational level No formal education Primary level Secondary level or above Living arrangement Alone With spouse With family Financial strain (yes) Medical risk factors for influenza Diabetes mellitus Chronic heart disease Cerebrovascular disease Chronic lung disease Chronic renal disease Chronic liver disease Cancer High comorbiditya Hospital admissionsb None Single Multiplec Perceives self as unhealthy
Statistical Analysis
Note. N = 306. aThree or more chronic diseases. bPrevious year. cTwo or more hospitalizations.
An investigator-developed data collection sheet was used to obtain additional data, including (a) the demographic data (age, gender, marital status, perceived financial strain, living arrangements, educational level); (b) clinical profile (history of chronic medical illnesses, number of hospitalizations in the previous year); (c) perceived health using an ascending 5-point Likert-type scale; (d) current influenza vaccination status (i.e., history of influenza vaccination in the past 12 months); and (e) information about postvaccination discomfort or complications (whether they have intention to be vaccinated in the next 12 months) and related advice on influenza vaccination from family, healthcare professionals, and mass media.
Procedures
Descriptive statistics were used to summarize participant characteristics, vaccination history, health beliefs on influenza vaccination, health perceptions, cognitive functions, and level of impairment in physical functions. Multiple logistic regression with stepwise inclusion of predictors was used to identify the factors that affected influenza vaccination intent. Prior to estimating the logistic regression, t tests for independent groups or chi-square tests for independence were used to identify the variables that differentiated participants who reported an intention to receive an influenza vaccination the following year and those who did not at the univariate level. Predictors with p < .2 in these analyses were entered into the multiple logistic regression analysis as candidate predictors. Regression diagnostics were performed to check whether the data met the statistical assumptions. Hosmer-Lemeshow was used to test the data-model fit (Tabachnick & Fidell, 2007). The candidate variables were entered into the regression model in two blocks. In the first block, the demographic and clinical variables, which were significantly related to vaccination behavior, were force-entered to the logistic regression model to adjust their potential confounding effect. In the
Characteristic Age (years)
M
SD
74.6 n 190 244
6.3 % 62.1 79.7
20 30 90 86 80
6.5 9.8 29.4 28.1 26.1
47 120 139
15.4 39.2 45.4
45 112 149 39
14.7 36.6 48.7 12.7
193 83 35 21 2 3 21 85
63.1 27.1 11.4 6.9 0.7 1.0 6.9 27.8
219 58 29 237
71.6 18.3 9.5 77.5
second block, remaining candidate variables were entered. Significance of the regression coefficients, Wald statistics, odd ratios, and 95% confidence intervals for odds ratio were computed to identify significant predictors. The stepwise criteria of probabilityof-F-to-enter and probability-of-F-to-remove were set at .5 and 1.0, respectively. The nominal level of significance was set at 5%. All statistical analyses were done with an SPSS Version 19 software program.
RESULTS Participant Characteristics During the 6-month study period, the research nurses screened a total of 710 medical records of patients in the GOPD and identified 607 potentially eligible older adults for further screening. Among this group, 336 of them met the selection criteria. A total of 306 older adults participated, with the response rate of 91.1%. Thirty patients refused to participate because they were not interested in joining or had no time. The
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sample mean age was 74.6 (SD = 6.3), with more men (40.3%) than women (39.7%). About half the sample had received primary level education or below, and around 13% reported financial strain. Among the medical risk factors for serious influenza-related complications, diabetes was the most prevalent (63.1%), followed by chronic heart disease (28.4%) and cerebrovascular disease (11.4%). About 27.8% of the older adults had at least three chronic illnesses, and a majority perceived themselves as unhealthy. Table 1 summarizes the clinical and demographic characteristics.
Vaccination Rates and Experiences The current vaccination uptake rate was 58.5%. They received the vaccination at about 2–8 months prior. About 3.9% reported postvaccination discomfort including fever, headache, fatigue, rash, swelling of the injection site, cough, and transient loss of voice. About 17.6% of participants reported getting influenza even after they had been vaccinated. Only about one third of participants (36.3%) reported intention to get the next annual vaccination. Most participants obtained information about influenza vaccination from the mass media (61.1%) or from healthcare professionals (64.1%).
Beliefs About Influenza and Influenza Vaccination Responses to the Hämmig’s questionnaire about health beliefs related to influenza vaccination are reported in Table 2. For
perceived severity, about 32%–42% of the participants did not recognize that flu worsens underlying medical conditions or health problems. Fewer than 40% thought that influenza would cause mortality among older adults. Participants recognized that vaccination can prevent severe influenza among people age 65 or above, but almost 50% did not realize their own increased susceptibility to get influenza if they did not vaccinate. Even fewer agreed with the effect of vaccination on reducing their influenza-related mortality risk. On the other hand, a majority perceived influenza vaccination as beneficial and safe. However, they did not realize the additional advantage of influenza vaccination in reducing their own risks of getting a more severe manifestation of influenza. Almost 70% also denied its positive effects on quality of life and mortality. Unlike previous literature, which identified the time-related or geographically related barriers for vaccination (Lau et al., 2006, 2009), comparatively more participants identified postvaccination sickness and injection-related pain as major hindering factors.
