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Factors influencing parents' decision on their children's vaccination against seasonal influenza : a systematic review

Meng, Yue; 孟玥 Meng, Y. [孟玥]. (2013). Factors influencing parents' decision on their children's vaccination against seasonal influenza : a systematic review. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5098800 2013

http://hdl.handle.net/10722/193841

Creative Commons: Attribution 3.0 Hong Kong License

Abstract of Project entitled

“Factors Influencing Parents’ Decision on Their

Children's Vaccination against Seasonal Influenza: A Systematic Review”

Submitted by

MENG Yue

Master of Public Health The University of Hong Kong August 2013

Introduction: Seasonal influenza is believed to be a common attribution of morbidity and mortality in the children population, and it causes huge disease burden worldwide. Although seasonal influenza vaccination is recommended as the most effective prevention by the World Health Organization and vaccination programs for children have been introduced in many countries, vaccination coverage remains low. Parents are primary decision makers for their children's immunization, therefore it is important to understand the determinants that influence parents' decision-making to provide important information for promoting vaccination uptake against seasonal influenza among children. I

Objective: To synthesize factors that influence parental decision on children's vaccination against seasonal influenza from published literature. Method: Literature reported factors that influenced parental decision on children's vaccination against seasonal influenza published before/on 31th May, 2013 were searched in PubMed and Web of Science databases. Manual searching was also performed for the citations of the retrieved papers. Both qualitative and quantitative articles consistent with the objective were searched from PubMed and Web of Science databases on 31th May, 2013. Records were screened in the sequence of title, abstract and full text to identify eligible studies, and references of eligible studies were also scrutinized to avoid missing important articles. Influencing factors were extracted from included papers, and the identified factors that influenced parental decision making were then discussed based on theoretical behavioral models. Results: Totally 32 articles met the inclusion criteria. Factors associated with parental decision included demographic factors, which consisted of parental and children’s age, parental gender, ethnicity, household income, residence, insurance status, family characters, parental education level, and children’s health history; psychological factors, including attitudes towards influenza vaccination, knowledge of influenza and vaccination, perceived risk of seasonal influenza, and emotional factors; past behaviors comprising previous frequency of using health care services, children’s seasonal influenza vaccination history, previous absenteeism from school or work, social norm referring cues to action and subjective norms; and environmental factors, meaning access to vaccination facilities. Discussion: An integrated framework based on the Health Belief Model, Triandis’ Theory of Interpersonal Behavior and the Theory of Reasoned Action was constructed to explain the findings. The framework proposes that the parents’ intention to vaccinate their children against seasonal influenza is influenced by demographic variables, attitude towards seasonal influenza vaccination, knowledge and perception of influenza/influenza vaccine, social norms (cues to II

action and subjective norms), emotion, and past behavior/experience; easy access to vaccination providers as a facilitating condition additionally determine the possibility of turning intention into actual behavior. Interventions such as providing positive knowledge relevant to seasonal influenza vaccination, targeting less intended and more influential decision-makers, ensuring sufficient access to vaccination, and creating action cues may be implemented to promote uptake of seasonal influenza vaccination among children.

III

Factors Influencing Parents’ Decision on Their Children's Vaccination against Seasonal Influenza: A Systematic Review

By

MENG Yue

A project submitted in partial fulfillment of the requirements For the degree of Master of Public Health At The University of Hong Kong August 2013

IV

Declaration

I declare that this project represents my own work, except where due acknowledgement is made, and that it has not been previously included in a thesis, dissertation or report submitted to this University or to any other institution for a degree, diploma or other qualifications.

Signed ………………………………………………………

MENG Yue

V

Acknowledgements

I would like firstly to thank my supervisor Dr. Julie Liao for her instructions about my project, all the way from proposal design to thesis modification. I am also glad to present my appreciation to the School of Public Health of The University of Hong Kong for this opportunity to gain valuable knowledge and experience, as well as the process to learn to analyze and cope with health issues as a public health professional. Acknowledgements also go to the library of the University for providing electronic resources.

