Sage Journals: Discover world-class research

Abstract

Background. The incidence of pertussis in the United States has been increasing. Adult vaccination is important to reduce disease burden and prevent transmission to infants at high risk of complications. The tetanus–diphtheria–acellular pertussis (Tdap) vaccine has been available in the United States since 2005 and is indicated as a one-time replacement for the routine tetanus–diphtheria (Td) booster. However, among adults receiving tetanus vaccination, only about half receive Tdap. Purpose. To identify predictors of adult Tdap vaccination among individuals who receive tetanus vaccine. Methods. National Health Interview Survey data from 2008 were analyzed in 2011. Respondents were 18 to 64 years old, received tetanus vaccination during 2005-2008, and were aware if it contained pertussis. Predictors of Tdap vaccination were identified with multivariate logistic regression using procedures for complex survey methods. Results. Overall, 51.1% of respondents received Tdap. Vaccination was less likely for those 50 to 64 years old compared with those 18 to 24 years old (odds ratio [OR] = 0.61, 95% confidence interval [CI] = 0.38-0.96). Some college education was associated with higher odds of vaccination compared with lower education levels (OR = 1.55, 95% CI = 1.16-2.07). Having 2 to 3 office visits (OR = 2.01, 95% CI = 1.32-3.06) or 4 to 9 office visits (OR = 1.60, 95% CI = 1.06-2.42) in the previous year increased the odds of vaccination compared with no visits. Individuals with functional limitation due to illness had lower odds compared with no limitation (OR = 0.70, 95% CI = 0.54-0.91). Conclusions. In 2008, 51.1% of adult Td vaccinations included pertussis, suggesting continued efforts to remove barriers are needed. Interventions should target older, functionally impaired, and educationally disadvantaged populations.

Keywords

pertussis Tdap adult vaccination prevention National Health Interview Survey

Introduction

The incidence of pertussis in the United States has been rising since 2007, with more than 27 500 cases reported in 2010.¹ Furthermore, the actual number of cases is likely higher, as some are unreported. One contributing factor is that the presentation of pertussis illness in adults is often mild and may be unrecognized, resulting in underreporting and complicating efforts to prevent transmission.² Adult vaccination is important to reduce disease burden and also to protect infants who have not completed the primary vaccination series. In the United States, most pertussis-related deaths occur in infants younger than 3 months.³

In 2006, the Advisory Committee on Immunization Practices recommended the tetanus–diphtheria–acellular pertussis (Tdap) vaccine for adults aged 18 to 64 years as a single replacement dose for the routine tetanus–diphtheria (Td) booster.⁴ More recently, they recommended Tdap for individuals who have close contact with infants younger than 12 months, including those aged 65 years and older.³ Unfortunately, many adults who get the routine Td booster do not receive Tdap. It is a matter of concern that the proportion of tetanus vaccinations that are Tdap has remained essentially unchanged at approximately 50% for several years.^5-7

Most current literature evaluates provider-level factors in relation to Tdap vaccination.^8-10 There is only limited information regarding patient-level factors. In this regard, one study suggests that individuals with a higher education level and those who received a recent influenza vaccination were more likely to report receiving Tdap.¹¹ Given what is currently known about predictors of Tdap, there is a need for more studies that focus on individuals who report receiving Td to determine what additional factors are related to receiving the acellular pertussis formulation. The aim of this study was to describe these factors among adults aged 18 to 64 years in the United States.

Methods

This was a cross-sectional study using data from the 2008 National Health Interview Survey. The survey methodology is described in detail elsewhere.¹² Briefly, the survey is conducted annually to monitor the health of the civilian, noninstitutionalized US population. It uses a multistage sampling plan to identify a representative subset of households covering the 50 states and the District of Columbia. Personal household interviews are conducted by agents of the US Bureau of the Census. Participation in the survey is voluntary.

The current study identified respondents who were aged 18 to 64 years and reported having a tetanus shot since 2005. A total of 1336 subjects had a yes/no response to the survey question, “Did the vaccine include pertussis/whooping cough?” All information related to study variables was obtained from public-use data files made available by the Centers for Disease Control and Prevention. The study was determined to meet oversight exemption criteria by the Institutional Review Board for BayCare Health System and the University of South Florida.

