Vaccine 31 (2013) 5466–5470
Contents lists available at ScienceDirect
Vaccine
journal homepage: www.elsevier.com/locate/vaccine
How parents make decisions about their children’s vaccinations
Emily K. Brunson ∗
Department of Anthropology, Texas State University, 601 University Dr., San Marcos, TX 78666, USA
a r t i c l e
i n f o
Article history:
Received 15 May 2013
Received in revised form 17 August 2013
Accepted 28 August 2013
Available online 25 September 2013
Keywords:
Vaccination
Parents
Decision-making
Qualitative research
a b s t r a c t
Background: Continued parental acceptance of childhood vaccination is essential for the maintenance of
herd immunity and disease prevention. As such, understanding parents’ decision-making in relation to
their children’s vaccinations is vitally important.
Objective: This qualitative study sought to develop an understanding of the general process parents go
through when making decisions about their children’s vaccinations.
Methods: Interviews were conducted with U.S.-born parents living in King County, Washington who had
children ≤18 months of age. These interviews were recorded and transcribed verbatim.
Results: Through the application of grounded theory, a general decision-making process was identified.
Stages in this process included: awareness, assessing and choosing, followed by either stasis or ongoing
assessment. The greatest variation occurred during the assessing stage, which involved parents examining vaccination-related issues to make subsequent decisions. This research suggests that three general
assessment groups exist: acceptors, who rely primarily on general social norms to make their vaccination
decisions; reliers, who rely primarily on other people for information and advice; and searchers, who seek
for information on their own, primarily from published sources.
Conclusions: These results imply that one-size-fits-all approaches to vaccination interventions are inappropriate. Instead, this research suggests that interventions must be targeted to parents based on how
they assess vaccination.
© 2013 Elsevier Ltd. All rights reserved.
1. Introduction
Vaccination is meant to prevent disease, and according to recent
studies it is extremely successful at doing so [1,2]. This success,
however, is precarious. It depends on the maintenance of herd
immunity, which in turn depends on the continued acceptance of
vaccination, particularly among parents who must decide whether
or not to vaccinate their children.
In an effort to understand why some parents do not accept
complete and on-time vaccination, research has been conducted
on a variety of topics including: parents’ knowledge, attitudes
and beliefs about vaccines and vaccine-preventable diseases (VPD)
[3–9]; the role health care providers play in parents’ decisionmaking [10–13]; and parents’ perceptions of and experiences with
barriers to vaccination [14–20]. While this research offers valuable insights into particular aspects of parents’ decision-making,
less research has been conducted on how parents actually reach
their vaccination decisions. This paper describes the results of a
Abbreviations: VPD, vaccine preventable diseases.
∗ Tel.: +1 512 245 6753; fax: +1 512 245 8076.
E-mail address: [email protected]
0264-410X/$ – see front matter © 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.vaccine.2013.08.104
qualitative study that examined parents’ vaccination decisionmaking in order to develop a clearer understanding of this process.
2. Methods
Data for this study were drawn from interviews with parents. Participation was limited to U.S.-born parents whose children
were ≤18 months of age. These recruitment criteria were chosen
to ensure comparability in the sample. Participation was further
limited to parents living in King County, Washington, a large,
diverse county in western Washington State, historically known
for lower than average vaccination rates [21,22].
Parents were recruited to participate through a variety of methods including: flyers hung in parks and community centers, emails
sent to parenting listservs, and short presentations made to community groups. All interviews were conducted by the author, an
anthropologist, and were recorded and transcribed verbatim. The
protocols of this study were approved by the University of Washington IRB.
Grounded theory, particularly as described by Charmaz [23],
informed both the data collection and analysis in this study. Following the tenants of this approach, the initial recruitment of parents
was purposeful to ensure a sample of parents who made all types
of vaccination decisions and who were also diverse in terms of
E.K. Brunson / Vaccine 31 (2013) 5466–5470
5467
Table 1
Parents’ and children’s demographic characteristics.
Parents’ demographic characteristicsa
Fig. 1. The model of parents’ decision-making process.
age, education and income; characteristics that previous studies
[22,24–27] suggested play a role in vaccination decision-making.
Interviews with parents at this stage were open-ended and focused
on how parents reached their vaccination decisions.
