Abstract
Background
Vaccination data for Asian Americans are comparable to those for whites, possibly because they are reported in aggregate rather than for subgroups. We compared influenza and pneumococcal vaccination rates among eligible Asian Americans and white Americans, and for Vietnamese Americans as a subgroup, and assessed factors associated with these vaccinations.
Methods
Cross-sectional study of data collected from three ethnic groups over 4 years by telephone survey. Data were weighted for selection probability and population estimates and analyzed by multivariate logistic regression.
Results
Vietnamese Americans had a higher rate of influenza vaccination (61%) than Asian Americans (45%) and white Americans (52%), and lower rate of pneumococcal vaccination (41%) than Asian Americans (56%), both lower than white Americans (67%).
Conclusion
When analyzed as a subgroup, Vietnamese Americans had a higher influenza vaccination rate, but a lower pneumococcal vaccination rate, compared to Asian Americans and white Americans, which may indicate that health behaviors and outcomes can differ widely among Asian subgroups. Analyses of preventive care measures in Asian Americans should focus on subgroups to ensure accuracy and quality of assessments.
Keywords: Vietnamese Americans, Adult immunizations, Racial/Ethnic disparities
Introduction
Influenza and pneumococcal vaccinations reduce morbidity and mortality as well as health care costs [1–5]. The Healthy People 2010 goals for these two types of vaccinations are ≥90% coverage in the elderly and ≥60% coverage for younger, at-risk populations, such as those with diabetes mellitus, lung disease, or heart disease. Data from the National Health Interview Survey (NHIS) show that influenza and pneumococcal vaccination rates are lower among older African Americans aged ≥65 years (48 and 33%, respectively) and older Latinos (54 and 32%, respectively) than among older non-Hispanic whites (66 and 57%, respectively) [6]. Rates for influenza and pneumococcal vaccination among Asian Americans are not usually reported because of the low numbers of respondents in such surveys, but these rates are generally thought to be comparable to those of whites [7, 8]. To date, however, most reported national health data on rates among Asian Americans have been in the aggregate, seldom including specific subpopulations, even though the Asian American population is made up of diverse groups of ethnic subpopulations with varied health behaviors and outcomes [9, 10].
Vietnamese Americans, the fourth-largest Asian population in the United States, are less likely than general population to receive some preventive health services, such as serologic testing and vaccinations for hepatitis B, information and testing for HIV/AIDS, screening for colorectal, breast, and cervical cancers [11–18]. Interventions and education have been successful in increasing rates of Papanicolaou testing for cervical screening and vaccination for hepatitis B, decreasing high rates of cigarette smoking, and improving rates for monitoring blood pressure and for organ donation/transplantation in the Vietnamese community [19–25].
The U.S. Centers for Disease Control and Prevention (CDC) currently recommends influenza vaccination for people at high risk for influenza-related complications and severe disease, such as people aged ≥50 years, people of any age with certain chronic medical conditions; and household contacts who have frequent interaction and who can transmit influenza to people at high risk, and health-care workers [26]. The Advisory Committee on Immunization Practices (ACIP) recommends that pneumococcal polysaccharide vaccine be administered to people aged ≥65 years; immunocompetent people aged ≥2 years who are at increased risk for illness and death from pneumococcal disease because of certain chronic medical conditions; people with functional or anatomic asplenia; and immunocompromised people who are at high risk for infection [27]. People aged ≥65 years should be administered a second dose of pneumococcal vaccine if they received the first dose of vaccine ≥5 years previously and were aged <65 years at that time [27].
The objectives of the present study were to compare the rates of influenza and pneumococcal vaccination in Vietnamese Americans in Santa Clara County, California, which has the third-largest Vietnamese American population for any county/city in the United States, with rates for Asian Americans and white Americans in California, and to assess factors associated with receipt of these vaccinations in these older adults.
Methods
Overview and Data Sources
We obtained approval for this study from the institutional review boards of the University of California, San Francisco (UCSF) and the CDC. For Vietnamese Americans, self-reported influenza and pneumococcal vaccination status was obtained from the Racial and Ethnic Approaches to Community Health (REACH) 2010 Risk Factor Survey conducted annually in Santa Clara County, California, from 2002 to 2005 [28]. Vietnamese Americans aged ≥18 years were sampled by random-digit dialing from area telephone listings of the 35 most common Vietnamese last names, which are estimated to cover 99% of the target population. The REACH survey was administered in Vietnamese or English, with a mean cooperation rate of 62% for households screening and 64% for family members interviewed over the 4-year period.