VI

Table of Contents Declaration .............................................................................................................. V Acknowledgements ............................................................................................... VI Table of Contents ................................................................................................. VII List of Illustrations .............................................................................................. VIII Chapter 1 Introduction .......................................................................................... 1 1.1 Disease burden of childhood seasonal influenza .................................... 1 1.2 Childhood seasonal influenza vaccination: policy and current situation 2 1.3 Taking into parental perspectives: knowledge gaps ............................... 4 1.4 Objectives ............................................................................................... 4 Chapter 2 Methods ................................................................................................ 6 2.1 Searching strategy ................................................................................... 6 2.1.1 Inclusion Criteria ......................................................................... 6 2.1.2 Exclusion Criteria ........................................................................ 7 2.2 Analysis Approach .................................................................................. 7 2.2.1 Study selection ............................................................................. 8 2.2.2 Data extraction ............................................................................. 8 2.2.3 Result recapitulation .................................................................... 8 Chapter 3 Results ................................................................................................ 10 3.1 Demographic factors ............................................................................. 22 3.1.1 Age, gender and ethnicity .......................................................... 22 3.1.2 Social-economic factors and family characters ......................... 22 3.1.3 Parental education level ............................................................. 23 3.1.4 Children’s health history ............................................................ 24 3.2 Psychosocial factors .............................................................................. 24 3.2.1 Knowledge of influenza or influenza vaccine ........................... 24 3.2.2 Attitude towards influenza ......................................................... 24 3.2.3 Attitude towards influenza vaccination ..................................... 25 3.2.4 Emotional factors ....................................................................... 25 3.2.5 Past behavior/experience ........................................................... 26 3.2.6 Social norms .............................................................................. 26 3.3 Social-environmental factors ................................................................ 27 3.3.1 Accessibility............................................................................... 28 3.4 The relation between intention and behavior ........................................ 28 Chapter 4 Discussion .......................................................................................... 29 4.1 Vaccination intention and behavior ...................................................... 29 4.2 Integration of literature findings ........................................................... 29 4.3 Suggestions for future policy-making................................................... 36 4.4 Limitations ............................................................................................ 37 Chapter 5 Conclusion.......................................................................................... 39 References .............................................................................................................. 40 VII

List of Illustrations

Figures Figure 1. Flow Diagram of Study Selection ..................................................... 12 Figure 2. Health Belief Model .......................................................................... 32 Figure 3. Triandis’ Theory of Interpersonal Behavior ...................................... 33 Figure 4. The Theory of Reasoned Action........................................................ 34 Figure 5. Integrated Framework from HBM, TIB and TRA to explain the influences on parental decision on their children’s vaccination against seasonal influenza ........................................................................................ 35

Tables Table 1. Characteristics of included studies ..................................................... 13

VIII

Chapter 1

1.1

Introduction

Disease burden of childhood seasonal influenza

Seasonal influenza is considered as a major contributor of respiratory infections which lead to substantial morbidity and mortality annually, especially in pediatric population.

It

was

estimated

that

the

adjusted

hospitalization

rates

of

influenza-attributed acute respiratory diseases between 1997 and 1999 were around 28 to 29, 8 to 13, 2 to 6, and 1 to 2 per 1000 child-years for those who aged 1 to 2, 2 to 5, 5 to 10 and 10 to 15 years old, respectively, in Hong Kong [1]. In the US, a 25-year prospective cohort study reported an average rate of 3 to 4 annual culture-positive influenza-relevant hospitalizations per 1000 children aged below 2 years old [2]. Globally, a meta-analysis estimated that influenza-related acute lower respiratory infections accounted for 28,000 to 111,500 mortality among children aged below 5 globally in 2008 [3].