In compliance with the methodology of grounded theory, coding occurred simultaneously with data collection. Initial coding was
open and close to the text, meaning that codes were developed to
reflect the actions, intentions and meanings of the respondents,
often using their own words. As additional interview texts were
coded, constant comparison provided a means to group similar
codes into categories.
Once preliminary categories were identified, recruitment of
participants shifted from selecting a diverse sample to selecting
participants who were able to provide insights that addressed
specific questions identified in the emerging analysis. Called theoretical sampling, this process also resulted in the development of
more focused interview questions. Topics explored in the resulting semi-structured interviews included: the steps parents took to
reach their vaccination decisions, the sources of information they
considered, their feelings about their current vaccination decisions
and their future vaccination plans. Data collection continued in this
vein until all questions in the emerging analysis were answered and
the resulting model was fully developed.
Analysis at this stage continued to occur simultaneously with
data collection. Coding, however, moved from open, close coding to
theoretical coding, which involved making comparisons between
codes and categories and categories and categories in order to
further define them. Memo-writing, including model drawing,
facilitated these comparisons. This process ultimately led to the
development of the theoretical model presented in this paper.
As a final step to evaluate the validity of the results, 4 parents
who participated in interviews were asked to read and comment
on the model. These parents were diverse in terms of their vaccination decisions and were generally representative of the larger
sample. Additionally, 4 parents who were not included in any part
of this research were also asked to read and comment. After parents’ responses were received they were carefully considered, and
as a result a few minor adjustments were made.
3. Results
Interviews were conducted with 15 mothers and 3 couples
(Table 1). The findings of this research suggest that the process of
parents’ vaccination decision-making is complex, but that a general
process does exist (Fig. 1).
3.1. Pre-decision making factors
Parents do not enter the vaccination decision-making process
as blank slates; their personalities, backgrounds, and previous
life experiences influence their decision-making as well as the
decisions they ultimately reach. While life experiences are highly
Age range (in years)
Percent white
Highest level of education (percent)
Less than high school
High school
Some college
Atleast a BA/BS
Household income (percent)
<$25,000
$25–50,000
$50–75,000
$75–100,000
>$100,000
18–40 (29 median)
83.3
5.5
5.5
11.1
77.8
16.7
22.2
11.1
16.7
33.3
Children’s demographic characteristics
Age range (in months)
Percent first born
Percent male
Vaccination status (percent)
Completely vaccinated
Partly vaccinated
Completely unvaccinated
Type of health insurance (percent)
Private
Medicare/Medicaid
No insurance
3–18 (8 median)
55.6
44.4
38.9
38.9
22.2
61.1
33.3
5.5
a
When couples were interviewed, only data from the parent self-selected to be
the parent most responsible for making the vaccination decisions is included in this
table.
individualized – it is unlikely that any two parents will have identical experiences let alone identical reactions to them – there was one
pre-decision making factor that all participants in this research had
in common and that was highly influential in the ultimate decisions
many of them reached: exposure to general social norms.
Using the definition of norms provided by Ellickson [28], that
norms are behaviors considered “normal” and behaviors that
enforced by some type of social punishment, it is clear that vaccinating was the general social norm for participants in this study.
The idea that childhood vaccination is normal was pervasive in
the interviews. Using words such as “normal,” “the right thing,”
and “natural,” participants who made all types of vaccination decisions routinely described childhood vaccination as a customary and
expected part of life; as one participant described: “It felt natural,
it’s like you’re just supposed to do it.”
The existence of social punishments was also apparent. Many
vaccinating participants expressed negative opinions about parents
who did not completely vaccinate and in some cases even anger.
Using words like “lazy,” “selfish,” and “irresponsible,” these participants suggested that parents who did not vaccinate were not
doing what was right for the community or their individual children. These negative opinions, in turn, impacted relationships, as
one participant explained: “I don’t talk about it [partially vaccinating]. When I did one of my friends started saying ‘That’s crazy!
You’ve got to get vaccinated’ and ‘I can’t believe you wouldn’t do
that.’ So I don’t talk about it anymore. I don’t want my friends to
judge me.”