For non-Hispanic whites and Asians, vaccination status (based on self-reports) was obtained from the California Behavioral Risk Factor Surveillance System (BRFSS) conducted over the same 4 years. The BRFSS is an ongoing, state-based, random-digit-dialing telephone survey of the non-institutionalized U.S. civilian population aged ≥18 years. Data from the California BRFSS were used to create vaccination estimates for Asian Americans in the aggregate and for non-Hispanic whites. The BRFSS was administered in English and Spanish; the mean response rate was 53% for households screening and 60% for family members interviewed over the 4-year period.
Outcomes of Interest
The survey questions related to this report were similar on the two telephone surveys. In the REACH questionnaire, participants were asked: “During the past 12 months, have you had a flu shot?” and “Have you ever had a pneumonia vaccination?” In the BRFSS survey, participants were asked: “During what month and year did you receive your most recent flu vaccination?” and “Have you ever had a pneumonia shot? A pneumonia shot or pneumococcal vaccine is usually given only once or twice in a person’s lifetime and is different from the flu shot.” Analysis of the rates for influenza vaccination was restricted to persons who were aged ≥50 years, and analysis of the rates of pneumococcal vaccination was restricted to persons aged ≥65 years. These eligibility criteria are based on well-established clinical indications for these vaccinations and are in accordance with CDC guidelines.
Covariates
The covariates included in the multivariate models were age, sex, education (less than high school, high school, or at least some college), household income per year (<$25,000, $25–50,000, ≥$50,000, or unknown), smoking status (current, former, or never), diagnosed as having diabetes mellitus (yes or no), diagnosed as having heart disease (yes or no), and had a checkup within the last year (yes or no). Because the question of whether the participant had a checkup within the last year was asked in the BRFSS survey only in years 2002 and 2005, analyses of the BRFSS data that included that variable were limited to those two years.
Analytic Strategies
Bivariate analyses using the chi-square test were performed for categorical measures and using analysis of variance for continuous variables to explore any differences in socio-demographic and healthcare factors and vaccination receipt between the non-Hispanic white, Asian American, and Vietnamese American populations. Multivariate logistic regression analyses were then used to examine factors associated with receipt of vaccination among Vietnamese Americans and to examine racial differences in receiving vaccination using Vietnamese Americans as the reference group. Adjusted odds ratios with 95% confidence intervals are presented. SAS/STAT software, Version 9.1.2 (SAS Institute Inc., Cary, NC), was used in the analyses to account for the complex sampling design for both the REACH 2010 and BRFSS data.
Results
In all, 44.9% of the participants in the REACH survey and 35% of those in the BRFSS met the age and race/ethnic criteria and were included in the analysis. The mean age (in years) of non-Hispanic whites was 65; Asian Americans, 61; and Vietnamese Americans, 62 (Table 1). Of eligible whites, 46% were male, versus 48% of Asian Americans and 49% of Vietnamese Americans. Based on the self-reported data, 54% of whites had a history of cigarette smoking, versus 28% of Asian Americans and 27% of Vietnamese Americans. Ninety-five percent of whites had at least a high school education, versus 98% of Asian Americans and 59% of Vietnamese Americans. Twenty percent of whites had an annual income less than $25,000, compared with 25% of Asian Americans and 59% of Vietnamese Americans. Seventy-four percent of whites had a checkup within the past year, versus 74% of Asian Americans and 84% of Vietnamese Americans. Ten percent and 2% of whites, respectively, had been diagnosed with diabetes or heart disease, versus 16 and 1% of Asian Americans and 11 and 7% of Vietnamese Americans. Vietnamese Americans had a higher rate of influenza vaccination (61%) than Asian Americans (45%) and whites (52%) but a lower rate of pneumococcal vaccination (41%) than either Asian Americans (56%) or whites (67%). Thus, Vietnamese Americans had the highest rate of influenza vaccination and whites, the highest rate of pneumococcal vaccination.
Table 1.