The primary dichotomous outcome variable was Tdap vaccination based on self-report. The potential predictor variables were chosen based on studies suggesting that barriers to vaccination are often related to sociodemographics, utilization of health care services, health status, and an individuals’ preventive behavior.^13-16 Sociodemographic variables included age (18-24, 25-49, and 50-64 years), race-ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, other), gender, language (English, non-English), US census region, dependent children <18 years old (yes/no), marital status (married, not married), education level (high school or less vs more than high school), employment status (employed vs unemployed), and total family income level (<$35 000, $35 000 up to $74 999, $75 000 up to $99 999, and ≥$100 000).

Variables for utilization of health care services included insurance status (private, public, none), office visits within 12 months (0, 1, 2-3, 4-9, ≥10), and presence of any barrier to access (yes/no). Barriers included inability to obtain medical care in the previous 12 months due to cost, waiting too long in the doctor’s office, not able to get through on the telephone, unable to obtain an appointment in a timely manner, office not being open when respondent could attend, or lack of transportation. Physician preventive behavior (yes/no) was defined as a recommendation for Pap smear, mammogram, prostate-specific antigen testing, or colorectal cancer screening.

Health status was assessed by examining coexisting illness, limitations of activity due to illness, and self-reported rating of health. Coexisting medical illnesses (yes/no) included coronary heart disease, angina pectoris, heart attack, heart condition/disease, diabetes, cancer, asthma, emphysema, chronic bronchitis, or weak/failing kidneys in the past 12 months. Psychiatric illness (yes/no) included depression or generalized anxiety. Other health status variables included functional limitation (yes/no) and self-reported health status (very good, good, or not good).

Variables assessing respondent preventive behavior included receiving influenza vaccine (yes/no), ever having pneumococcal vaccine (yes/no), and ever having received hepatitis A, hepatitis B, human papillomavirus, or varicella zoster vaccines (yes/no). Other recommended preventive services included use of sunscreen on a warm sunny day (always or most of the time), ever having a Pap smear, mammogram, prostate-specific antigen test, colorectal screening exam, or ever following advice to change diet, exercise, or reduce alcohol use for high blood pressure (yes/no).

The frequency of Tdap vaccination in relation to predictor variables was described taking into account the complex survey methodology of the National Health Interview Survey. Univariate analysis used logistic regression by class (SAS SURVEYLOGISTIC procedure) to determine the relationship between categorical predictors and the primary outcome. This procedure fits linear logistic regression models for discrete response survey data by the method of maximum likelihood and incorporates the sample design, such as stratification, clustering, and unequal weighting into the analysis. Tests of trend for ordinal variables (age, income, office visits in the past 12 months, education, and self-reported health status) were conducted using logistic modeling without the class statement. Multivariate logistic regression examined adjusted odds ratios (ORs) and 95% confidence intervals (CIs). As an exploratory study, all potential predictor variables were included in the multivariate model. Analyses were conducted using SAS version 9.2. A P value ≤.05 was considered statistically significant.

Results

Sample characteristics and Tdap vaccination rates are shown in Table 1. Of 1336 respondents, 51.1% who received tetanus vaccination reported receiving Tdap. The unadjusted odds of receiving Tdap are shown in Table 2. In univariate analysis, characteristics significantly associated with higher odds of Tdap included female gender (OR = 1.27, 95% CI = 1.02-1.59), Asian and other race-ethnicity (OR = 1.86, 95% CI = 1.14-3.05), college education (OR = 1.67, 95% = CI 1.32-2.12), 2 to 3 office visits in the past year (OR = 1.88, 95% CI = 1.26-2.82), and receiving other vaccines (OR = 1.40, 95% CI = 1.13-1.74). Tests of trend were significant for increasing level of education (P < .001) and increasing level of income (P = .017).

Table 1.

Percentage of Respondents Receiving Tdap by Selected Characteristics: NHIS 2008.