Predicting Influenza Vaccination Intent Of the sample, only 36.4% (n = 111) indicated that they intended to receive vaccination in the following 12 months. Table 3 shows bivariate relationships between patient characteristics and influenza vaccination intent. Eight variables were related to vaccination intent at p < .2. Female gender,
TABLE 2. Beliefs About Influenza and Influenza Vaccination Response Option Item Perceived severity of flu Interference: daily activities Worsens: underlying medical conditions Can be a bad disease Worsens: other health problems Causes death in the elderly Perceived susceptibility With no shot, elderly get more severe flu With no shot, I am likely to get the flu With no shot, my life span shortened I get sick easily Perceived benefit Good for elderly to get flu shot Flu shot benefits society Flu shot prevents flu in elderly Flu shot is safe Flu shot protects me from more severe flu Flu shot improves my quality of life Getting a flu shot lengthens my life span Perceived barriers Hard to access I have gotten sick from a flu shot Shots are painful No time
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SD
D
A
SA
M
SD
5.3 1.3 5.9 3.6 4.9
20.8 30.7 32.4 38.6 56.2
50.9 41.5 32.7 39.5 17.6
23.1 26.5 29.1 18.3 21.2
2.96 2.93 2.85 2.73 2.55
0.81 0.79 0.91 0.80 0.88
1.0 3.9 2.6 38.9
36.6 44.8 58.4 37.6
41.8 36.3 21.6 18.3
20.6 15.0 17.0 5.2
2.82 2.62 2.53 1.90
0.76 0.79 0.80 0.88
1.6 1.6 1.0 3.3 1.6 6.2 10.1
4.6 8.2 26.5 25.2 34.3 64.7 65.4
50.3 45.8 45.4 47.1 42.5 22.2 17.6
43.5 44.4 27.1 24.5 21.6 6.9 6.9
3.36 3.33 2.99 2.93 2.84 2.30 2.21
0.65 0.70 0.76 0.79 0.78 0.69 0.71
2.6 31.0 39.5 68.0
3.9 47.4 45.1 24.8
36.3 18.0 11.4 5.6
57.2 3.6 3.9 1.6
3.48 1.94 1.80 1.41
0.70 0.80 0.79 0.67
Note. N = 306. Cell entries are percent selecting each response option. SD = strongly disagree; D = somewhat disagree; A = somewhat agree; SA = strongly agree.
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TABLE 3. Characteristics of Participants With and Without Intention to Receive Influenza Vaccination Vaccination Intention Yes (n = 111) Characteristic Age Health beliefs Perceived severity Perceived susceptibility Perceived benefit Perceived barrier
Gender (male) With spouse (yes) Living arrangement Living alone With spouse With family Financial strain (yes) Comorbiditiesa Perceives self as unhealthy (yes) Advice: influenza vaccination From family (yes) From mass media (yes) From healthcare professionals (yes) Had current influenza vaccination (yes) Past postvaccination discomfort (yes)
No (n = 195)
M
SD
M
SD
p
74.2
5.5
73.9
7.0
.27
15.14 11.34 21.82
3.01 2.37 3.05
13.39 9.04 18.89
2.82 1.91 2.83
6.05
1.94
7.02
1.68
.01 .01 .01 .01
n
%
n
%
61 86
55.0 77.5
129 158
66.2 81.0
.05
16 40 55 13 44 87
14.4 36.0 49.5 11.7 39.6 78.4
29 72 94 26 41 150
13.8 36.9 48.2 13.3 21.0 76.9
.27
20 68 67 97 1
18.0 61.3 60.4 87.4 1.0
34 119 129 82 7
17.4 61.0 66.2 42.1 7.0
.43 .46 .31 .001 .03
.43 .001 .44
Note. N = 306. aThree or more chronic disease comorbidities.
presence of multimorbidity, greater perceived susceptibility to influenza, greater perceived disease severity, and greater perceived benefit were positively associated with a greater intention to obtain further vaccination. Perceived barriers, on the other hand, had negative effects on intention. Current vaccination status was also positively associated with the intention for further vaccination. About 54.2% of the currently vaccinated participants intended to get vaccinated next year, whereas 89% of the unvaccinated participants did not intend to obtain a vaccination next year (p < .001). All except one participant (n = 8) who experienced postvaccination discomfort did not intend to have future vaccination. All eight variables were entered into the logistic regression model, which significantly predicted the intention for future vaccination (omnibus test of model coefficients, p< .001). Results are summarized in Table 4. After controlling for the confounding effects of gender and multiple comorbidities, higher perceived susceptibility (OR = 1.42, 95% CI [1.14, 1.78]) independently predicted intention of future vaccination, whereas the experience of postvaccination discomfort was negatively associated with intention to be vaccinated (OR = 0.63, 95% CI [0.006, 0.633]).
DISCUSSION This is the first study to examine the influenza vaccination intent among Chinese older people who are at risk for influenza
and its serious complications. Although an intention for action has been regarded as a strongest predictor of behavior (Ajzen & Fishbein, 1980), only 36.3% of this group of at-risk Chinese older adults intended to receive influenza vaccinations in the following 12 months. Indeed, the results also identified the suboptimal current influenza vaccination status among this high-risk group by referencing to WHO recommendations (i.e., 75% vaccination rate among the at-risk population; WHO, 2012). Indeed, the vaccination rate was even lower than that in the general older population residing in the same city (i.e., 64%; Kwong et al., 2009). The findings conform to the reported disparities in the medical risk status and the influenza vaccination TABLE 4. Predictors of Intention for Future Vaccination Predictor Control variable Gender Multimorbidity Predictive variable Perceived severity Perceived susceptibility Perceived benefit Perceived barrier Current vaccination Postvaccination discomfort
B
SE
p
OR [95% CI]
0.59 0.82
.35 .37
.09 .03
1.80 [.92, 3.55] 2.27 [1.11, .66]
0.09 0.35 −0.03 −0.16 0.69 −2.76
.07 .11 .09 .11 .53 1.17
.21 1.09 [.95, 1.24] .002 1.42 [1.14, 1.78] .73 0.97 [.81, 1.16] .13 0.85 [.69, 1.05] .20 1.99 [.70, 5.61] .02 0.063 [.006, .63]
Note. N = 306.