Sociodemographic characteristics, influenza (Age ≥50 years) and Pneumococcal vaccinations (Age ≥65 years) among non-Hispanic White, Asian, and Vietnamese American, 2002–2005
| Variable | White N = 6,508 |
Asian N = 259 |
Vietnamese N = 1,922 |
|---|---|---|---|
| Age, years (mean)* | 64.7 (64.4, 65.0) | 61.2 (59.7, 62.8) | 62.1 (61.7, 62.6) |
| Male sex (%)‡ | 45.5 (45.2, 45.7) | 48.4 (41.0, 55.9) | 49.3 (47.2, 51.5) |
| Smoker (%)* | |||
| Current | 11.2 (10.3, 12.1) | 8.4 (4.3, 12.5) | 12.2 (10.6, 13.8) |
| Former | 42.5 (41.1,43.9) | 19.9 (14.1, 25.7) | 15.0 (13.3, 16.7) |
| Never | 46.3 (44.9, 47.7) | 71.7 (65.0, 78.3) | 72.7 (70.6, 74.8) |
| Education (%)* | |||
| Some college | 73.2 (74.5, 72.0) | 84.0 (78.4, 89.6) | 31.4 (29.1, 33.8) |
| High school | 21.6 (20.4, 22.8) | 14.6 (9.1, 20.0) | 27.3 (25.1, 29.4) |
| Less than high school | 5.1 (4.5, 5.7) | 1.5 (0.01, 2.9) | 41.3 (38.8, 43.7) |
| Income (%)* | |||
| < $25K | 20.1 (19.0, 21.2) | 24.7 (18.2, 31.2) | 59.0 (56.4, 61.5) |
| $25K–$50K | 22.9 (21.7, 24.0) | 19.1 (13.2, 24.9) | 15.7 (13.8, 17.5) |
| > $50K | 46.7 (45.3, 48.1) | 47.8 (40.4, 55.2) | 9.6 (8.1, 11.1) |
| Unknown | 10.3 (9.4, 11.1) | 8.4 (4.5, 12.3) | 15.7 (14.0, 17.5) |
| Last check-up† | 73.7 (71.5, 75.8) | 73.9 (62.6, 85.3) | 84.4 (82.7, 86.2) |
| Diagnosed with diabetes mellitus (%) | 10.7 (9.8, 11.5) | 16.1 (10.4, 21.9) | 11.4 (9.9, 13.0) |
| Has heart disease (%)* | 2.1 (1.7, 2.4) | 1.2 (0.0, 2.9) | 7.4 (6.0, 8.7) |
| Had influenza vaccination (%)* | 51.7 (50.3, 53.1) | 45.3 (37.9, 52.7) | 60.6 (58.2, 63.1) |
| Had pneumococcal vaccination (%)* | 67.0 (65.1, 68.9)* | 56.0 (41.6, 70.5) | 41.0 (37.2, 44.7) |
P < 0.0001 value comparing ethnic groups
P < 0.05
Check-up within past year was measured only in the 2002 and 2005 BRFSS surveys
Values in parenthesis are lower and upper limit of 95% confidence interval
In bivariate analyses (Table 2), older age, lower education, and income, having a checkup in the past year, and having been diagnosed with diabetes and heart disease were positively associated with influenza vaccination in whites and Vietnamese Americans, while current smoking was negatively associated with vaccination in whites and Vietnamese Americans. Among whites, women had a higher influenza vaccination rate than men. In whites, female sex and having a recent checkup in the past year were associated with pneumococcal vaccination.
Table 2.
Prevalence of influenza (Age ≥50 years) and Pneumococcal (Age ≥65 years) vaccination by sociodemographic variables among non-Hispanic White, Asian, and Vietnamese American adults, 2002–2005
| Variable | Had Influenza Vaccination (%)
|
Had Pneumococcal Vaccination (%)
|
||||
|---|---|---|---|---|---|---|
| White N = 6,508% (95% CI) |
Asian N = 259% (95% CI) |
Vietnamese N = 1,922% (95% CI) |
White N = 3,132% (95% CI) |
Asian N = 76% (95% CI) |
Vietnamese N = 630% (95% CI) |
|
| Age, years | ||||||
| < 65 | 34.4 (32.5, 36.2)* | 29.9 (22.1, 37.8)* | 48.4 (45.4, 51.4)* | – | – | – |
| ≥65 | 72.5 (70.7, 74.2) | 75.0 (62.9, 87.1) | 82.0 (78.6, 85.4) | 67.0 (65.1,68.9) | 56.0 (41.6, 70.5) | 43.5 (39.2, 47.7) |
| Sex (%) | ||||||
| Male | 48.8 (46.6, 51.0)* | 40.7 (29.3, 52.0) | 60.1 (56.6, 63.6) | 60.8 (57.7, 64.0)* | 41.3 (20.8, 61.8) | 43.6 (38.0, 49.3) |