The figures above suggest the fact that seasonal influenza causes substantial disease burden to the society. From the economic perspective, laboratory-confirmed influenza infections among hospitalized children resulted into an overall median hospital cost of around $55 million [4]; another study estimated that the median cost of one influenza-caused hospitalization in children was more than 13,000 US dollars, ranging from $9,000 to $15,000 per case for low-risk and high-risk children, respectively [5]. Except for direct cost of years of life loss and health care costs, child influenza also causes indirect cost due to parental work absenteeism [6]. Data suggest that the estimated average parental work loss attributed to seasonal influenza of every 100 children less than 3 years old was 195 days [7]. Thereby, the overall disease burden of child influenza could be numerous. One study reported that seasonal influenza induced a direct medical expenditure of more than $10 billion, and an estimation of 1

$87 billion for overall economic burden in the United States annually, with approximately 15% ($1.7 billion) of direct medical cost and 5% ($4.3 billion) total burden assumed by pediatric population [8].

However, there is a potential problem of under recognized disease burden for seasonal influenza in clinical setting. It was found that only around 20% of both outpatient and inpatient children can get clinical influenza diagnosis from their physicians [9]. Moreover, children population also play a critical role in transmitting influenza to other age groups in the community, hence the overall impacts of child influenza are even greater [10]. Therefore, the real burden of disease from seasonal influenza in children population may also be underestimated.

1.2

Childhood seasonal influenza vaccination: policy and

current situation

Annual seasonal influenza vaccination is currently the most effective prevention strategy, according to the World Health Organization (WHO). A recently published meta-analysis, extracting data from 30 relevant articles, demonstrated a high efficacy of around 80% and 67% for live and inactivated vaccines respectively, together with satisfactory effectiveness varying from approximately 30% to 40% among children younger than 18 years [11].

The WHO recommends children aged 6 months to 2 years to receive annual seasonal influenza vaccination [12]. Thence, the Global Action Plan for Influenza Vaccines (GAP) strategy was established in the year 2006, setting promoting seasonal influenza vaccination coverage as its primary goal [13]. A global influenza vaccine survey conducted by WHO in 2010 reported that half of the 88 surveyed member

2

countries recommended routine influenza vaccination for children aged between 6 months to 2 years [14]. Besides, the survey also found that 16 of the 34 countries have recommended annual seasonal influenza vaccination for children aged below 16 years since the 2010-2011 influenza seasons. Nevertheless, the target age groups of children seriously vary within these countries due to their different concerns about objectives, transmission dynamic uncertainties, as well as benefit and safety of the vaccine [15].

In spite of the international trend of increasing vaccine supply and relevant policy implementation, the vaccination coverage remains suboptimal worldwide. A study [16] considered the seasonal influenza immunization rates in Europe and the United States as “generally poor”. The reason was that only 13 of 22 included European countries has met the 2006 WHO goal of 50 percent for seniors aged above 65 years, though one unique country reached the 2010 target of 75 percent. The situation for children was even worse according to the much scarcer and more incomplete available figures. Data from the US CDC reported that the coverage rate of receiving at least one dose of influenza vaccine among children aged 6 months to 18 years is 26.3%, while the coverage rates of receiving full vaccination (i.e. two doses of influenza vaccine) were 34.7% and 15.3% for those below and above 2 years old respectively in 2009-2010 season [17].

The coverage rate of seasonal influenza vaccination among children is far below the goal set. This indicates the large achievable space for future strategy improvement. Without sufficiently high immunization coverage, influenza-related disease burden could remain high. Thus, it is essential to address the main reasons behind the immunization failure among children, in order to improve coverage rates of vaccination against seasonal influenza.

3

1.3

Taking into parental perspectives: knowledge gaps

Parents or guardians are the primary decision-makers for children's immunization. Consequently, it is important to identify their concerns and the factors influencing their decision on their children's vaccination for future policy-making on improving vaccination uptake among children.

However, current understanding about this topic is quite limited. Despite a growth of research interest towards this issue in recent years, only a limited number of relevant literatures can be identified. Furthermore, no systematic review on determinants of parental decision on vaccinating their children against seasonal influenza can be identified. Existing relevant literature usually target on children with various age groups and health status, use different methods for data collection, and focus on different influences on decision-making. In addition, their sampling populations generally differed by cultural background, socio-economic status of parents, physiological conditions of children and immunity capacity of the countries. The generalization of these findings is therefore uncertain. Besides, they may fail to detect all the potential influencing factors as a whole, but only focus on one or some certain determinants. Thereby, it is necessary to synthesize the findings from existing literature and provide an overall review on factors that influence parents' decision on children's vaccination against seasonal influenza.