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rate for the Western population (Nichol et al., 2004; Landi et al., 2005; Li, 2010). In fact, participants in this study were in regular contact with healthcare professionals to manage their chronic medical illnesses. Such a suboptimal influenza vaccination status and intent deserves prompt attention from healthcare services in protecting this at-risk group against influenza and its serious complications. Health beliefs and past vaccination experiences had significant roles in determining the influenza vaccination intent among the at-risk Chinese older adults in our sample. For health beliefs, not realizing their own increased susceptibility to influenza, resulting from the synergistic effects of old age and medical risk factors, was highly prominent in reducing their vaccination intent. Such low vaccination intention was also related to their inadequate awareness of the additional benefits of influenza vaccination, which prevent them from getting severe flu and developing serious complications, including mortality. Such health belief, indeed, has been identified in international studies as prominently affecting the influenza vaccination behaviors among the general older population (Chi & Neuzil, 2004; Kwong et al., 2009; Lau et al., 2006; Tabbarah et al., 2005; Zimmerman et al., 2003). This study extends the existing knowledge and indicates the additional role of such health beliefs in affecting the vaccination intent. Conforming to the TRA and previous findings, this study suggests the significant impact of past experience in influencing the influenza vaccination intent of at-risk Chinese older adults (Armstrong et al., 2001; Nagata et al., 2013). The findings indicate that almost 90% of unvaccinated at-risk Chinese older adults had no intention for influenza vaccination in the forthcoming year. Encouraging influenza vaccination among this at-risk group may then result in a “carryover” effect to encourage vaccination in the subsequent year. However, older adults’ experiences in previous vaccination also play an important role in affecting this carryover effect. In particular, these findings suggest that postvaccination discomfort discouraged vaccination intent. Although the incidence of the postvaccination discomfort was very low among this at-risk group (i.e., 3.9%), some reported complaints (e.g., cough, transient loss of voice) might just occur coincidently with the vaccination, and its impact on the vaccination intent should not be taken for granted. Then again, the study did not identify the influence of health messages from different sources on influenza vaccination intent. The influence of subjective norm on intention might be less prominent in the context of influenza vaccination. An alternative explanation might also be related to the fact that such health messages were mainly delivered during the peak seasons for influenza and emphasized more on urging older adults to receive a current influenza vaccination. The suboptimal influenza vaccination status and the low intention for subsequent vaccination imply a prompt need to promote this crucial preventive care among the at-risk Chinese
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older adults. The need for this high-risk group to attend regular medical follow-up provides a good contact point to promote influenza vaccination. Their low intention implies the importance of setting up a surveillance and client reminder system in the GOPC to monitor the vaccination status of this high-risk group year by year (Ndiaye et al., 2005). The system can generate an automated message when older adults are due for influenza vaccination. Healthcare professionals would remind them to get vaccinated during medical follow-up accordingly. They can clarify any concerns about the vaccination- induced influenza or postvaccination discomfort. Monitoring the older adults’ postvaccination status, such as subsequent influenza, postvaccination discomfort, influenza-related complications, and hospitalization, and entering such information into the surveillance and client reminder system can help to generate important statistics to reflect the positive impact of vaccination. Such local statistics would be of great value for public education. Educative, supportive intervention would be one approach to cultivating a positive health belief toward influenza and its vaccination (Ndiaye et al., 2005). Efforts must be made to educate this high-risk group about the especially deleterious impact of influenza on complicating their medical conditions and the additional benefit of annual vaccination in delimiting the infection and preventing serious complications. To address the workforce constraints in healthcare, broadcasting videobased education in waiting halls could be a cost-effective alternative. Modeling technique by sharing the peers’ positive vaccination experience and presenting a vivid scenario to illustrate the ways to cope with the common barriers (such as fear of pain and postvaccination discomfort) have been suggested as effective to shape health behavioral changes (Krouse, 2001).
Limitations Several methodological issues are worth considering. The use of a cross-sectional study design precludes concluding that predictors cause influenza vaccination intent. Also, influenza vaccination intent was assessed by self-report. The data may have been subjected to social desirability bias when participants reported such information to a research nurse. Finally, influenza vaccination uptake is a complex phenomenon. Using a quantitative research methodology in this study limited the exploration to a set of predetermined factors. Future studies using a qualitative approach are recommended, which would allow identification of novel predictive factors.
Conclusions This study provides important insights into the factors that affect influenza vaccination intent among Chinese older adults at risk of serious influenza-related complications. The study findings reinforce the role of healthcare professionals in encouraging vaccination uptake among this vulnerable group and draw attention to the impact of health beliefs toward influenza and its vaccination.
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Accepted for publication December 26, 2013. The authors have no conflicts of interest to report. Corresponding author: Doris S. F. Yu, PhD, RN, Room 729, Esther Lee Building, The Nethersole School of Nursing, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR (e-mail: [email protected]).