| Female | 54.2 (52.5, 56.0) | 49.6 (40.0, 59.3) | 61.1 (57.9, 64.3) | 71.4 (69.2, 73.7) | 67.3 (49.2, 85.5) | 43.3 (37.1, 49.5) |
| Smoker (%) | ||||||
| Current | 37.2 (33.1, 41.4)* | 36.9 (11.4, 62.5) | 50.4 (43.3, 57.4)† | 64.4 (57.3, 71.5) | 51.8 (0.0, 100.0) | 45.0 (30.2, 59.9) |
| Former | 56.5 (54.4, 58.6) | 47.0 (30.8, 63.3) | 64.7 (58.7, 70.6) | 69.4 (66.7, 72.0) | 55.8 (28.6, 82.9) | 46.7 (37.3, 56.2) |
| Never | 50.8 (48.8, 52.9) | 45.8 (36.8, 54.7) | 61.6 (58.7, 64.5) | 64.9 (62.0, 67.7) | 56.3 (39.2, 73.4) | 42.6 (37.6, 47.6) |
| Education (%) | ||||||
| Some college | 51.3 (49.7, 52.9)‡ | 43.9 (35.7, 52.2) | 52.4 (48.0, 56.9)* | 67.0 (64.7, 69.3) | 57.5 (41.6, 73.4) | 48.2 (38.8, 57.6) |
| High school | 51.2 (48.2, 54.3) | 55.0 (35.6, 74.5) | 57.1 (52.5, 61.7) | 66.8 (62.9, 70.6) | 50.5 (20.4, 80.5) | 47.9 (39.2, 56.6) |
| Less than high school | 59.6 (53.5, 65.8) | 13.9 (0.0, 41.3) | 69.3 (65.8, 72.8) | 67.7 (60.6, 74.8) | 100.0 (−) | 40.1 (34.4, 45.8) |
| Income (%) | ||||||
| < $25K | 56.4 (53.5, 59.4)* | 56.9 (42.0, 71.8) | 66.2 (63.1, 69.3)* | 67.1 (63.6, 70.6)‡ | 42.2 (20.3, 64.2) | 45.3 (40.2,50.4)‡ |
| $25K–$50K | 54.1 (51.3, 57.0) | 38.4 (21.7, 55.1) | 48.6 (42.5, 54.7) | 70.1 (66.6, 73.5) | 50.1 (18.5, 81.8) | 52.8 (35.7, 70.0) |
| > $50K | 47.0 (45.0, 49.1) | 40.8 (30.1, 51.6) | 44.7 (36.7, 52.8) | 62.6 (59.0, 66.2) | 78.3 (58.6, 98.1) | 51.5 (27.0, 76.1) |
| Unknown | 58.6 (54.2, 62.9) | 52.3 (28.6, 76.0) | 61.4 (55.4, 67.3) | 70.1 (65.2, 75.1) | 65.9 (28.4, 100.0) | 32.4 (23.8, 41.1) |
| Last check-up (%)a | ||||||
| Within past year | 48.7 (45.8, 51.6)* | 31.3 (17.5, 45.1) | 65.3 (62.8, 67.9)* | 66.7 (63.2, 70.3)* | 47.1 (15.9, 78.3) | 44.0 (39.5, 48.5) |
| No | 30.7 (26.2, 35.1) | 33.2 (8.5, 57.9) | 35.6 (29.6, 41.6) | 53.8 (45.4, 62.2) | 72.2 (28.1, 100.0) | 37.1 (23.2, 51.1) |
| Diagnosed with diabetes mellitus (%) | ||||||
| Yes | 67.6 (63.6, 71.6)* | 61.0 (42.3, 79.7) | 76.1 (70.0, 82.1)* | 68.8 (63.6, 73.9) | 49.4 (20.3, 78.4) | 44.1 (33.9, 54.3) |
| No | 49.8 (48.3, 51.3) | 42.3 (34.2, 50.3) | 58.6 (55.9, 61.2) | 66.7 (64.7, 68.8) | 57.8 (42.4, 73.2) | 43.4 (38.7, 48.1) |
| Has heart disease (%) | ||||||
| Yes | 68.3 (60.1, 76.5)* | 50.5 (0.0, 100.0) | 76.7 (68.7, 85.6)† | 74.1 (66.0, 82.2) | 57.0 (42.5, 71.6) | 51.3 (37.6, 65.0) |
| No | 51.4 (50.0, 52.8) | 45.2 (37.8, 52.7) | 59.6 (57.0, 62.2) | 66.8 (64.9, 68.7) | 0.0 (−) | 42.7 (38.2, 47.1) |
P < 0.0001 based on bivariate logistic regression models comparing those who had versus those not having the vaccine
P < 0.01
P < 0.05
Check-up within past year was only measured in 2002 and 2005 for the BRFS survey
CI = confidence interval
In the multivariate logistic regression model including all three racial and ethnic groups and employing Vietnamese Americans as the referent group (Table 3), Vietnamese ethnicity, increasing age, having had a checkup in the past year, and having been diagnosed with diabetes or heart disease were all significantly associated with receipt of the influenza vaccine. Factors significantly associated with having had the pneumococcal vaccination included white race, increasing age, female sex, being a former smoker, having a checkup in the past year, and having been diagnosed with heart disease.
Table 3.