1.4

Objectives

In order to address the above knowledge gaps, this project aimed to answer the following research questions:

4

1. What are the factors that influence parents’ decision on vaccinating their children against seasonal influenza? 2. What theoretical models could be used to explain the influences on parental decision on children's vaccination against seasonal influenza?

5

Chapter 2

2.1

Methods

Searching strategy

Literature was primarily obtained from PubMed and Web of Science. The key words used to search relevant literature were as follows:

PubMed: #1. "Influenza, human" OR "influenza vaccine" [MeSH]; #2. "parent*" OR "mother*" OR "father*" OR "guardian*" [Title/abstract]. #1 and #2 were combined with "AND".

Web of Science: #1. Topic = ("Influenza vaccin*" OR "influenza immunization"); #2. Topic = ("parent*" OR "mother*" OR "father*" OR "guardian*"); #3. Topic = ("Child" OR "Preschool" OR "Adolescent" OR "Infant" OR "toddler" OR "teenager"). #1, #2 and #3 were combined with "AND".

The articles retrieved on the basic of above searching were firstly screened by reviewing their titles and abstracts based on the following inclusion and exclusion criteria:

2.1.1 Inclusion Criteria

The included literature should satisfy all the following inclusion criteria. (1) Population: the studies subjects are parents or guardians with at least one child 6

aged between 6 months to 18 years old; (2) Outcome: the outcomes of the studies should be parents' intention to vaccinate their children or children's vaccination status (either self-reported or actual vaccination status) against seasonal influenza; (3) Types of study: all types of original studies including qualitative studies, observation studies and experimental studies; (4) Publication Date: on or before 31st May, 2013; (5) Language: studies should be published in English; (6) Factors that influencing parents' intention to vaccinate their children or children's vaccination status (either self-reported or actual status) against seasonal influenza must be reported.

2.1.2 Exclusion Criteria

The following literature was excluded for this project. (1) Study type: editorial, letter or mathematical modeling studies should be excluded; (2) Study objective: studies aiming at medical efficacy/coverage/cost-effectiveness of vaccination, validity of parental reports comparing to medical diagnosis, or parental opinions/beliefs about a particular immunization program rather than seasonal influenza vaccination should be excluded; (3) Study result: studies that did not report parents’ opinions separately from their children’s, did not report seasonal influenza vaccination separately from other routine vaccinations, or only reported factors that influenced parental decision on children's vaccination against pandemic or avian influenza should be excluded.

2.2

Analysis Approach

7

The analysis procedure consists of three sections: study selection, data extraction, and result recapitulation.

2.2.1 Study selection

All literature retrieved based on the above searching strategies were screened by the candidate of this project alone. First, the titles and abstracts of all retrieved literature were evaluated based on the inclusion and exclusion criteria for potential inclusion in the project. Hereafter, full text of eligible literature was carefully reviewed and determined whether to be finally included in the project or not. References of eligible articles were also scrutinized manually to avoid omission of important relevant studies.

2.2.2 Data extraction

After determining included studies, the following information was extracted from each included study, including authors, year of publication, country where the study were conducted, study design, theoretical model used, targeted period, sample size, targeted parental population and children's ages, children's health conditions, outcomes including parents' intention to vaccinate their children and/or children's actual vaccination status (either self-reported or actual status) of seasonal influenza, statistical methods used to examine the associations between identified influences and vaccination outcomes, theoretical behavioral model used, and reported factors that influenced vaccination outcomes.

2.2.3 Result recapitulation

8

Finally, findings were discussed based on behavioral theories, aiming to construct a comprehensive framework to understand factors that impact parental decision-making for children's vaccination against seasonal influenza.