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Telford, R., Rogers, A. (2003). What influences elderly peoples decisions about whether to accept the influenza vaccination? A qualitative study. Health Education Research, 18, 743–753. doi:10.1093/her/cyf059 Wang, C.-S., Wang, S.-T., Lai, C.-T., Lin, L.-J., & Chou, P. (2007). Impact of influenza vaccination on major cause-specific mortality. Vaccine, 25, 1196–1203. http://dx.doi.org/10.1016/j.vaccine .2006.10.015 Wong, C. M., Yang, L., Chan, K. P., Leung, G. M., Chan, K. H., Guan, Y., . . . Peiris, J. S. M. (2006). Influenza-associated hospitalization in a subtropical city. PLoS Medicine, 3, e121. doi:10.1371/ journal.pmed.0030121. Wong, S. Y. S., Kung, K., Griffiths, S. M., Carthy, T., Wong, M. C. S., Lo, S. V., . . . Starfield, B. (2010). Comparison of primary care experiences among adults in general outpatient clinics and
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Background: Older adults with major chronic illnesses are very susceptible to influenza and its serious complications, but many do not obtain vaccinations. Little is known about factors associated with intention to obtain influenza vaccination among at-risk Chinese older adults in Hong Kong. Objectives: The aim of this study was to identify factors associated with intent to obtain influenza vaccination among at-risk Chinese older adults in Hong Kong. Methods: This multicenter descriptive correlational study recruited a convenience sample of 306 Chinese older adults with medical risk factors for influenza and its serious complications from the general outpatient clinics in Hong Kong. Interviews were conducted to assess intent to obtain influenza vaccination for the coming year, health beliefs about influenza, and discomfort following past vaccinations. Results: The current influenza vaccination rate was 58.5%; only 36.3% intended to get vaccinated the following year. After controlling for clinical and demographic factors in a logistic regression model, perceived susceptibility predicted intention to obtain future vaccination (OR = 1.42, 95% CI [1.14, 1.78]), whereas postvaccination discomfort was negatively associated with intention (OR = 0.063, 95% CI [0.006, 0.63]). Conclusions: Intention to obtain influenza vaccination was low among at-risk Chinese older adults. Strengthening health beliefs and creating strategies to provide positive influenza vaccination experiences are possible approaches to interventions to improve uptake of influenza vaccination rates. Key Words: aged • health beliefs • human influenza • theory of planned behavior • vaccination Nursing Research, July/August 2014, Vol 63, No 4, 270–277
I
nfluenza is a highly contagious, but preventable, viral respiratory disease affecting 5%–30% of the population worldwide (World Health Organization [WHO], 2012). Annual influenza epidemics result in about 3 million to 5 million cases of severe illness and about 250,000 to 500,000 deaths (WHO, 2009). Advanced age and the presence of certain chronic medical illnesses (e.g., chronic heart, lung, kidney, liver, blood, diabetes mellitus, or immunosuppressive diseases) are important risk factors that increase susceptibility to in fluenza and its serious complications (WHO, 2009). There is high prevalence of influenza among Chinese older adults with chronic disease in Hong Kong (53.3%–56.4% per 100,000 patients; Wong et al., 2006). In Hong Kong, this vulnerable group also has the highest influenza-related hospital admission (admission rate = 2.6 per 10,000 of the population per week; Centre for Health Protection, 2010). Vaccination is the principal preventive measure for influenza. There is substantial evidence to suggest that vaccination Doris S. F. Yu, PhD, RN, is Associate Professor; Lisa P. L. Low, RN, RHV, MPhil, PhD, is Professional Consultant; Iris F. K. Lee, PhD, RN, is Associate Professor; Diana T. F. Lee, RN, RM, PhD, is Director/Chair Professor of Nursing; and Wai Man Ng, RN, MSc, is Registered Nurse, The Nethersole School of Nursing, The Chinese University of Hong Kong. DOI: 10.1097/NNR.0000000000000028
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has an extended beneficial effect that reduces hospitalization as well as all-cause mortality among older adults with chronic medical illnesses (Jefferson et al., 2005; Nichol et al., 2003; Schooling et al., 2012; Wang, Wang, Lai, Lin, & Chou, 2007). Promoting vaccination uptake among older adults with chronic illness is thus an important public health activity. Yet, influenza vaccination status among this at-risk group is often suboptimal (Landi, Onder, Carpenter, Garms-Homolova, & Bernabei, 2005; Li, 2010; Nichol, Nordin, Mullooly, & Lask, 2004). Preventive care has been described as consisting of two phases: intention and actual behaviors (Schwarzer, 2001). For influenza vaccination uptake, factors associated with actual vaccination have been studied among the general older population in Chinese and Western societies (Chi & Neuzil, 2004; Gallaher & Povey, 2006; Kwong, Lam, & Chan, 2009; Lau, Lau, & Lau, 2009; Lau, Yang, Tsui, & Kim, 2006; Tabbarah et al., 2005; Zimmerman et al., 2003). Most of this research followed the postulations of the health belief model (Becker et al., 1977). These studies found that older adults were more likely to have vaccinations if they perceived that they had high susceptibility to influenza (Tabbarah et al., 2005; Zimmerman et al., 2003) and its serious health consequences (Chi & Neuzil, 2004; Tabbarah et al., 2005). As well, perceiving the vaccination as beneficial was associated with obtaining this preventive care Nursing Research • July/August 2014 • Volume 63 • No. 4
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(Kwong et al., 2009; Zimmerman et al., 2003). Some studies also identified advice from health professionals as a cue that prompted influenza vaccination (Kwong et al., 2009; Lau et al., 2006).