3.2. Awareness
Actual decision-making begins when parents enter the awareness stage and become cognizant of vaccination as an issue that
directly impacts their children. While parents may have a general
concept of vaccination prior to this point, until they consider their
own children’s vaccinations they have not entered the awareness
stage. Once parents become aware of vaccination in this way, they
5468
E.K. Brunson / Vaccine 31 (2013) 5466–5470
Table 2
Characteristics of the different assessing groups.
Importance of
General social norms
Social network norms
Sources of information
Social networks (friends, family, etc.)
Published sources (books, etc.)
Level of critical assessment
Key characteristics of this group
Acceptors
Reliers
Searchers
Extremely important
n/a
Slightly important
Extremely important
Not important
Not important
n/a
n/a
n/a
Acceptors rely on general social norms
as the basis of their decisions. They
accept these norms with little or no
questioning. They do not investigate
vaccination.
A key source of information
A minor source of information
Slightly critical
Reliers tend to turn to others for
information and advice. While reliers
may investigate vaccination
themselves they tend to do so only
superficially.
Not a likely source of information
A key source of information
Extremely critical
Searchers seek to find out about
vaccinations for themselves. They
consider multiple sources of
information and are highly critical of
the information they obtain.
do not need to become re-aware. Thus the awareness phase is only
experienced by first-time parents.
Awareness happens at various times for different parents. In this
study, some participants became aware of vaccination before they
were ever pregnant. Most participants, however, become aware of
vaccination later, either during their pregnancies or shortly after
the births of their children.
3.3. Assessing
After parents become aware, they enter the assessing phase.
Assessing involves examining issues related to vaccination so that
decisions can be made. While all parents go through the assessing
phase, the ways in which they do so are profoundly different.
This research suggests that parents’ assessing of vaccination occurs along a continuum, ranging from extremely minimal
assessing on one end to highly informed and involved assessing
on the other. While individual parents may occupy short or
extended ranges along this continuum, three primary divisions
exist (Table 2): parents who completely accept general social norms
(acceptors), parents who rely on others (reliers), and parents who
actively search for themselves (searchers). Due to the considerable differences between these groups, additional information on
assessing will be considered in light of each of these groups.
3.3.1. Acceptors
Assessing for acceptors is extremely minimal, almost to the
point of being absent. The primary consideration for this group is
knowledge of general social norms, which in this U.S.-based population was strongly pro-vaccination. Acceptors tend to accept these
norms with little or no questioning. Thus, acceptors do not investigate vaccination per se. Instead they assume that there is one right
decision to make and that everyone else is making that decision; as
one vaccinating participant explained: “It wasn’t a big deal! Everybody gets [vaccines]. When I was little I got them and my brothers
and sisters got them. We all got them. It’s just something that people
do.” These sentiments were seconded by another participant who
stated: “It wasn’t something I spent a lot of time thinking about
because I just assumed it was a no brainer. I knew I had to do it.”
A consequence of passively assessing vaccination in this way is
that acceptors tend to be uninformed. This includes being uninformed about the diseases vaccines protect against and when
vaccines are meant to be administered. Some of the claims made by
acceptors in this study included that most vaccinations are given to
10–12 year-olds, that vaccines are given to prevent bubonic plague,
and that smallpox vaccinations are still required for school entry.
3.3.2. Reliers
Assessment for reliers is active, as opposed to the passive assessment of parents in the accepting category. While knowledge of
general social norms remains important for reliers, parents in this
group are also keenly aware of the norms espoused by their own
social networks. In this way, reliers’ perceptions of others’ decisions
play a significant role in their own decision-making; as one vaccinating participant explained: “Everyone I know has gotten their
kids vaccinated and that’s kind of a big influence, you know, just
seeing that everyone else is doing this.”
Besides being aware of the norms espoused by the people
in their own social networks, reliers also depend on these individuals for information, direction and advice about vaccination,
as a completely non-vaccinating participant stated: “I started
[researching vaccination] by asking people, mainly my friends what
they thought. Then I asked the pediatrician.” While some reliers
may also consult additional sources of information such as the
Internet, magazines and books, this is secondary to consulting with
those around them, as another participant explained: “My mom
sent me a book and I read parts of it and then I just stopped. I thought
once she’s born I’ll read it but I haven’t. And then, you know, you
meet other new moms and I did talk to some of them about it and
that’s why I decided to vaccinate.”