Characteristics	Sample (n)	Pertussis-Containing Vaccine (%)^a
Total	1336	51.1
Age (years)
18-24	171	63.1
25-49	778	51.8
50-64	387	44.5
Gender
Male	572	47.8
Female	764	53.8
Race/ethnicity
White	914	49.6
Black	199	55.7
Hispanic	163	53.2
Other	60	64.6
Language
English	1284	51.4
Other	52	37.7
Geographic region
Northeast	185	49.0
Midwest	339	48.6
South	486	53.9
West	326	50.9
Children <18 years
0	791	51.0
≥1	545	51.2
Marital status
Married	643	48.9
Not married	693	53.2
Education
High school or less	303	41.0
Some college	1031	53.8
Employment status
Not employed	377	49.2
Employed	959	51.8
Income ($)
0-34 999	417	50.1
35 000-74 999	423	46.4
75 000-99 999	178	54.1
≥100 000	265	55.4
Unknown	53	64.7
Insurance status
Private or military^b	1023	50.9
Public^c	122	50.9
No insurance	191	52.3
Office visits last year
None	194	43.4
1	248	49.3
2-3	365	59.1
4-9	334	51.5
≥10	195	45.5
Barrier to access
No	1041	52.5
Yes	295	45.9
Physician behavior
No	566	51.3
Yes	770	51.0
Medical illness
No	911	53.3
Yes	425	46.5
Psychiatric illness
No	807	52.0
Yes	529	49.9
Functional status
Not limited	958	54.9
Limited	378	42.0
Rating of health
Very good	906	54.2
Good	289	45.2
Not good	141	42.9
Influenza
No	831	49.4
Yes	505	54.0
Pneumococcal
No	1143	51.4
Yes	193	49.7
Other vaccination
No	578	46.4
Yes	758	54.8
Patient behaviors
No	272	52.5
Yes	1064	50.7

Abbreviations: Tdap, tetanus–diphtheria–acellular pertussis; NHIS, National Health Interview Survey.

Weighted proportion.

Military coverage includes TRICARE, VA (Veterans Affairs), or CHAMP-VA (Civilian Health and Medical Program of the Department of Veterans Affairs) health plans.

Public health care coverage includes Medicare, Medicaid, Indian Health Service, other government programs, or state-sponsored health plans.

Table 2.

Unadjusted and Adjusted Odds Ratios of Receiving Tdap by Selected Respondent Characteristics: NHIS 2008.

Characteristics	Unadjusted OR (95% CI)	Adjusted OR (95% CI)
Age (years)
18-24	1 (ref)	1 (ref)
25-49	0.63 (0.45-0.88)^a	0.76 (0.52-1.11)
50-64	0.47 (0.33-0.66)^a	0.61 (0.38-0.96)^a
Gender
Male	1 (ref)	1 (ref)
Female	1.27 (1.02-1.59)^a	1.30 (0.95-1.77)
Race/ethnicity
White	1 (ref)	1 (ref)
Black	1.28 (0.92-1.79)	1.18 (0.83-1.67)
Hispanic	1.16 (0.82-1.63)	1.33 (0.83-2.13)
Other	1.86 (1.14-3.05)^a	1.63 (0.94-2.83)
Language
English	1 (ref)	1 (ref)
Other	0.57 (0.33-0.99)^a	0.57 (0.28-1.14)
Geographic region
Northeast	1 (ref)	1 (ref)
Midwest	0.98 (0.65-1.49)	0.98 (0.64-1.49)
South	1.22 (0.83-1.79)	1.28 (0.86-1.92)
West	1.08 (0.73-1.60)	1.02 (0.67-1.53)
Children <18 years
0	1 (ref)	1 (ref)
≥1	1.01 (0.79-1.29)	0.89 (0.65-1.21)
Marital status
Married	1 (ref)	1 (ref)
Not married	1.19 (0.95-1.48)	1.12 (0.87-1.45)
Education
High school or less	1 (ref)	1 (ref)
Some college	1.67 (1.32-2.12)^a	1.55 (1.16-2.07)^a
Employment status
Not employed	1 (ref)	1 (ref)
Employed	1.11 (0.85-1.44)	0.99 (0.74-1.32)
Income ($)
0-34 999	1 (ref)	1 (ref)
35 000-74 999	0.86 (0.67-1.11)	0.87 (0.65-1.18)
75 000-99 999	1.17 (0.83-1.67)	1.16 (0.77-1.73)
≥100 000	1.24 (0.91-1.69)	1.18 (0.78-1.79)
Unknown	1.82 (1.02-3.26)^a	1.69 (0.89-3.20)
Insurance status
Private or military^b	1 (ref)	1 (ref)
Public^c	1.00 (0.67-1.49)	1.41 (0.82-2.44)
No insurance	1.06 (0.71-1.57)	1.46 (0.90-2.38)
Office visits last year
None	1 (ref)	1 (ref)
1	1.27 (0.85-1.89)	1.39 (0.92-2.11)
2-3	1.88 (1.26-2.82)^a	2.01 (1.32-3.06)^a
4-9	1.38 (0.92-2.07)	1.60 (1.06-2.42)^a
≥10	1.09 (0.69-1.70)	1.49 (0.91-2.46)
Barrier to access
No	1 (ref)	1 (ref)
Yes	0.77 (0.60-0.98)^a	0.80 (0.60-1.05)
Physician behavior
No	1 (ref)	1 (ref)
Yes	0.99 (0.79-1.23)	1.04 (0.73-1.46)
Medical illness
No	1 (ref)	1 (ref)
Yes	0.76 (0.60-0.96)^a	0.89 (0.66-1.19)
Psychiatric illness
No	1 (ref)	1 (ref)
Yes	0.92 (0.73-1.15)	1.08 (0.81-1.42)
Functional status
Not limited	1 (ref)	1 (ref)
Limited	0.60 (0.47-0.76)^a	0.70 (0.54-0.91)^a
Rating of health
Very good	1 (ref)	1 (ref)
Good	0.70 (0.53-0.92)^a	0.84 (0.62-1.14)
Not good	0.63 (0.44-0.91)^a	0.84 (0.54-1.30)
Influenza
No	1 (ref)	1 (ref)
Yes	1.20 (0.95-1.52)	1.22 (0.94-1.59)
Pneumococcal
No	1 (ref)	1 (ref)
Yes	0.94 (0.70-1.25)	1.00 (0.71-1.40)
Other vaccination
No	1 (ref)	1 (ref)
Yes	1.40 (1.13-1.74)^a	1.13 (0.90-1.41)
Patient behaviors
No	1 (ref)	1 (ref)
Yes	0.93 (0.71-1.23)	0.81 (0.53-1.22)