Instead of choosing a single behavioral model, an integration of several models was applied to discuss the findings. The reason is that using a single model to predict a certain behavior has been frequently criticized for missing important factors. For example, the health belief model (HBM) has been criticized for not accommodating the influence of emotion and social norms. Besides, a single model usually can only explain limited proportion of variance in behavioral change. As a consequence, using integrated models or a modified version of an original model has been encouraged and found to be able to improve prediction of behavioral change. For instance, the original HBM can only account for around 20% [18] of the variance of health-related behaviors. Similarly, approximately 27% to 39% [19] of the variance in behavior and intention respectively were reported across a variety of health behaviors based on the original Theory of Planned Behavior (TPB); meanwhile, an extended TPB model was found to be able to explain totally 48.2% [20] of variance in vaccination uptake among elderly population and 60% [21] of adults' intention.

9

Chapter 3

Results

The literature search identified 164 and 279 records in PubMed and Web of Science databases, respectively. Finally, 32 studies were confirmed as eligible based on the inclusion and exclusion criteria. The detailed workflow of study selection is diagramed in Figure 1.

Included studies were conducted in Australia, Canada, France, Italy, Kenya, Spain, Taiwan, Turkey, the United Kingdom and the USA (listed in alphabetical order), published between 1992 and 2012. Of the 32 included studies, 30 were quantitative studies, one was qualitative study, and one combined both. Among the 30 quantitative studies, 27 were observational survey that explored influencing factors of vaccination behavior and/or vaccination intention, including 21 cross-sectional and 6 longitudinal studies; while the other four were experimental studies that estimated the effect of a particular intervention on vaccination coverage.

Totally 30 studies reported seasonal influenza vaccination status of the children. Among them, eight were confirmed with medical record while the other twenty-two were only based on the report from parents. The reported vaccination uptakes ranged between 5.1 percent [22] and 86 percent [23]. A total of 6 studies reported parents' intention to immunize their children. The intention to vaccinate children against seasonal influenza ranged from 22 percent [24] to 91.7 percent [25]. Thirteen studies mentioned to the application of theoretical behavioral models in questionnaire design. The theories used included the Health Belief Model [26-33], the Theory of Reasoned Action (especially the Triandis model) [28, 32, 34-37], and the framework of Aday and Andersen (the framework for the study of access to medical care) [38].

10

Table 1 illustrated the primary characteristics of each included study. Factors that reported to have influenced parents' decisions (including intention to vaccinate and actual vaccinating children against seasonal influenza) were identified and summarized as well. According to the results, determinants were organized into demographic, psychological and social-environmental influences.

11

Records excluded (N=402): For irrelevancy (N=380); For duplicate (N=22). Title and abstract screening (N=41)

Identification

Screening

Science database searching results (N=279)

PubMed database searching results (N=164)

Included (N=32)

Figure 1.

Flow Diagram of Study Selection

12

Included

Full-text articles assessment for eligibility (N=40)

Full-text articles excluded (N=8): A mix of opinions from children and guardians (N=1); Focusing on a particular immunization program rather than vaccination (N=3); A mix of other objectives with seasonal influenza vaccination in results (N=2); A failure to provide data on determinants (N=2).

Eligibility

Record excluded for no full-text source available (N=1)

Table 1.

Author &

Characteristics of included studies

Country/regi Study design &

Published

Theoretical Sample size &

on & Method of Data

year

Targeted collection

(ref. No.)

Statistical

behavioral

vaccination intention

model**

model

and/or status

Population

Influencing factors***

characteristics period

Allison et al.

Cross-sectional study,

USA,

N=259,

Logistic

Health Belief

Behavior: 26%;

Positive: social norm, high perceived benefits of vaccination, discussion with

2010 [26]

self-administered

2008-2009

parents of elementary

regression

Model

Intention: 24%

a doctor, high perceived safety of the vaccination, high perceived

survey

season

school-aged children

susceptibility to influenza. Negative: time, inconvenience, and cost of vaccination.

Chen et al.