The final characteristic of reliers is that they tend to be uncritical, or only minimally critical, of the information and advice they
receive, as yet another participant explained: “At the two week
check-up I think [the pediatrician] was the one who was like ‘OK
you’ll come back at two months for a check-up and vaccinations.’
And he didn’t even ask did we want to or not want to. And I didn’t
ask. Honestly, I just trusted that he knew what was best for my son.”
Only in cases where reliers have already made their decisions are
they likely to reject information or advice from people they would
otherwise trust. In this way, reliers are more likely to reject alternative perspectives outright, whether in favor of vaccinating or not
vaccinating, without really considering them first.
3.3.3. Searchers
Unlike assessment in the previously mentioned groups, assessment for searchers is both active and highly involved. While
searchers are aware of general social norms and the norms of
their social networks, this knowledge has little influence on their
own decision-making. As one completely non-vaccinating couple
explained:
Participant 1: People tell us that we’re privileged to make this
decision, that we shouldn’t do it. But I’m like he’s our kid so we’re
going to make the best decisions we can for him.
Participant 2: Yeah and not because of any society pressure.
Likewise, searchers tend to not rely on others for advice, insights
or information. Instead they conduct their own research, primarily through seeking information from published sources including
government websites, books and even the primary literature. While
they may also consult with a few, often carefully chosen, individuals, this is secondary to finding and evaluating information on
their own, as one partially vaccinating participant described: “It
was a long, drawn out process. I mean we went back and forth and
E.K. Brunson / Vaccine 31 (2013) 5466–5470
argued a little bit and we made worksheets and we read books and
went to workshops and brought back information. And then I found
this naturopath who’s known for her expertise in vaccinations and
I’ve talked to her about what to do next.”
Searchers also tend to be critical of the information they obtain,
as exemplified by one participant’s description of the research
relating to the MMR vaccine and autism: “Like the British study that
everybody uses that does have concerns about [the link between
the MMR vaccine and autism] it was very faulty. I mean 12 children and then several of the people involved have come forward
and agreed that there was no evidence for what they came up with.”
For searchers, this critical examination generally extends to sources
for and against vaccination. Unlike reliers, searchers tend to not
dismiss alternative perspectives without considering them first.
5469
or additive, as one participant explained: “I’ve kind of gone through
each one and eliminated them in my mind. ‘Yeah we don’t want this.
Yeah we don’t need this.’ But that tetanus one keeps popping up in
my head. It doesn’t necessarily make me feel like I need to give it to
her, but I’m still learning more. All the other ones I’m pretty much
like [no] but that one I’m still learning more about.”
Once parents are in the ongoing assessment phase they can stay
there in perpetuity, or they can transition into the stasis phase. This
transition can occur at any time. Some participants in this study
stayed in the ongoing assessment phase for only a few months after
the births of their first children, others stayed in this phase for years,
even after the births of subsequent children.
4. Discussion and conclusions
3.4. Choosing
After assessing vaccination, parents enter the choosing phase.
When choosing parents have several options: on the most basic
level they can accept, delay or reject vaccination. Parents can also
opt to make blanket vaccination decisions, for example their children will receive all of the required vaccines according to the
recommended schedule, they can choose to make decisions on
a vaccine-by-vaccine basis, or they can opt to do something in
between. As with assessing, when choosing occurs varies from parent to parent. In this study some participants made their choices
well in advance, while others held off choosing until the moment
vaccines were offered.
3.5. Stasis, reassessment and ongoing assessment
After making initial choices about vaccination, parents enter one
of two categories: stasis or ongoing assessment. In stasis, parents’
vaccination decisions remain static. Changes to decisions are not
ruled out, but for the present parents plan to keep doing whatever
they are doing, as one participant explained: “I’m happy with what
we’ve decided and unless something comes up that won’t change.”
Parents can enter the stasis phase at any time and they can stay
there indefinitely, even after the births of subsequent children. As
one participant who had recently had her third child explained:
“I did what I did before. I got all of my other girls vaccinated so of
course I didn’t have to figure it out again.” Parents in the stasis phase
can also transition out of this category and re-enter the assessing
phase. This transition is reassessment.