Abbreviations: Tdap, tetanus–diphtheria–acellular pertussis; NHIS, National Health Interview Survey; OR, odds ratio; 95% CI, 95% confidence interval; ref, reference.

P < .05.

Military coverage includes TRICARE, VA (Veterans Affairs), or CHAMP-VA (Civilian Health and Medical Program of the Department of Veterans Affairs) health plans.

Public health care coverage includes Medicare, Medicaid, Indian Health Service, other government programs, or state-sponsored health plans.

Characteristics significantly associated with lower odds of Tdap in univariate analysis included age 25 to 49 years (OR = 0.63, 95% CI = 0.45-0.88), age 50 to 64 years (OR = 0.47, 95% CI = 0.33-0.66), non-English language (OR = 0.57, 95% CI = 0.33-0.99), barrier to access (OR = 0.77, 95% CI = 0.60-0.98), medical illness (OR = 0.76, 95% CI = 0.60-0.96), functional limitations (OR = 0.60, 95% CI = 0.47-0.76), good health status (compared with very good; OR = 0.70, 95% CI = 0.53-0.92), and not good rating of health (OR = 0.63, 95% CI = 0.44-0.91). Tests of trend were significant for increasing age (P < .001) and decreasing health status (P < .002).

In multivariate analysis, several characteristics remained significantly associated with Tdap vaccination (Table 2). College education predicted receiving Tdap (OR = 1.55, 95% CI = 1.16-2.07), as did 2 to 3 office visits (OR = 2.01, 95% CI = 1.32-3.06) or 4 to 9 office visits (OR = 1.60, 95% CI = 1.06-2.42) in the past year. Age 50 to 64 years (OR = 0.61, 95% CI = 0.38-0.96) and functional limitations (OR = 0.70, 95% CI = 0.54-0.91) were associated with lower odds of receiving Tdap.

Discussion

In this study, 51.1% of adults aged 18 to 64 years who received tetanus vaccination during 2005-2008 received Tdap. For several reasons, we believe vaccination rates should be higher. First, contraindications are rare and unlikely to contribute to low coverage.¹⁷ Also, coverage has continued to be about 50%, indicating minimum influence of recent introduction.^6,7 Last, this study does not show that pertussis vaccination is less likely for the uninsured, suggesting cost does not play a role. Therefore, other factors must contribute to undervaccination.

