Abstract
OBJECTIVES. Parents who have concerns about vaccine safety may be reluctant to have their children vaccinated. The purpose of this study was to explore how vaccination coverage among children 19 to 35 months of age is associated with health care providers' influence on parents' decision to vaccinate their children, and with parents' beliefs about vaccine safety.
METHODS. Parents of 7695 children 19 to 35 months of age sampled by the National Immunization Survey were administered the National Immunization Survey Parental Knowledge Module between the third quarter of 2001 and the fourth quarter of 2002. Health care providers were defined as a physician, nurse, or any other type of health care professional. Parents provided responses that summarized the degree to which they believed vaccines were safe, and the influence providers had on their decisions to vaccinate their children. Children were determined to be up-to-date if their vaccination providers reported administering ≥4 doses of diphtheria and tetanus toxoids and acellular pertussis vaccine, ≥3 doses of polio vaccine, ≥1 dose of measles-mumps-rubella vaccine, ≥3 doses of Haemophilus influenzae type b vaccine, and ≥3 doses of hepatitis B vaccine.
RESULTS. Of all of the parents, 5.7% thought that vaccines were not safe, and 21.5% said that their decision to vaccinate their children was not influenced by a health care provider. Compared with parents who responded that providers were not influential in their decision to vaccinate their children, parents who responded that providers were influential were twice as likely to respond that vaccines were safe for children. Among children whose parents believed that vaccines were not safe, those whose parents' decision to vaccinate was influenced by a health care provider had an estimated vaccination coverage rate that was significantly higher than the estimated coverage rate among children whose parents' decision was not influenced by a health care provider (74.4% vs 50.3%; estimated difference: 24.1%).
CONCLUSIONS. Health care providers have a positive influence on parents to vaccinate their children, including parents who believe that vaccinations are unsafe. Physicians, nurses, and other health care professionals should increase their efforts to build honest and respectful relationships with parents, especially when parents express concerns about vaccine safety or have misconceptions about the benefits and risks of vaccinations.
Most parents of young children in the United States have little or no familiarity with vaccine-preventable diseases because of the effectiveness of modern vaccines and the success of vaccination programs in disease prevention.1–3 Without direct experiences with vaccine-preventable diseases that occurred many years ago, parents may no longer be motivated by fear of these diseases to have their children immunized. Rather, parents may not vaccinate their children because of their concerns about vaccine safety, doubts about the effectiveness of vaccines, or misconceptions about vaccines. As new vaccines are added to the recommended immunization schedule, parents' concerns that may negatively influence their inclination to have the child vaccinated could become more prevalent. The objective of this study was to explore how vaccination coverage among children 19 to 35 months of age is associated with health care providers' influence on parents' decision to vaccinate their children and parents' beliefs about vaccine safety.
METHODS
Data collected between the third quarter of 2001 and the fourth quarter of 2002 by the National Immunization Survey (NIS) were analyzed. The NIS is a survey of US children 19 to 35 months of age conducted by the Centers for Disease Control and Prevention for the purpose of monitoring vaccination coverage rates in the 50 states, the District of Columbia, and 27 large metropolitan areas.
Data collection in the NIS occurs in 2 phases. In the first phase, a list-assisted random digit dialing (RDD) survey is conducted to identify households with children 19 to 35 months of age, to collect sociodemographic information about each age-eligible child in those households, and to obtain names and addresses of all of the vaccination providers who administered vaccine doses to the age-eligible children in those households. If the RDD respondent gives consent to contact the age-eligible children's vaccination providers, the second data collection phase is conducted. In the second phase, all of the vaccination providers named by the RDD respondent are contacted by mail to obtain the age-eligible child's provider-reported vaccination history. Provider-reported vaccination histories obtained from the second phase of data collection were used to evaluate the vaccination status of children sampled in the NIS. Smith et al4 provide a detailed description of the NIS and provide detailed descriptions of response rates for data analyzed in our study. The NIS was reviewed and approved by the institutional review board at the Centers for Disease Control and Prevention.
Vaccination Coverage
Because all of the children in our study were born in 1999 or later, we evaluated the vaccination status of children according to the 1999 recommended vaccination schedule.5 Sampled children were determined to be up-to-date (UTD) at the time of the NIS RDD interview if, by that time, their vaccination providers reported administering ≥4 doses of diphtheria and tetanus toxoids and acellular pertussis vaccine, ≥3 doses of polio vaccine, ≥1 dose of measles-mumps-rubella vaccine, ≥3 doses of Haemophilus influenzae type b vaccine, and ≥3 doses of hepatitis B vaccine.