Reasons for reassessing are numerous. For participants transitioning to vaccinating, reasons provided in this research included
having pro-vaccination conversations with others, discovering new
information about vaccines or VPD, and believing children’s risks
have changed due to increasing age, school entry or travel to foreign countries. For participants transitioning to not vaccinating,
reasons for reassessment included feeling a growing concern about
the increasing number of vaccinations; having children experience
bad reactions to vaccines; and learning about exemptions to vaccination requirements. It is also possible for parents to reassess and
ultimately make the same decisions they made before, for example
when parents become aware of a vaccine they did not previously
know about but ultimately decide to do what they have done in the
past.
As an alternative to entering the stasis phase, parents have the
option of staying in the assessment phase after they make their initial vaccination decisions. This is ongoing assessment. Parents in the
ongoing assessment phase continue to assess issues related to vaccination, although the particular issues vary. While some continue
to assess vaccination generally, others only continue to consider
vaccinations as they are offered to their children, and yet others
only continue to assess specific topics such as a particular vaccine
Previous research has focused on a variety of topics relating to
parents’ vaccination decisions [3–20]. While the findings of these
studies offer valuable insights that have and continue to inform
interventions aimed at improving vaccination rates, there is an
implicit assumption that parents develop their understandings, for
example a particular belief about VPDs or a certain level of hesitancy toward vaccination, in the same way. The research presented
in this paper suggests this is not always the case.
While parents go through a general process to make decisions
about their children’s vaccinations, how they do so, and particularly
how they assess vaccination, varies. Thus, in addition to considering parents’ understandings, like their beliefs or levels of hesitancy,
this research suggests that it is important for researchers and those
developing interventions to consider how parents came to these
understandings in the first place – if they accepted general social
norms regarding vaccination, if they relied on others for information or advice, or if they searched published sources like books
or the primary literature. In other words, understanding how parents make their vaccination decisions is an important foundational
component to understanding why parents make the vaccination
decisions that they do and to developing effective interventions.
In relation to interventions specifically, previous research has
noted the importance of social norms in regards to parents’ vaccination decision-making [7,29–33]. This study also found that social
norms play a key role, particularly in the assessments of acceptors
and reliers. Thus, in order to maintain or improve vaccination rates
among parents in these groups, it is imperative that interventions
are targeted broadly so that they (1) function to maintain a general
pro-vaccination social norm (important for parents in both groups)
and (2) incorporate the people parents are likely to include in their
social networks such as their spouses/partners, family members
and friends (important for reliers). If this is not done, it is almost
certain that vaccination rates in these groups will not improve and
it is even possible that rates will decrease [31,34,35]. Examples of
this happening can already be found in some communities in the
U.S. and countries around the world [34–40].
Unlike assessment in the accepting and relying groups, assessment in the searching group is not based on social norms. Instead
assessment for parents in this group is primarily based on critical
evaluations of published sources. In relation to interventions, this
type of assessment necessitates that intervention materials be provided to parents in published form and that the materials provide
specific information about vaccination and related topics. Additionally, because searchers tend to be critical of the information they
obtain, intervention materials would also benefit from the following characteristics: evidence provided for the conclusions reached,
a lack of opinions and/or scare tactics, a balanced perspective that
realistically considers the multiple types of risks involved and a
recognition that not everything about immunity, vaccines or VPD
is known. By targeting interventions in this way, the intervention
5470
E.K. Brunson / Vaccine 31 (2013) 5466–5470
materials will be more likely to both reach and influence searchers
and thus maintain or even improve vaccination rates among parents in this group.
The findings of this research should be interpreted in light of a
few limitations. First, qualitative research is inherently ungeneralizable. This means that the results of this study may not be
representative of parents in King County or of parents nationally. Second, the research was limited to U.S.-born parents. Thus,
the experiences of immigrant groups are not represented in this
research. Finally, this study used cross-sectional data to develop
a longitudinal model of parents’ decision-making. Future research,
including longitudinal qualitative research, studies of different cultural groups and validation of this study’s results through survey
research with a larger population, would go far in addressing these
limitations and in expanding the understanding of how parents
make decisions about their children’s vaccinations.