Multivariate logistic regression model examining factors associated with influenza (Age ≥50 years) and Pneumococcal (Age ≥65 years) vaccinations, in 2002–2005 Santa Clara County, CA REACH 2010 and California BRFSS
| Variable | Influenza Vaccination Odds ratio (95% CI) | Pneumococcal Vaccination Odds ratio (95% CI) |
|---|---|---|
| Ethnicity | ||
| Asian American | 0.28 (0.13, 0.56)* | 1.10 (0.31, 3.88) |
| White American | 0.38 (0.31, 0.47)* | 1.54 (1.11, 2.15)* |
| Vietnamese American (reference) | ||
| Age, years | 1.09 (1.07, 1.10)* | 1.04 (1.02, 1.06)* |
| Gender | ||
| Male | 0.89 (0.75, 1.06) | 0.67 (0.52, 0.87)* |
| Female (reference) | ||
| Smoker | ||
| Current | 0.92 (0.71, 1.20) | 1.32 (0.85, 2.05) |
| Former | 1.18 (0.97, 1.44) | 1.45 (1.11, 1.88)* |
| Never (reference) | ||
| Education | ||
| Some college | 0.82 (0.65, 1.04) | 1.34 (0.93, 1.92) |
| High school | 0.81 (0.64, 1.03) | 1.29 (0.91, 1.84) |
| Less than high school (reference) | ||
| Income | ||
| < $25K (reference) | ||
| $25K–$50K | 0.98 (0.78, 1.22) | 1.41 (0.99, 2.00) |
| > $50K | 1.11 (0.87, 1.40) | 0.99 (0.68, 1.42) |
| Unknown | 0.91 (0.71, 1.16) | 0.79 (0.57, 1.10) |
| Check-up within the past year | ||
| Yes | 1.93 (1.58, 2.36)* | 1.48 (1.06, 2.07)† |
| No (reference) | ||
| Diagnosed with diabetes mellitus | ||
| Yes | 1.42 (1.10, 1.83)* | 1.06 (0.77, 1.46) |
| No (reference) | ||
| Has heart disease | ||
| Yes | 1.92 (1.38, 2.67)* | 1.48 (1.03, 2.12)† |
| No (reference) | ||
P < 0.0001
P < 0.05
CI = confidence interval
In a multivariate analysis for Vietnamese Americans (Table 4), increasing age, having had a recent health checkup, and having been diagnosed with diabetes or heart disease were all significantly associated with influenza vaccination; in contrast, level of education had an inverse relationship with influenza vaccination. Only increasing age was associated with having had pneumococcal vaccination.
Table 4.
Multivariate logistic regression model examining factors associated with having influenza (Age ≥50 years) and Pneumococcal (Age ≥65 years) vaccinations, Vietnamese American in Santa Clara County, 2002–2005
| Variable | Influenza Vaccination | Pneumococcal Vaccination |
|---|---|---|
| Odds Ratio (95% Confidence Interval) | ||
| Age, years | 1.09 (1.07, 1.11)* | 1.04 (1.00, 1.04)† |
| Sex | ||
| Male | 0.96 (0.72, 1.29) | 0.67 (0.42, 1.07) |
| Female (referent) | ||
| Smoker | ||
| Current | 0.95 (0.64, 1.29) | 1.17 (0.57, 2.40) |
| Former | 1.14 (0.78, 1.67) | 1.29 (0.77, 2.16) |
| Never (referent) | ||
| Education | ||
| Some college or more | 0.73 (0.54, 0.98)† | 1.53 (0.90, 2.60) |
| High school | 0.79 (0.59, 1.06) | 1.53 (0.96, 2.44) |
| Less than high school (referent) | ||
| Income | ||
| < $25K (referent) | 0.89 (0.65, 1.23) | 1.49 (0.71, 3.12) |
| $25K–$50K | 0.85 (0.57, 1.28) | 1.47 (0.53, 4.04) |
| > $50K | 0.79 (0.58, 1.09) | 0.59 (0.37, 0.95)† |
| Unknown | ||
| Check-up within the past year | ||
| Yes | 2.72 (2.01, 3.67)* | 1.40 (0.72, 2.74) |
| No (referent) | ||
| Diagnosed with diabetes | ||
| Yes | 1.55 (1.05, 2.28)† | 1.02 (0.62, 1.66) |
| No (referent) | ||
| Diagnosed with heart disease | ||
| Yes | 1.69 (1.02, 2.81)† | 1.35 (0.74, 2.48) |
| No (referent) | ||
P ≤ 0.0001
P ≤ 0.05
Discussion
We found that Vietnamese Americans in Santa Clara County, California, had a higher rate of influenza vaccination than California’s Asian Americans as a group or than California’s non-Hispanic whites, but we also found that these Vietnamese Americans had a lower rate of pneumococcal vaccination than Asian Americans or whites. To our knowledge, this is the first report to compare influenza and pneumococcal vaccination rates for Vietnamese Americans, an immigrant population with generally low socioeconomic status (SES), to other racial and ethnic groups. Regardless, the rates reported here for all three population groups do not approach the Healthy People 2010 goal for influenza and pneumonia vaccinations of ≥90% coverage in persons 65 years and older and ≥60% coverage for at-risk populations.