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to study factors influencing vaccination intent among the atrisk older adults in a variety of cultures. This addressed the research gap about predictors of influenza vaccination intent among the at-risk Chinese older adults.
Purpose
Vaccination is the principal preventive measure for influenza. Sociodemographic characteristics, including living alone, being strained financially, and having an unfavorable health perception were related to not obtaining influenza vaccination (La Torre, Iarocci, Cadeddu, & Boccia, 2010; Peña-Rey, PérezFarinós, & Sarría-Santamera, 2004; Telford & Rogers, 2003). Less is known about factors associated with intent to receive influenza vaccine. The theory of reasoned action (TRA) has provided important insights, however (Ajzen & Fishbein, 1980). The TRA postulates that the likelihood for performing preventive care is strongly determined by an individual’s intention to engage in that behavior (Ajzen & Fishbein, 1980). This theory is useful for predicting behaviors under perceived control like influenza vaccination (Glanz, Rimer, & Viswanath, 2008). Similar to the health belief model, such intention is determined by one’s belief about the health actions and the disease consequences, but the TRA also highlights the role of subjective norm in shaping the intention. Subjective norm refers to one’s belief about the other’s expectation of them to perform a health action. For influenza vaccination, the subjective norm may be shaped by the health messages received from the healthcare professionals, family, or mass media. Hamilton and White (2008) further extended the TRA to include the influence of past experience in shaping intention to action. A meta-analysis on factors affecting the vaccination behavior identified current vaccinated status as a prominent predictor for positive vaccination intent in the following year (Nagata et al., 2013). However, such relationships would be affected by previous vaccination experiences. In particular, postvaccination discomfort was identified as a strong force to discourage future influenza vaccination (Armstrong, Berlin, Schwartz, Propert, & Ubel, 2001). Culture has been identified as a social determinant of influenza vaccination (Nagata et al., 2013). In particular, people with cultural beliefs that emphasize indigenous health practices were found to be more reluctant to receive vaccination. Such cultural belief and practices are prominent among Chinese older adults. A cross-cultural study found that Chinese people valued naturalism, and they tended to trust indigenous health practices such as steaming vinegar and herbs, taking Chinese herbal tea or garlic, keeping warm, and avoiding cold drinks and food as self-care measures for preventing influenza (Kwong, Pang, Choi, & Wong, 2010). It is, therefore, important
The overall aim of this study was to identify the factors that predicted influenza vaccination intent in the upcoming year among Chinese older adults with medical risk status for influenza and its serious complications. The two specific study objectives are to (a) examine health beliefs of the at-risk Chinese older adults and (b) identify predictors of influenza vaccination intent from health beliefs, current influenza vaccination status, and previous vaccination-related discomfort.
METHODS Setting and Participants This was a multicenter, cross-sectional correlational study. Data were collected between February and July 2011 in three general outpatient clinics (GOPCs) in Hong Kong. The GOPCs are a major public health sector in Hong Kong; over 35% of its users are older adults, of whom 63% have chronic illnesses (Wong et al., 2010). A convenience sample of communitydwelling older adults was recruited. Eligible participants were those who were of ages 65 or above, who had medical risk status for influenza and its serious complications, who were able to communicate verbally, who were with no cognitive impairment (i.e., Mini-Mental State Examination Score > 19/30), and who consented to participate. A power analysis was conducted to determine the sample size needed to ensure there was adequate statistical power when using logistic regression to identify the predictive factors of influenza vaccination uptake. Following the event-to-variable ratio of 20 for logistic regression analysis (Harrell, Lee, & Mark, 1996), a sample size of at least 280 was required to identify the predictive factors of influenza vaccination uptake among 14 potential predictive factors identified in the literature at 80% power with the level of significance set at .05 (as listed in Table 1).
Variables and Measurement Health Beliefs About Influenza Vaccination The Chinese version of Hämmig’s (1998) questionnaire (as cited in Mok, Yeung, & Chan, 2006)was used to measure the health beliefs toward influenza vaccination (Mok et al., 2006). It measures four aspects of health beliefs toward influenza vaccination, including perceived susceptibility (four items), perceived severity (five items), perceived benefits (seven items), and perceived barriers (four items). The four Likert-type response options ranged from 1 (strongly disagree) to 4 (strongly agree). The possible range of scores is 20–80, with a higher score indicating a more positive health belief. The reliability of the Hämmig’s questionnaire was reported as .60–.86 when used in the Hong Kong
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Chinese population (Mok et al., 2006). A single item was also used to ask how the participants perceived their own health. Five response options were used: “poor,” “not good,” “fair,” “good,” and “very good.”
TABLE 1. Participant Characteristics: Total Sample
Demographics, Clinical Data, and Vaccination Status
Ethics approval was obtained from the clinical ethics committee. After receiving the consent forms, the research nurse screened the cognitive eligibility of the subjects with MiniMental State Examination Score. For those who met all the selection criteria, the research nurse conducted face-to-face interviews to collect data on health beliefs toward influenza vaccination (Hämmig’s questionnaire), sociodemographic and clinical data, and vaccination history. The purpose of using face-to-face interviews was to reduce missing data and allow illiterate older adults to participate.