In conclusion, this research suggests that one-size-fits-all
approaches to vaccination interventions are inappropriate. Instead,
this research suggests that interventions must be targeted based
on how parents assess vaccination, in additional to other topics of
interest such as parents’ knowledge, attitudes, beliefs or levels of
hesitancy.
References
[1] WHO. GIVS. Global Immunization Vision and Strategy 2006–2015. Geneva:
WHO; 2012. Available at: http://www.who.int/immunization/givs/en/
index.html [accessed 10.12.12].
[2] Roush SW, Murphy TV, The Vaccine-Preventable Disease Table Working Group.
Historical comparisons of morbidity and mortality for vaccine-preventable disease in the United States. J Am Med Assoc 2007;298(18):2155–63.
[3] Raithatha N, Holland R, Gerrard S, Harvey I. A qualitative investigation of vaccine risk perception amongst parents who immunize their children: a matter
of public health concern. J Public Health Med 2003;25(2):161–4.
[4] Gust D, Brown C, Sheedy K, Hibbs B, Weaver D, Nowak G. Immunization attitudes and beliefs among parents: beyond a dichotomous perspective. Am J
Health Behav 2005;29(1):81–92.
[5] Hilton S, Petticrew M, Hunt K. ‘Combined vaccines are like a sudden onslaught
to the body’s immune system’: parental concerns about vaccine ‘overload’ and
‘immune-vulnerability’. Vaccine 2006;34:4321–7.
[6] Serpell L, Green J. Parental decision-making in childhood vaccination. Vaccine
2006;24:4041–6.
[7] Gust DA, Darling N, Kennedy A, Schwartz B. Parents with doubts about vaccines:
which vaccines and why. Pediatrics 2008;122(4):718–25.
[8] Kennedy A, LaVail K, Nowak G, Basket M, Landry S. Confidence about vaccines in the United States: understanding parents’ perceptions. Health Affair
2011;30(6):1151–9.
[9] Smith PJ, Humiston SG, Marcuse EK, Zhao Z, Dorell CG, Howes C, et al.
Parental delay or refusal of vaccine doses, childhood vaccination coverage at 24
months of age, and the health belief model. Public Health Rep 2011;126(S2):
135–46.
[10] Fredrickson DD, Davis TC, Arnold CL, Kennen EM, Hurniston SG, Cross JT, et al.
Childhood immunization refusal: provider and parent perceptions. Fam Med
2004;36(6):431–9.
[11] Smith PJ, Kennedy AM, Wooten K, Gust DA, Pickering LK. Association between
health care providers’ influence on parents who have concerns about vaccine
safety and vaccination coverage. Pediatrics 2006;118(5):1287–92.
[12] Gullion JS, Henry L, Gullion G. Deciding to opt out of childhood vaccination
mandates. Public Health Nurs 2008;25(5):401–8.
[13] Plumridge E, Goodyear-Smith FA, Ross J. Parents and nurses during the immunization of children – where is the power? A conversation analysis. Fam Pract
2008;25(1):14–9.
[14] Keane V, Stanton B, Horton L, Aronson R, Galbraith J, Hughart N. Perceptions
of vaccine efficacy, illness, and health among inner-city parents. Clin Pediatr
1993;32(1):2–7.
[15] Lannon C, Brack V, Stuart J, Caplow M, McNeill A, Bordley WC, et al. What mothers say about why poor children fall behind on immunizations. Arch Pediatr
Adolesc Med 1995;149:1070–5.
[16] McCormick LK, Bartholomew LK, Lewis MJ, Brown MW, Hanson IC.
Parental perceptions of barriers to childhood immunization: results of focus
groups conducted in an urban population. Health Educ Res 1997;12(3):
355–62.
[17] Bates AS, Wolinsky FD. Personal, financial, and structural barriers to
immunization in socioeconomically disadvantaged urban children. Pediatrics
1998;101(4):591–6.
[18] Luman ET, McCauley MM, Shefer A, Chu SY. Maternal characteristics associated
with vaccination of young children. Pediatrics 2003;111(5):1215–8.