Cross-sectional study,

Taiwan,

N=2778,

Logistic

Health Belief

Behavior: overall

Positive: younger parents, currently being employed, residence in rural or

2011 [27]

self-administered

no specific

parents of 6m-36m

regression

Model

60.4%

mountainous areas, children’s history of chronic disease and history of

survey

season

children with/without

hospitalization due to influenza, high perceived susceptibility to influenza,

chronic disease

high perceived benefits of vaccination, and cues to action. Negative: perceived barriers including misunderstanding, cost, inconvenience, side effects of vaccination.

Daley et al.

Prospective cohort

USA,

N=926,

Generalize

2005 [39]

study,

2002-2003

parents of 6m-72m

telephone survey

season

children with ≥1 high

Not stated

Behavior: 22%

Positive: having private insurance.

d linear

(asthma), 26% (other

Negative: lack of a physician's recommendation, low perceived susceptibility

models

HRCs)

to influenza.

Behavior: 71%

Positive: social norm.

risk medical conditions

Daley et al.

Cross-sectional study,

USA,

N=472,

Logistic

Health Belief

13

2006 [28]

telephone survey

2003-2004

parents of 6m-21m

season

healthy children

regression

Model,

Negative: older children, having only public or no insurance, perceived

Theory of

barriers to vaccination including cost and inconvenience of vaccination.

Reasoned Action

Daley et al.

Cross-sectional study,

USA,

N=316,

Logistic

Health Belief

2007 [29]

telephone survey

2003-2004

parents of 6m-21m

regression

Model

season

healthy children

Behavior: 82%

Positive: physician's recommendation, social norm. Negative: perceived barriers including supply and quality of vaccines, time, occasion, cost, inconvenience of vaccination and the difficulty in making appointment, lower parental education level, intention not to immunize in previous seasons.

Flood et al.

Cross-sectional study,

USA,

N=500,

One-way

Health Belief

Behavior: overall

Positive: higher parental education level, female parents, high perceived

2010 [30]

web-based survey

no specific

parents of 2y-12y

ANOVA

Model

65.8% (ever);

benefits of vaccination, and physician's recommendation.

season

children with/without

Intention: 69.4%

Negative: low perceived safety of vaccination, low perceived susceptibility to

chronic disease

(≥medium)

influenza.

Behavior: 5.4%

Positive: a computerized reminder letter in addition to an autodial recall

(baseline), 32.1%

telephone message, children with asthma with more clinic visits for acute

(after).

respiratory illnesses in between influenza seasons.

Gaglani et al.

Clinical trial,

USA,

N=925,

Poisson

2001 [40]

data from medical

1996-1997,

parents of 6m-18y

regression

review

1997-1998

children with asthma

seasons

or reactive airway

Not stated

disease

Gnanasekaran

Prospective cohort

USA,

N=2140,

Logistic

Health Belief

Behavior: 27%

Positive: younger children, physician’s recommendations, knowledge about

et al.

study,

2002-2003,

parents of 5y-18y

regression

Model

(2002–03),

the availability of vaccines, high perceived efficacy and safety of vaccination,

2006 [31]

telephone survey

2003-2004

children with asthma

43% (2003–04).

media attention.

14

seasons

Negative: being African American or other non-white race/ethnicity, lower household income, single parent households.

Gnanasekaran

Cross-sectional study,

USA,

N=1058,

Logistic

et al.

telephone survey

1999-2000

parents of 2y-16y

regression

season

children with asthma

2006 [41]

Not stated

Behavior: 16%

Positive: children with persistent asthma, hospitalization during the follow-up year. Negative: older children, lower parental education level.

in Medicaid managed care

Grant et al.

Cross-sectional study,

Canada,

N=203,

Logistic

2003 [42]

interviewer-

2000-2001

parents of 6m-18y

regression

administered survey

season

children

Humiston et

Cross-sectional study,

USA,

N=153,

Logistic

al.

interviewer-

2003-2004

English-speaking

regression

2005 [43]

administered survey

season

parents of 6m-23m

Not stated

Behavior: 27%

Positive: children with chronic diseases, discussion about vaccination with a physician.