Health Care Providers' Influence on Parents' Decisions to Vaccinate Their Children and Parents' Concerns About Vaccine Safety
Between the third quarter of 2001 and the fourth quarter of 2002, the NIS collected data on parents' knowledge and attitudes toward vaccinations using a series of questions called the Parent Knowledge Module (PKM). A random sample of parents who completed the NIS RDD interview and gave consent to contact their children's vaccination providers were administered questions from the PKM at the time of the RDD interview. Using data from the PKM, we defined health care providers as physicians, nurses, and other health care professionals. To evaluate the extent to which parents' decisions to vaccinate their children were influenced by each of those 3 health care provider types, parents were asked to express on a scale of 1 to 10 how much the provider type influenced their decision, where 1 meant “no influence” and 10 meant “extremely influential.” For our analysis, we interpreted a response of 1 to 5 as “not influential” and a response of 6 to 10 as “influential.” Parents whose decisions to vaccinate were not influenced by any of the 3 health care provider types were defined as not being influenced by health care providers. To evaluate parents' concerns about vaccine safety, parents were asked to express on a scale of 1 to 10 how safe they believed vaccines were for children, where 1 meant “not at all safe” and 10 meant “completely safe.” For our analysis, we interpreted a response of 1 to 5 as “not safe” and a response of 6 to 10 as “safe.”
Statistical Analyses
All of the estimates of vaccination coverage are reported along with the half-width of their associated 95% confidence interval (CI). To evaluate the statistical significance of the estimated differences in vaccination coverage rates and differences in other estimated percentages and means, we evaluated the 95% CI for the estimated difference. If the 95% CI did not include 0, we declared the difference to be statistically significant. To compare rates using the relative risk, we used log-linear models. All of the analyses were conducted using the statistical software package SUDAAN (Research Triangle Institute, Research Triangle Park, NC),6 which allows the sampling weights and the sampling design of the NIS to be taken into account in our statistical analyses.
RESULTS
In the study period between the third quarter of 2001 and the fourth quarter of 2002, 7695 children 19 to 35 months of age were sampled and contributed data to our study. During this study period, the estimated percentage of children who were UTD was 74.0% (95% CI: ±2.0%).
Association Among Parents' Beliefs About Vaccine Safety, the Influence of Health Care Providers, and Vaccination Coverage
During the study period, 2.0% (95% CI: ±0.5%) of parents believed that vaccines were not safe and were not influenced by a health care provider in their decision to vaccinate their children (Table 1). Compared with parents who responded that health care providers were not influential in their decision to vaccinate their children, parents who responded that their decision to vaccinate their children was influenced by a provider were twice as likely to respond that vaccines were safe for children, (9.5% vs 4.7%; relative risk: 2.01; 95% CI: 1.47–2.74). Among children whose parents believed that vaccines were not safe, those whose parents' decision to vaccinate was influenced by a health care provider had an estimated vaccination coverage rate that was significantly higher than among children whose parents' decision was not influenced by a health care provider (74.4% vs 50.3%; estimated difference: 24.1%; 95% CI: 9.3%–38.9%;Table 2). Parents who believed that vaccines were not safe were significantly less likely to be influenced by a health care provider in making a decision to vaccinate their children compared with parents who believed that vaccines were safe (20.7% vs 35.5%; estimated difference: 14.8%; 95% CI: 7.4%–22.2%).
Percentage Distribution According to Whether Parents Believed That Vaccines Were Safe and Whether Parents' Decisions to Vaccinate Their Children Were Influenced by a Health Care Provider
Estimated Vaccination Coverage According to Whether Parents Believed That Vaccines Were Safe and Whether Parents' Decisions to Vaccinate Their Children Were Influenced by a Health Care Provider
Association Among Sociodemographic Characteristics, Parents' Beliefs About Vaccine Safety, and Health Care Providers' Influence on Parents' Decisions
Children whose parents' decision to vaccinate was influenced by a health care provider or whose parents believed that vaccines were safe had demographic characteristics that were different from characteristics of children whose parents' were not influenced by a health care provider and who did not think that vaccines were safe for children (Table 3). Specifically, the estimated percentage of children whose parents' were not influenced by a health care provider and who did not think that vaccines were safe was significantly greater among children who had received no vaccine doses than among children who were UTD, significantly greater among non-Hispanic white children than among Hispanic children, significantly greater among children whose mother had 12 years of education than among children whose mother was a college graduate, and significantly greater among children living in a household with ≥4 children ≤18 years of age than among children living in a household with 1 child ≤18 years of age.
Distribution of Selected Sociodemographic Characteristics According to Whether Parents' Decisions to Vaccinate Their Children Are Not Influenced by a Health Care Provider and Whether Parents Believe That Vaccines Are Not Safe
DISCUSSION
Previous literature suggests that: (1) parents' perceptions about the dangers of vaccines is the most significant predictor that determines whether they do not intend to have their child vaccinated,7 and (2) that many parents have concerns about vaccine safety8 or hold important misconceptions about vaccines.9 Although parents seek information about vaccinations from many sources, they most commonly seek that information from a physician. 8,9As a result, physicians are in a position to influence many parents' decisions to vaccinate their children. In this era of low prevalence of childhood diseases because of the success of vaccines, parents have begun to question the necessity for and safety of vaccines.8 In a survey of pediatricians and family practitioners, the majority of respondents reported ≥1 parental vaccine refusal in their practice in the year preceding the survey.10 In another study, pediatricians who had faced vaccine refusals said that parents' concerns over safety were the major reason for refusal.11 A large percentage of physicians in that study responded that they would dismiss a family from their practice for refusing vaccines.