[19] Falagas ME, Zarkadoulia E. Factors associated with suboptimal compliance to
vaccinations in children in developed countries: a systematic review. Curr Med
Res Opin 2008;24(6):1719–41.
[20] Feemster KA, Spain CV, Eberhart M, Pati S, Watson B. Identifying infants at
increased risk for late initiation of immunizations: maternal and provider characteristics. Public Health Rep 2009;124(1):42–53.
[21] CDC. MMWR 2011;60(34):1157–63.
[22] Smith PJ, Chu SY, Barker LE. Children who have received no vaccines: who are
they and where do they live? Pediatrics 2004;114(1):187–95.
[23] Charmaz K. Constructing grounded theory: a practical guide through qualitative analysis. Thousand Oaks, CA: Sage Publications; 2006.
[24] Maayan-Metzger A, Kedem-Friedrich P, Kuint J. To vaccinate or not to vaccinate
– that is the question: why are some mothers opposed to giving their infants
hepatitis B vaccine. Vaccine 2005;23:1941–8.
[25] Chen JY, Fox SA, Cantrell CH, Stockdale SE, Kagawa-Singer M. Health disparities
and prevention: racial/ethnic barriers to flu vaccinations. J Commun Health
2007;32(1):5–20.
[26] Lemstra M, Neudorf C, Opondo J, Toye J, Kurji A, Kunst A, et al. Disparity in
childhood immunizations. Paediatr Child Health 2007;12:847–52.
[27] Mixer RE, Jamrozik K, Newsom D. Ethnicity as a correlate of the uptake of the
first dose of mumps, measles and rubella vaccine. J Epidemiol Commun Health
2007;61:797–801.
[28] Ellickson RC. Order without law: how neighbors settle disputes. Cambridge,
MA: Harvard University Press; 1991.
[29] Merrill MH, Hollister AC, Gibbens SF, Haynes AW. Attitudes of Californians
toward poliomyelitis vaccination. Am J Public Health 1958;48(2):146–52.
[30] Streefland P, Chowdhury AMR, Ramos-Jimenez P. Patterns of vaccination acceptance. Soc Sci Med 1999;49:1705–16.
[31] May T, Silverman RD. Clustering of exemptions as a collective action treat to
herd immunity. Vaccine 2003;21:1048–51.
[32] Bardenheier B, Yusuf H, Schwartz B, Gust D, Barker L, Rodewald L. Are parental
vaccine safety concerns associated with receipt of measles-mumps-rubella,
diphtheria and tetanus toxoids with acellular pertussis or hepatitis b vaccines
by children. Arch Pediat Adol Med 2004;158:569–75.
[33] Brunson EK. The impact of social networks on parents’ vaccination decisions.
Pediatrics 2013, doi: 10.1542/peds.2012-2452 (published online: April 15).
[34] Bauch CT, Earn DJD. Vaccination and the theory of games. Proc Natl Acad Sci
USA 2004;101(36):13391–4.
[35] Bauch CT. Imitation dynamics predict vaccinating behavior. Proc Roy Soc B: Biol
Sci 2005;272:1669–75.
[36] Gangarosa EJ, Galazka AM, Wolfe CR, Phillips LM, Gangarosa RE, Miller E,
et al. Impact of anti-vaccine movements on pertussis control: the untold story.
Lancet 1998;351:356–61.
[37] Salmon DA, Haber M, Gangarosa EJ, Phillips L, Smith NJ, Chen RT. Health consequences of religious and philosophical exemptions from immunization laws:
individual and societal risk of measles. J Am Med Assoc 1999;282:47–53.
[38] Feikin DR, Lezotte DC, Hamman RF, Salmon DA, Chen RT, Hoffman RE. Individual and community risks of measles and pertussis associated with personal
exemptions to immunization. J Am Med Assoc 2000;284:3145–50.
[39] Jansen VAA, Stollenwerk N, Jensen HJ, Ramsay ME, Edmunds WJ, Rhodes
CJ. Measles outbreak in a population with declining vaccine uptake. Science
2003;301(5634):804.
[40] Salmon DA, Moulton LH, Omer SB, DeHart MP, Stokley S, Halsey NA. Factors
associated with refusal of childhood vaccines among parents of school-age
children: a case-control study. Arch Pediatr 2005;159:471–6.