Our finding of higher rates of influenza vaccination (versus those for whites) in a low-SES population may reflect the better medical infrastructure in Santa Clara County, a wealthy, high-technology County south of San Francisco. The counterintuitive fact that lower education was associated with increased vaccination rates for Vietnamese Americans, may also be attributable to superior health services available in Santa Clara County. Furthermore, when the influenza vaccine is made widely available (e.g., through local pharmacies, facility-based flu clinics) as an annual “shot,” it seems to be less of a problem for Vietnamese Americans who have traditionally been receptive to injections [25]. Vietnamese Americans may believe that the influenza shot is effective because of its widespread favorable publicity, and they may be more likely to ask their doctors and pharmacists about the shot and willing to receive it when their doctors or pharmacists offer it. In contrast, the pneumococcal polysaccharide vaccine, which is generally recommended only once for persons age ≥65, or at most twice for those with specific chronic diseases (e.g., diabetes or chronic lung or heart disease), tends to be less well publicized to all racial and ethnic groups and depends more on visits to a physician’s office and thus on access to medical care. Since it is unlikely that Vietnamese Americans would refuse the pneumococcal vaccine, their lack of receipt is most likely because they are not aware of the vaccine and thus do not ask their doctors(most of whom are themselves Vietnamese) about it. In general, it is believed that Vietnamese doctors tend to do less preventive care than most other physicians [16, 25], and thus the pneumococcal vaccine may be underused in the Vietnamese community. The only way to know for certain would be to perform additional studies to assess the relation of physician characteristics (e.g., physician ethnicity) to the offering of pneumococcal vaccines in the Vietnamese American community. Use of mass media and other strategies may help to raise consciousness among Vietnamese Americans of the need for this office-based vaccination. One controlled trial demonstrated successful promotion of hepatitis B vaccinations among Vietnamese American children aged 3–18 years through use of mass media and community mobilization strategies [25].
Our study has several limitations. First, because of the cross-sectional nature of the data, our findings do not suggest causality but instead suggest the need for additional research into the relation between race/ethnicity and receipt of adult vaccinations. Second, although the two surveys we used were similar in methodology and consisted of similar questions on vaccination, the California BRFSS and the local Santa Clara County REACH 2010 surveys were still somewhat different. The BRFSS questions are in English for Asian Americans and non-Hispanic whites, but the REACH questions for Vietnamese Americans were in Vietnamese and English, and almost all respondents chose Vietnamese (99%). Third, the REACH 2010 survey sampled from a list of Vietnamese surnames while BRFSS was based on random-digit-dialing. In addition, the reliability in such surveys of self-reported vaccination rates is largely unknown in community-based populations. The comparison between Vietnamese Americans in Santa Clara County on the REACH survey and the Asian and non-Hispanic white American population in California at large on the BRFSS survey may not take into account regional variations in receipt of vaccines across the state. Data in non-Hispanic white and other Asian groups were not available for Santa Clara County. Finally, there is often confusion in the general public between influenza and pneumococcal vaccinations. In one focus study on adult vaccinations, participants reported that they lacked information about the benefits or potential side effects of influenza and pneumococcal vaccinations and that their physicians were not routinely informing them of, or recommending, these vaccinations [29].
The strengths of the present study include the large samples for different racial, ethnic, and socioeconomic groups as well as the random nature of the selection of study participants from the general community. Our study also highlights with importance of racial/ethnic subgroup analysis for Asian Americans because simply reporting aggregated data on Asian Americans in general would obscure the differences in the Vietnamese subgroup.
Our study shows that, although it is prudent to recommend that all persons, regardless of race or ethnicity, be vaccinated against influenza and pneumococcal disease, it is important that we understand the racial/ethnic factors that might cause disparities in vaccination rates in certain racial groups as well as the ethnic subgroups within them. The finding in this study of an influenza vaccination rate among Vietnamese Americans, a predominantly low-SES immigrant community, in Santa Clara County that was higher than that of other populations in the state suggests that communities with efficient public health and medical infrastructures can overcome potential disparities in adult vaccinations. But the less-than-optimal rates for both immunizations in all three populations studied indicates that further work is needed to improve vaccination rates against both influenza and pneumococcal disease—two important, continuing, vaccine-preventable causes of morbidity and mortality.
Acknowledgments
This project was funded by the U.S. Centers for Disease Control and Prevention under Cooperative Agreements U50/CCU917412 and U50/CCU922156. The contents of the article are solely the responsibility of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention. Dr. Daniels is a recipient of the Robert Wood Johnson Minority Medical Faculty Development Award and is supported by grant P30-AG15272 under the Resource Centers for Minority Aging Research program funded by the National Institute on Aging, the National Institute of Nursing Research, the National Center on Minority Health and Health Disparities, National Institutes of Health, and the Department of Defense.