Not stated

Intention: 78%

Positive: high perceived severity of influenza, high perceived safety and necessity of vaccination. Negative: higher parental education level.

children

Lin et al.

Prospective cohort

USA,

N=447,

Logistic

Theory of

Behavior: 44%

Positive: high perceived necessity of influenza vaccination for asthmatic

2006 [34]

study,

2002-2003,

parents of 2y-13y

regression

Reasoned

(2003), 25% (2004).

children, positive attitudes towards influenza vaccination, perceived benefit

mailed survey

2003-2004

children with

Action

of influenza vaccination, physician's recommendation, relatives' and parents'

seasons

high-risk medical

(especially

own belief that the child should be vaccinated, easy access to vaccination,

conditions, from

the Triandis

receipt of a reminder from the doctor’s office.

low-income urban

model)

population

15

Lin et al.

Cross-sectional study,

USA,

N=183,

Logistic

Theory of

Behavior: 30.6%

Positive: households with fewer children, parents' positive attitudes towards

2006 [35]

mailed survey

2002-2003

parents of 2y-13y

regression

Reasoned

vaccine; physician’s recommendation, relatives' recommendation.

season

children with

Action

Negative: low perceived efficacy of vaccine.

high-risk medical

(especially

conditions, from

the Triandis

low-income urban

model)

population

Ma et al.

Cross-sectional study,

USA,

N=256,

Logistic

2006 [44]

interviewer-

2003-2004

parents of 6m-59m

regression

administered survey

season

children with/without

Not stated

Behavior: 38%

Positive: media coverage, physician’s recommendation.

Not stated

Behavior: 42%

Positive: physician’s recommendation.

chronic disease

Mirza et al.

Cross-sectional study,

USA,

N=794,

Logistic

2008 [45]

mailed survey

2002-2003,

parents of middle

regression

2003-2004

school students

Negative: low perceived safety of vaccination.

seasons

Moore et al.

Clinical trial,

USA,

N=934,

2 test or

2006 [46]

vaccination records

2004-2005

parents of 6m-18y

from medical review

season

Nettleman, et

Cross-sectional study,

al.

mailed survey

Not stated

Behavior: 58%

Positive written notification combined with verbal notification rather than

Fisher’s

(intervention), 44%

verbal notification alone

children with asthma

exact test

(control).

USA,

N=954,

2 test

no specific

parents of elementary

Not stated

Intention: 30%

Positive: previous school absenteeism and parental work loss due to children's influenza history.

16

2001 [47]

season

school students

Nowalk et al.

Prospective cohort

USA,

N=417 (2003),

Logistic

Theory of

Behavior: 56%

Positive: receipt of a reminder letter from doctor’s office, physician’s

2005 [36]

study,

2002–2003,

N=266 (2004),

regression

Reasoned

(2003), 45% (2004).

recommendation.

mailed survey

2003–2004

parents of 6m-23m

Action

seasons

children from

(especially

inner-city,

the Triandis

low-income and

model)

minority population

Nowalk et al.

Cross-sectional study,

USA,

N=436,

Logistic

Theory of

Behavior:

Positive: physician's recommendation, positive attitudes towards influenza

2007 [37]

mailed survey

2002-2003

parents of 6m-23m

regression

Reasoned

43.20%

vaccination.

season

children from

Action

Negative: perceived more trouble than benefits regarding influenza

inner-city,

(especially

vaccination.

low-income and

the Triandis

minority population

model)

Oria et al.

Cross-sectional study,

Kenya,

N=3193

2013 [25]

interviewer-

2010–2011

administered survey and

season

focus group discussion

Not stated

Not stated

Intention: 91.7%;

Positive: perceived benefits of vaccination.

(pre-vaccination),

Behavior:

Negative: low perceived safety of vaccination, low perceived severity of

N=2091

31.2% (fully

influenza, time and occasion of vaccination.

(post-vaccination)

vaccinated), 11.1%

parents of