As age increased, the odds of Tdap utilization decreased. While young parents are a source of pertussis transmission to infants, grandparents and other adults may also be sources and should be vaccinated.¹⁸ Another predictor is education, which has been shown to be associated with vaccination.^11,19,20 This study builds on previous studies by suggesting that higher education predicts receiving acellular pertussis vaccine in those receiving Td, possibly related to greater awareness of pertussis and its risks.

This study uses patient-level data; the impact of provider-level factors on pertussis vaccination is also important. Provider barriers might include doubt regarding the seriousness of pertussis and lack of knowledge about immunization guidelines.^21,22 These barriers reduce the likelihood of provider recommendation, which influences patients’ decisions regarding vaccination.^11,22,23 Providers may also miss opportunities to vaccinate because of competing demands, which could explain why respondents in this study were not more likely to receive pertussis vaccination with 10 or more yearly office visits.^21,24 In the setting of complex office visits, there may be little time to fully explain the benefit of pertussis vaccination and its rationale over routine tetanus vaccine.

It was interesting to find that participants reporting functional limitation were 30% less likely to be vaccinated. Other studies have shown increased vaccination with chronic illness, which may be related in part to patient perception of susceptibility to disease and potential severity of the outcome.^25-27 In our analysis, perhaps patients with more severe illness and associated limitations have concerns about pertussis vaccination worsening their condition. Misconceptions of this sort are not uncommon and will require further study.

We recognize the limitations of this analysis. Because multivariable models require complete data on included variables, missing data may reduce statistical power by reducing the effective sample size. We recoded variables that would have naturally led to missing data (eg, men responding to questions about mammography) in order to include them in our analysis. Also, the data are subject to respondent recall bias. Tdap vaccination was self-reported and was not verified by medical records. Systematic misclassification is possible, which could affect our conclusions.

Our study sample was selected based on a yes/no response to the question, “Did the doctor tell you the vaccine included the pertussis or whooping cough vaccine?” Individuals with responses of doctor did not say, not ascertained, and don’t know were excluded from analysis (n = 3189). Compared with this excluded group, our sample was more likely to be white, English-speaking, female, and married. They were also more likely to have college education, be employed, have higher income, and have private insurance. Based on these differences, we suspect that our study overestimated pertussis vaccination rates and the actual proportion of persons receiving Tdap is likely less than the 51% found in our study.

In 2008, approximately half of adult Td vaccinations included acellular pertussis, suggesting a need for increased awareness regarding pertussis, its consequences, and methods of prevention. Older individuals, those who are educationally disadvantaged, and those with functional impairment may be especially suited for supplemental immunization initiatives.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Author Biographies

Tracy L. Johns, PharmD, is Associate Program Director at the University of South Florida Family Medicine Residency Program and Director of Research at the Dr Joseph A. Eaddy Family Medicine Research Center in Clearwater, Florida.

Richard Roetzheim, MD, MSPH, is Professor of Family Medicine at the University of South Florida, College of Medicine in Tampa, Florida.

Ren Chen, MD, MPH, is a member of the Biostatistics Core in the Clinical and Translational Science Institute at the University of South Florida, College of Medicine in Tampa, Florida.

References

Centers for Disease Control and Prevention. Pertussis (whooping cough). Surveillance and reporting. http://www.cdc.gov/pertussis/surv-reporting.html. Accessed June 23, 2012.

Cortese

Baughman

Brown

Srivastava

. A “new age” in pertussis prevention new opportunities through adult vaccination. Am J Prev Med. 2007;32:177-185.

Centers for Disease Control and Prevention. Updated recommendations for use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine from the Advisory Committee on Immunization Practices, 2010. MMWR Morb Mortal Wkly Rep. 2011;60:13-15.

Kretsinger

Broder

Cortese

. Preventing tetanus, diphtheria, and pertussis among adults: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine recommendations of the Advisory Committee on Immunization Practices (ACIP) and recommendation of ACIP, supported by the Healthcare Infection Control Practices Advisory Committee (HICPAC), for use of Tdap among health-care personnel. MMWR Recomm Rep. 2006;55(RR-17):1-37.