Contributor Information
Nicholas A. Daniels, Email: ndaniels@medicine.ucsf.edu, Department of Medicine, Division of General Internal Medicine, University of California, 1701 Divisadero Street, Suite 500, Box 1731, San Francisco, CA 94115, USA
Ginny Gildengorin, Department of Medicine, Division of General Internal Medicine, University of California, 1701 Divisadero Street, Suite 500, Box 1731, San Francisco, CA 94115, USA.
Tung T. Nguyen, Department of Medicine, Division of General Internal Medicine, University of California, 1701 Divisadero Street, Suite 500, Box 1731, San Francisco, CA 94115, USA
Youlian Liao, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Thien-Nhien Luong, Santa Clara County Public Health Department, San Jose, CA, USA.
Stephen J. McPhee, Department of Medicine, Division of General Internal Medicine, University of California, 1701 Divisadero Street, Suite 500, Box 1731, San Francisco, CA 94115, USA
References
- 1.Sisk JE, Moskowitz AJ, Whang W, et al. Cost-effectiveness of vaccination against pneumococcal bacteremia among elderly people. JAMA. 1997;278:1333–9. [PubMed] [Google Scholar]
- 2.Fine MJ, Smith MA, Carson CA, et al. Efficacy of pneumococcal vaccination in adults. A meta-analysis of randomized controlled trials. Arch Intern Med. 1994;154:2666–77. doi: 10.1001/archinte.1994.00420230051007. [DOI] [PubMed] [Google Scholar]
- 3.Wagner C, Popp W, Posch M, Vlasich C, Rosenberger-Spitzy A. Impact of pneumococcal vaccination on morbidity and mortality of geriatric patients: a case-controlled study. Gerontology. 2003;49:246–50. doi: 10.1159/000070405. [DOI] [PubMed] [Google Scholar]
- 4.Watson L, Wilson BJ, Waugh N. Pneumococcal polysaccharide vaccine: a systematic review of clinical effectiveness in adults. Vaccine. 2002;20:2166–73. doi: 10.1016/s0264-410x(02)00112-3. [DOI] [PubMed] [Google Scholar]
- 5.Maciosek MV, Solberg LI, Coffield AB, Edwards NM, Goodman MJ. Influenza vaccination health impact and cost effectiveness among adults aged 50 to 64 and 65 and older. Am J Prev Med. 2006;31:72–9. doi: 10.1016/j.amepre.2006.03.008. [DOI] [PubMed] [Google Scholar]
- 6.Centers for Disease Control and Prevention (CDC) Racial/ethnic disparities in influenza and pneumococcal vaccination levels among persons aged>or = 65 years—United States, 1989–2001. MMWR Morb Mortal Wkly Rep. 2003;52:958–62. [PubMed] [Google Scholar]
- 7.Marin MG, Johanson WG, Jr, Salas-Lopez D. Influenza vaccination among minority populations in the United States. Prev Med. 2002;34:235–41. doi: 10.1006/pmed.2001.0983. [DOI] [PubMed] [Google Scholar]
- 8.Wortley P. Who’s getting shots and who’s not: racial/ethnic disparities in immunization coverage. Ethn Dis. 2005;15(2 Suppl 3):S3-4–6. [PubMed] [Google Scholar]
- 9.Yu SM, Alexander GR, Schwalberg R, Kogan MD. Prenatal care use among selected Asian American groups. Am J Public Health. 2001;91:1865–8. doi: 10.2105/ajph.91.11.1865. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Lee-Lin F, Menon U. Breast and cervical cancer screening practices and inventions among Chinese, Japanese, and Vietnamese Americans. Oncol Nurs Forum. 2005;32:995–1003. doi: 10.1188/05.onf.995-1003. [DOI] [PubMed] [Google Scholar]
- 11.Jenkins CN, McPhee SJ, Wong C, Nguyen T, Euler GL. Hepatitis B immunization coverage among Vietnamese-American children 3 to 18 years old. Pediatrics. 2000;106(6):E78. doi: 10.1542/peds.106.6.e78. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Gellert GA, Maxwell RM, Higgins KV, Mai KK, Lowery R, Doll L. HIV/AIDS knowledge and high risk sexual practices among southern California Vietnamese. Genitourin Med. 1995;71:216–23. doi: 10.1136/sti.71.4.216. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.McPhee SJ, Nguyen TT. Cancer, cancer risk factors, and community-based cancer control trials in Vietnamese Americans. Asian Am Pac Isl J Health. 2000;8:18–31. [PMC free article] [PubMed] [Google Scholar]