Gender (male) With spouse Number of children 0 1 2 3 –>4 Educational level No formal education Primary level Secondary level or above Living arrangement Alone With spouse With family Financial strain (yes) Medical risk factors for influenza Diabetes mellitus Chronic heart disease Cerebrovascular disease Chronic lung disease Chronic renal disease Chronic liver disease Cancer High comorbiditya Hospital admissionsb None Single Multiplec Perceives self as unhealthy
Statistical Analysis
Note. N = 306. aThree or more chronic diseases. bPrevious year. cTwo or more hospitalizations.
An investigator-developed data collection sheet was used to obtain additional data, including (a) the demographic data (age, gender, marital status, perceived financial strain, living arrangements, educational level); (b) clinical profile (history of chronic medical illnesses, number of hospitalizations in the previous year); (c) perceived health using an ascending 5-point Likert-type scale; (d) current influenza vaccination status (i.e., history of influenza vaccination in the past 12 months); and (e) information about postvaccination discomfort or complications (whether they have intention to be vaccinated in the next 12 months) and related advice on influenza vaccination from family, healthcare professionals, and mass media.
Procedures
Descriptive statistics were used to summarize participant characteristics, vaccination history, health beliefs on influenza vaccination, health perceptions, cognitive functions, and level of impairment in physical functions. Multiple logistic regression with stepwise inclusion of predictors was used to identify the factors that affected influenza vaccination intent. Prior to estimating the logistic regression, t tests for independent groups or chi-square tests for independence were used to identify the variables that differentiated participants who reported an intention to receive an influenza vaccination the following year and those who did not at the univariate level. Predictors with p < .2 in these analyses were entered into the multiple logistic regression analysis as candidate predictors. Regression diagnostics were performed to check whether the data met the statistical assumptions. Hosmer-Lemeshow was used to test the data-model fit (Tabachnick & Fidell, 2007). The candidate variables were entered into the regression model in two blocks. In the first block, the demographic and clinical variables, which were significantly related to vaccination behavior, were force-entered to the logistic regression model to adjust their potential confounding effect. In the
Characteristic Age (years)
M
SD
74.6 n 190 244
6.3 % 62.1 79.7
20 30 90 86 80
6.5 9.8 29.4 28.1 26.1
47 120 139
15.4 39.2 45.4
45 112 149 39
14.7 36.6 48.7 12.7
193 83 35 21 2 3 21 85
63.1 27.1 11.4 6.9 0.7 1.0 6.9 27.8
219 58 29 237
71.6 18.3 9.5 77.5
second block, remaining candidate variables were entered. Significance of the regression coefficients, Wald statistics, odd ratios, and 95% confidence intervals for odds ratio were computed to identify significant predictors. The stepwise criteria of probabilityof-F-to-enter and probability-of-F-to-remove were set at .5 and 1.0, respectively. The nominal level of significance was set at 5%. All statistical analyses were done with an SPSS Version 19 software program.
RESULTS Participant Characteristics During the 6-month study period, the research nurses screened a total of 710 medical records of patients in the GOPD and identified 607 potentially eligible older adults for further screening. Among this group, 336 of them met the selection criteria. A total of 306 older adults participated, with the response rate of 91.1%. Thirty patients refused to participate because they were not interested in joining or had no time. The
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Influenza Vaccination Intent
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sample mean age was 74.6 (SD = 6.3), with more men (40.3%) than women (39.7%). About half the sample had received primary level education or below, and around 13% reported financial strain. Among the medical risk factors for serious influenza-related complications, diabetes was the most prevalent (63.1%), followed by chronic heart disease (28.4%) and cerebrovascular disease (11.4%). About 27.8% of the older adults had at least three chronic illnesses, and a majority perceived themselves as unhealthy. Table 1 summarizes the clinical and demographic characteristics.
Vaccination Rates and Experiences The current vaccination uptake rate was 58.5%. They received the vaccination at about 2–8 months prior. About 3.9% reported postvaccination discomfort including fever, headache, fatigue, rash, swelling of the injection site, cough, and transient loss of voice. About 17.6% of participants reported getting influenza even after they had been vaccinated. Only about one third of participants (36.3%) reported intention to get the next annual vaccination. Most participants obtained information about influenza vaccination from the mass media (61.1%) or from healthcare professionals (64.1%).
Beliefs About Influenza and Influenza Vaccination Responses to the Hämmig’s questionnaire about health beliefs related to influenza vaccination are reported in Table 2. For
perceived severity, about 32%–42% of the participants did not recognize that flu worsens underlying medical conditions or health problems. Fewer than 40% thought that influenza would cause mortality among older adults. Participants recognized that vaccination can prevent severe influenza among people age 65 or above, but almost 50% did not realize their own increased susceptibility to get influenza if they did not vaccinate. Even fewer agreed with the effect of vaccination on reducing their influenza-related mortality risk. On the other hand, a majority perceived influenza vaccination as beneficial and safe. However, they did not realize the additional advantage of influenza vaccination in reducing their own risks of getting a more severe manifestation of influenza. Almost 70% also denied its positive effects on quality of life and mortality. Unlike previous literature, which identified the time-related or geographically related barriers for vaccination (Lau et al., 2006, 2009), comparatively more participants identified postvaccination sickness and injection-related pain as major hindering factors.