Centers for Disease Control and Prevention. Tetanus and pertussis vaccination coverage among adults aged ≥18 years—United States, 1999 and 2008. MMWR Morb Mortal Wkly Rep. 2010;59:1302-1306.

Centers for Disease Control and Prevention. 2009 Adult vaccination coverage, NHIS. http://www.cdc.gov/vaccines/stats-surv/nhis/2009-nhis.htm. Accessed November 21, 2011.

Centers for Disease Control and Prevention. Adult vaccination coverage—United States, 2010. MMWR Morb Mortal Wkly Rep. 2012;61:66-72.

Grizas

Camenga

Vazquez

. Cocooning: a concept to protect young children from infectious diseases. Curr Opin Pediatr. 2012;24:92-97.

Clark

Adolphe

Davis

Cowan

Kretsinger

. Attitudes of US obstetricians toward a combined tetanus-diphtheria-acellular pertussis vaccine for adults. Infect Dis Obstet Gynecol. 2006;2006:87040.

10.

Healy

Rench

Baker

. Implementation of cocooning against pertussis in a high-risk population. Clin Infect Dis. 2011;52:157-162.

11.

Miller

Kretsinger

Euler

Ahmed

. Barriers to early uptake of tetanus, diphtheria and acellular pertussis vaccine (Tdap) among adults—United States, 2005-2007. Vaccine. 2011;29:3850-3856.

12.

Centers for Disease Control and Prevention. National Health Interview Survey. Methods. http://www.cdc.gov/nchs/nhis/methods.htm. Accessed October 28, 2011.

13.

Centers for Disease Control and Prevention. General recommendations on immunization—recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2011;60(2):1-64.

14.

Hinman

Orenstein

. Adult immunization: what can we learn from the childhood immunization program? Clin Infect Dis. 2007;44:1532-1535.

15.

Logan

. Disparities in influenza immunization among US adults. J Natl Med Assoc. 2009;101:161-166.

16.

Linn

Guralnik

Patel

. Disparities in influenza vaccine coverage in the United States, 2008. J Am Geriatr Soc. 2010;58:1333-1340.

17.

Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases. 12th ed. Washington, DC: Public Health Foundation; 2011.

18.

Wendelboe

Njamkepo

Bourillon

; Infant Pertussis Study Group. Transmission of Bordetella pertussis to young infants. Pediatr Infect Dis J. 2007;26:293-299.

19.

Euler

Harpaz

. Herpes zoster vaccination among adults aged 60 years and older, in the U.S., 2008. Am J Prev Med. 2011;40:e1-e6.

20.

Nuorti

. Pneumococcal polysaccharide vaccination among adults aged 65 years and older, U.S., 1989-2008. Am J Prev Med. 2010;39:287-295.

21.

Davis

Kretsinger

Cowan

Stokley

Clark

. New combined tetanus-diphtheria-acellular pertussis vaccines for adults: primary care physician attitudes and preferences. Hum Vaccin. 2007;3:130-134.

22.

Johnson

Nichol

Lipczynski

. Barriers to adult immunization. Am J Med. 2008;121(7 suppl 2):S28-S35.

23.

Nichol

. Improving influenza vaccination rates among adults. Cleve Clin J Med. 2006;73:1009-1015.

24.

Kempe

Hurley

Stokley

. Pneumococcal vaccination in general internal medicine practice: current practice and future possibilities. J Gen Intern Med. 2008;23:2010-2013.

25.

Petersen

Saag

Wallace

Doebbeling

. Influenza and pneumococcal vaccine receipt in older persons with chronic disease: a population-based study. Med Care. 1999;37:502-509.

26.

Wahid

Nag

Bilous

Marshall

Robinson

. Audit of influenza and pneumococcal vaccination uptake in diabetic patients attending secondary care in the Northern Region. Diabet Med. 2001;18:599-603.

27.

Carpenter

. A meta-analysis of the effectiveness of health belief model variables in predicting behavior. Health Commun. 2010;25:661-669.

Predictors of Tetanus–Diphtheria– Acellular Pertussis Vaccination Among Adults Receiving Tetanus Vaccine in the United States

Abstract

Keywords

Introduction

Methods

Results

Discussion

Footnotes

Declaration of Conflicting Interests

Funding

Author Biographies

References