- 14.Taylor VM, Schwartz SM, Yasui Y, Burke N, Shu J, Lam DH, et al. Pap testing among Vietnamese women: health care system and physician factors. J Community Health. 2004;29:437–50. doi: 10.1007/s11123-004-3393-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Chen QS, Jr, Ngo-Metzger Q, Tran LQ, Sugrue Mc-Elearney E, Levy ER, Williams G, et al. Hepatitis B vaccination among Vietnamese-American children in a Boston community clinic. Asian Am Pac Isl J Health. 2001;9:179–87. [PubMed] [Google Scholar]
- 16.Nguyen TT, McPhee SJ, Nguyen T, Lam T, Mock J. Predictors of cervical Pap smear screening awareness, intention, and receipt among Vietnamese-American women. Am J Prev Med. 2002;23:207–14. doi: 10.1016/s0749-3797(02)00499-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.McPhee SJ, Nguyen TT. Cancer, cancer risk factors, and community-based cancer control trials in Vietnamese Americans. Asian Am Pac Isl J Health. 2000;8:18–31. [PMC free article] [PubMed] [Google Scholar]
- 18.Walsh JM, Kaplan CP, Nguyen B, Gildengorin G, McPhee SJ, Perez-Stable EJ. Barriers to colorectal cancer screening in Latino and Vietnamese Americans compared with non-Latino white Americans. J Gen Intern Med. 2004;19:156–66. doi: 10.1111/j.1525-1497.2004.30263.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Duong DN, Ryan R, Vo DT, Tran TT. A descriptive study of hypertension in Vietnamese Americans. J Community Health Nurs. 2001;18:1–11. doi: 10.1207/S15327655JCHN1801_01. [DOI] [PubMed] [Google Scholar]
- 20.Choe JH, Taylor VM, Yasui Y, et al. Health care access and sociodemographic factors associated with hepatitis B testing in Vietnamese American men. J Immigr Minor Health. 2006;8:193–201. doi: 10.1007/s10903-006-9322-1. [DOI] [PubMed] [Google Scholar]
- 21.Burke NJ, Jackson JC, Thai HC, et al. ‘Honoring tradition, accepting new ways’: development of a hepatitis B control intervention for Vietnamese immigrants. Ethn Health. 2004;9:153–69. doi: 10.1080/1355785042000222860. [DOI] [PubMed] [Google Scholar]
- 22.Pham H, Spigner C. Knowledge and opinions about organ donation and transplantation among Vietnamese Americans in Seattle, Washington: a pilot study. Clin Transplant. 2004;18:707–15. doi: 10.1111/j.1399-0012.2004.00284.x. [DOI] [PubMed] [Google Scholar]
- 23.Nguyen TT, McPhee SJ, Gildengorin G, et al. Papanicolaou testing among Vietnamese Americans: results of a multifaceted intervention. Am J Prev Med. 2006;31:1–9. doi: 10.1016/j.amepre.2006.03.005. [DOI] [PubMed] [Google Scholar]
- 24.Nguyen TT, McPhee SJ, Bui-Tong N, et al. Community-based participatory research increases cervical cancer screening among Vietnamese-Americans. J Health Care Poor Underserved. 2006;17(Suppl 2):31–54. doi: 10.1353/hpu.2006.0091. [DOI] [PubMed] [Google Scholar]
- 25.McPhee SJ, Nguyen T, Euler GL, et al. Successful promotion of hepatitis B vaccinations among Vietnamese-American children ages 3 to 18: results of a controlled trial. Pediatrics. 2003;111:1278–88. doi: 10.1542/peds.111.6.1278. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Smith NM, Bresee JS, Shay DK, Uyeki TM, Cox NJ, et al. Advisory Committee on Immunization Practices. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP) MMWR Recomm Rep. 2006;55(RR-10):1–42. [PubMed] [Google Scholar]
- 27.Centers for the Disease Control and Prevention. Prevention of pneumococcal disease: recommendations of the Advisory Committee on Immunization Practices (ACIP) MMWR Recomm Rep. 1997;46(RR-8):1–24. [PubMed] [Google Scholar]
- 28.Liao Y, Tucker P, Okoro CA, Giles WH, Mokdad AH, Harris VB. REACH 2010 surveillance for health status in minority communities—United States, 2001–2002. MMWR Surveill Summ. 2004;53(SS-6):1–36. [PubMed] [Google Scholar]
- 29.Daniels NA, Juarbe T, Rangel-Lugo M, Moreno-John G, Pérez-Stable EJ. Focus group interviews on racial and ethnic attitudes regarding adult vaccinations. J Natl Med Assoc. 2004;96:1455–61. [PMC free article] [PubMed] [Google Scholar]