Predicting Influenza Vaccination Intent Of the sample, only 36.4% (n = 111) indicated that they intended to receive vaccination in the following 12 months. Table 3 shows bivariate relationships between patient characteristics and influenza vaccination intent. Eight variables were related to vaccination intent at p < .2. Female gender,
TABLE 2. Beliefs About Influenza and Influenza Vaccination Response Option Item Perceived severity of flu Interference: daily activities Worsens: underlying medical conditions Can be a bad disease Worsens: other health problems Causes death in the elderly Perceived susceptibility With no shot, elderly get more severe flu With no shot, I am likely to get the flu With no shot, my life span shortened I get sick easily Perceived benefit Good for elderly to get flu shot Flu shot benefits society Flu shot prevents flu in elderly Flu shot is safe Flu shot protects me from more severe flu Flu shot improves my quality of life Getting a flu shot lengthens my life span Perceived barriers Hard to access I have gotten sick from a flu shot Shots are painful No time
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SD
D
A
SA
M
SD
5.3 1.3 5.9 3.6 4.9
20.8 30.7 32.4 38.6 56.2
50.9 41.5 32.7 39.5 17.6
23.1 26.5 29.1 18.3 21.2
2.96 2.93 2.85 2.73 2.55
0.81 0.79 0.91 0.80 0.88
1.0 3.9 2.6 38.9
36.6 44.8 58.4 37.6
41.8 36.3 21.6 18.3
20.6 15.0 17.0 5.2
2.82 2.62 2.53 1.90
0.76 0.79 0.80 0.88
1.6 1.6 1.0 3.3 1.6 6.2 10.1
4.6 8.2 26.5 25.2 34.3 64.7 65.4
50.3 45.8 45.4 47.1 42.5 22.2 17.6
43.5 44.4 27.1 24.5 21.6 6.9 6.9
3.36 3.33 2.99 2.93 2.84 2.30 2.21
0.65 0.70 0.76 0.79 0.78 0.69 0.71
2.6 31.0 39.5 68.0
3.9 47.4 45.1 24.8
36.3 18.0 11.4 5.6
57.2 3.6 3.9 1.6
3.48 1.94 1.80 1.41
0.70 0.80 0.79 0.67
Note. N = 306. Cell entries are percent selecting each response option. SD = strongly disagree; D = somewhat disagree; A = somewhat agree; SA = strongly agree.
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TABLE 3. Characteristics of Participants With and Without Intention to Receive Influenza Vaccination Vaccination Intention Yes (n = 111) Characteristic Age Health beliefs Perceived severity Perceived susceptibility Perceived benefit Perceived barrier
Gender (male) With spouse (yes) Living arrangement Living alone With spouse With family Financial strain (yes) Comorbiditiesa Perceives self as unhealthy (yes) Advice: influenza vaccination From family (yes) From mass media (yes) From healthcare professionals (yes) Had current influenza vaccination (yes) Past postvaccination discomfort (yes)
No (n = 195)
M
SD
M
SD
p
74.2
5.5
73.9
7.0
.27
15.14 11.34 21.82
3.01 2.37 3.05
13.39 9.04 18.89
2.82 1.91 2.83
6.05
1.94
7.02
1.68
.01 .01 .01 .01
n
%
n
%
61 86
55.0 77.5
129 158
66.2 81.0
.05
16 40 55 13 44 87
14.4 36.0 49.5 11.7 39.6 78.4
29 72 94 26 41 150
13.8 36.9 48.2 13.3 21.0 76.9
.27
20 68 67 97 1
18.0 61.3 60.4 87.4 1.0
34 119 129 82 7
17.4 61.0 66.2 42.1 7.0
.43 .46 .31 .001 .03
.43 .001 .44
Note. N = 306. aThree or more chronic disease comorbidities.
presence of multimorbidity, greater perceived susceptibility to influenza, greater perceived disease severity, and greater perceived benefit were positively associated with a greater intention to obtain further vaccination. Perceived barriers, on the other hand, had negative effects on intention. Current vaccination status was also positively associated with the intention for further vaccination. About 54.2% of the currently vaccinated participants intended to get vaccinated next year, whereas 89% of the unvaccinated participants did not intend to obtain a vaccination next year (p < .001). All except one participant (n = 8) who experienced postvaccination discomfort did not intend to have future vaccination. All eight variables were entered into the logistic regression model, which significantly predicted the intention for future vaccination (omnibus test of model coefficients, p< .001). Results are summarized in Table 4. After controlling for the confounding effects of gender and multiple comorbidities, higher perceived susceptibility (OR = 1.42, 95% CI [1.14, 1.78]) independently predicted intention of future vaccination, whereas the experience of postvaccination discomfort was negatively associated with intention to be vaccinated (OR = 0.63, 95% CI [0.006, 0.633]).
DISCUSSION This is the first study to examine the influenza vaccination intent among Chinese older people who are at risk for influenza
and its serious complications. Although an intention for action has been regarded as a strongest predictor of behavior (Ajzen & Fishbein, 1980), only 36.3% of this group of at-risk Chinese older adults intended to receive influenza vaccinations in the following 12 months. Indeed, the results also identified the suboptimal current influenza vaccination status among this high-risk group by referencing to WHO recommendations (i.e., 75% vaccination rate among the at-risk population; WHO, 2012). Indeed, the vaccination rate was even lower than that in the general older population residing in the same city (i.e., 64%; Kwong et al., 2009). The findings conform to the reported disparities in the medical risk status and the influenza vaccination TABLE 4. Predictors of Intention for Future Vaccination Predictor Control variable Gender Multimorbidity Predictive variable Perceived severity Perceived susceptibility Perceived benefit Perceived barrier Current vaccination Postvaccination discomfort
B
SE
p
OR [95% CI]
0.59 0.82
.35 .37
.09 .03
1.80 [.92, 3.55] 2.27 [1.11, .66]
0.09 0.35 −0.03 −0.16 0.69 −2.76
.07 .11 .09 .11 .53 1.17
.21 1.09 [.95, 1.24] .002 1.42 [1.14, 1.78] .73 0.97 [.81, 1.16] .13 0.85 [.69, 1.05] .20 1.99 [.70, 5.61] .02 0.063 [.006, .63]
Note. N = 306.