Parents' concerns about vaccine safety occur within the context of the communities in which their children live and may be shared by other parents in those communities.12 Unaddressed or ignored safety concerns may result in a community that has greater numbers of children who have received no vaccine doses13 or of children whose parents have claimed exemptions from laws that mandate childhood vaccinations by child care or school entry.14,15 Those children represent a pool of susceptible subjects who are at increased risk of acquiring a vaccine-preventable disease and then transmitting it to other children in the community.16
The ability to garner parents' trust has been cited as the key to influencing their decision to vaccinate their children.17–19 Trust in a health care provider is associated with use20 and delivery of preventive services.21 Distrust in a health care provider is associated with perceived barriers to immunization.22 Moreover, trust in the advice of a child's health care provider and feeling that it is easy to communicate with that provider have been found to be key factors associated with the parental belief that they had access to enough information to make a good decision about immunizing their child.18,19 Not having enough time has been cited by pediatricians as the greatest barrier to communicating with parents.17 By not spending time to adequately address parents' concerns or by extinguishing the trust of parents who express safety concerns by dismissing them from a practice, parents may divert their trust to homeopaths or practitioners of alternative medicine19,23 who may reinforce parents' misconceptions and fears and successfully discourage those parents from vaccinating their children.
Our study shows that there was a strong association between the influence that health care providers have on parents' decisions to vaccinate their children and vaccination coverage, even among parents who believed that vaccinations are not safe. In particular, children of parents who believed that immunizations are not safe had higher vaccination coverage if those parents reported that their decision to vaccinate their children was influenced by a health care provider. Our results showed that parents who believed that vaccines are not safe were significantly less likely to be influenced in their decisions to vaccinate their children compared with parents who believed that vaccines are safe. Understanding concerns of parents and developing trusting and positive relationships presents special challenges and opportunities for health care providers.
Many parents who express concerns about the safety of vaccines should not necessarily be characterized as being staunchly antivaccination. Rather, many parents who express concerns about vaccine safety have a perspective that is somewhere between a staunchly antivaccine outlook and an adamantly provaccine outlook.24 Health care providers are unlikely to influence skeptical parents to vaccinate their child by focusing exclusively on education about their children's risk of developing a vaccine-preventable disease. 7 By understanding the elements25,26 that constitute a trusting relationship and working toward earning parents' trust, health care providers may increase the likelihood of influencing those parents' decisions to vaccinate their children.
Guidelines for communicating with parents who refuse to vaccinate their children have been published.27 Those guidelines suggest that health care providers listen carefully and respectfully to parents' concerns, be knowledgeable about the risks and benefits about vaccines so that misinformation or misconceptions may be corrected, take steps to reduce the pain of injection and permit a schedule of immunization that minimizes the number of injections at a single visit, work with parents so that any financial barriers to vaccination are eliminated or minimized, and build a respectful relationship with parents so that the parents' decision not to vaccinate their children can be revisited. By building a trusting, respectful relationship, parents more likely may be influenced by the advice of health care providers.
Our study has several strengths. The results are based on data from a large national survey. Data from the survey can be used to monitor the number and percentage of children who may be susceptible to vaccine-preventable diseases because they are not vaccinated or are undervaccinated as a result of parental concerns over vaccine safety or because of the inability of health care providers to influence parents' decision to vaccinate their children.
One limitation of our work is that parents' concerns about vaccine safety and the reported influence of providers on parents' decisions to vaccinate their children were not measured continuously over the period during which children are administered vaccines. Therefore, our data cannot show whether parents' attitudes and beliefs can be modified over time to positively influence the vaccination status of their children. A further potential limitation of our work is the 28% response rate of the NIS. Because of the potential for selection bias resulting from the low response rate of the NIS, our estimates of vaccination coverage and parents' beliefs may not accurately represent that of the entire target population of children 19 to 35 months of age in the United States. Although weighting adjustments4 were used to mitigate the potential for selection bias resulting from low response rates, the effectiveness of those adjustments is unknown. However, we believe that the directions of the associations that we reported among parents' concerns over vaccine safety, influence of health care providers on parents' decisions to vaccinate their children, and the vaccination status of children are credible.
CONCLUSIONS
We are encouraged by our finding of a strong association between the influence of health care providers on parents' decisions to vaccinate their children and vaccination coverage, particularly among parents who believe that vaccinations are not safe. We show that parents may be influenced positively by their health care providers. A probable prerequisite for influence is a trusting and respectful relationship. In this era of low incidence of childhood diseases and increased concerns about vaccine safety, physicians, nurses, and other health care professionals play a central role in maintaining confidence and trust in childhood immunizations and in achieving high vaccination coverage rates.
Footnotes
- Accepted June 7, 2006.
- Address correspondence to Philip J. Smith, PhD, Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases, MS E-32, 1600 Clifton Rd, NE, Atlanta, GA 30333. E-mail: pzs6{at}cdc.gov
The authors have indicated they have no financial relationships relevant to this article to disclose.
REFERENCES
- Copyright © 2006 by the American Academy of Pediatrics
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