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Influenza Vaccination Intent
Nursing Research • July/August 2014 • Volume 63 • No. 4
rate for the Western population (Nichol et al., 2004; Landi et al., 2005; Li, 2010). In fact, participants in this study were in regular contact with healthcare professionals to manage their chronic medical illnesses. Such a suboptimal influenza vaccination status and intent deserves prompt attention from healthcare services in protecting this at-risk group against influenza and its serious complications. Health beliefs and past vaccination experiences had significant roles in determining the influenza vaccination intent among the at-risk Chinese older adults in our sample. For health beliefs, not realizing their own increased susceptibility to influenza, resulting from the synergistic effects of old age and medical risk factors, was highly prominent in reducing their vaccination intent. Such low vaccination intention was also related to their inadequate awareness of the additional benefits of influenza vaccination, which prevent them from getting severe flu and developing serious complications, including mortality. Such health belief, indeed, has been identified in international studies as prominently affecting the influenza vaccination behaviors among the general older population (Chi & Neuzil, 2004; Kwong et al., 2009; Lau et al., 2006; Tabbarah et al., 2005; Zimmerman et al., 2003). This study extends the existing knowledge and indicates the additional role of such health beliefs in affecting the vaccination intent. Conforming to the TRA and previous findings, this study suggests the significant impact of past experience in influencing the influenza vaccination intent of at-risk Chinese older adults (Armstrong et al., 2001; Nagata et al., 2013). The findings indicate that almost 90% of unvaccinated at-risk Chinese older adults had no intention for influenza vaccination in the forthcoming year. Encouraging influenza vaccination among this at-risk group may then result in a “carryover” effect to encourage vaccination in the subsequent year. However, older adults’ experiences in previous vaccination also play an important role in affecting this carryover effect. In particular, these findings suggest that postvaccination discomfort discouraged vaccination intent. Although the incidence of the postvaccination discomfort was very low among this at-risk group (i.e., 3.9%), some reported complaints (e.g., cough, transient loss of voice) might just occur coincidently with the vaccination, and its impact on the vaccination intent should not be taken for granted. Then again, the study did not identify the influence of health messages from different sources on influenza vaccination intent. The influence of subjective norm on intention might be less prominent in the context of influenza vaccination. An alternative explanation might also be related to the fact that such health messages were mainly delivered during the peak seasons for influenza and emphasized more on urging older adults to receive a current influenza vaccination. The suboptimal influenza vaccination status and the low intention for subsequent vaccination imply a prompt need to promote this crucial preventive care among the at-risk Chinese
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older adults. The need for this high-risk group to attend regular medical follow-up provides a good contact point to promote influenza vaccination. Their low intention implies the importance of setting up a surveillance and client reminder system in the GOPC to monitor the vaccination status of this high-risk group year by year (Ndiaye et al., 2005). The system can generate an automated message when older adults are due for influenza vaccination. Healthcare professionals would remind them to get vaccinated during medical follow-up accordingly. They can clarify any concerns about the vaccination- induced influenza or postvaccination discomfort. Monitoring the older adults’ postvaccination status, such as subsequent influenza, postvaccination discomfort, influenza-related complications, and hospitalization, and entering such information into the surveillance and client reminder system can help to generate important statistics to reflect the positive impact of vaccination. Such local statistics would be of great value for public education. Educative, supportive intervention would be one approach to cultivating a positive health belief toward influenza and its vaccination (Ndiaye et al., 2005). Efforts must be made to educate this high-risk group about the especially deleterious impact of influenza on complicating their medical conditions and the additional benefit of annual vaccination in delimiting the infection and preventing serious complications. To address the workforce constraints in healthcare, broadcasting videobased education in waiting halls could be a cost-effective alternative. Modeling technique by sharing the peers’ positive vaccination experience and presenting a vivid scenario to illustrate the ways to cope with the common barriers (such as fear of pain and postvaccination discomfort) have been suggested as effective to shape health behavioral changes (Krouse, 2001).
Limitations Several methodological issues are worth considering. The use of a cross-sectional study design precludes concluding that predictors cause influenza vaccination intent. Also, influenza vaccination intent was assessed by self-report. The data may have been subjected to social desirability bias when participants reported such information to a research nurse. Finally, influenza vaccination uptake is a complex phenomenon. Using a quantitative research methodology in this study limited the exploration to a set of predetermined factors. Future studies using a qualitative approach are recommended, which would allow identification of novel predictive factors.
Conclusions This study provides important insights into the factors that affect influenza vaccination intent among Chinese older adults at risk of serious influenza-related complications. The study findings reinforce the role of healthcare professionals in encouraging vaccination uptake among this vulnerable group and draw attention to the impact of health beliefs toward influenza and its vaccination.
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Influenza Vaccination Intent
Accepted for publication December 26, 2013. The authors have no conflicts of interest to report. Corresponding author: Doris S. F. Yu, PhD, RN, Room 729, Esther Lee Building, The Nethersole School of Nursing, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR (e-mail: [email protected]).
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