Parental Vaccine Safety Concerns in 2009

DISCUSSION

Among the most important findings from our study is that almost 1 (12%) in every 8 parents has refused at least 1 vaccine recommended by their children's physician. The reasons for these refusals were often vaccine specific; parents may have more concerns regarding 1 vaccine than another. Newer vaccines (varicella, meningococcal conjugate, and HPV) were more likely to be refused than older vaccines (MMR), despite safety concerns expressed by many parents regarding vaccination in general. Parents also had varying perspectives on the effectiveness of individual vaccines and the diseases that they were targeted to prevent.

One current specific immunization safety concern has been the spurious association of vaccines with autism. Although peer-reviewed original scientific research and multiple expert committees that have reviewed all available data on this issue have failed to show any association between vaccines and autism, anecdotally the concern continues to affect parents.⁸ Our study indicates that a disturbingly high proportion of parents, >1 in 5, continue to believe that some vaccines cause autism in otherwise healthy children. This finding indicates that current public health education campaigns on this issue have not been effective in allaying the concerns of many parents. Officials must attempt to develop more effective and targeted education campaigns that focus directly on this issue if their goal is to match parents' level of concern with the available scientific evidence. Recently, the use of newer social marketing techniques have been suggested as potential strategies to address vaccine safety concerns.^9,10

Overall, parents in our study overwhelmingly shared the belief that vaccines are a good way to protect their children from disease (90%) and do what their doctor recommends regarding the provision of vaccines for their children (88%); however, many of these same parents did express concerns regarding the potential adverse effects of immunizing their child and especially seemed to question the safety of newer, as compared with older, vaccines. Importantly, parents have the right and responsibility to be adequately informed of any procedure, medication, or vaccine that is administered to their child. It is also the responsibility of health care providers to be informed of the evidence base to address fully any parental concerns.

It is likely that parents would benefit from educational programs that highlight the manner in which safety assessments are conducted before the licensure and subsequent recommendation of new vaccines. In general, studies have shown that parents who believe that they personally have a lack of knowledge regarding vaccines are more likely to have negative attitudes regarding immunization.¹¹ It is likely that physicians also would benefit from such information in their efforts to discuss vaccine safety with the parents of their patients. This is especially important, because our data clearly support the notion that physicians are a frequent and well-trusted source of immunization information.

Similar to previous studies,^1,12 we found variation among parents in their beliefs regarding vaccines. For example, our study found gender differences with regard to vaccine safety concerns. Women were more likely than men to be concerned about the potential for serious adverse effects from vaccines. They were also more likely to believe that some vaccines cause autism in healthy children and to have ever refused a vaccine for their child. These differences may be helpful to those who develop educational materials for parents and for physicians to tailor their messages to match the concerns of the parents whom they see in their practices.

Whereas others have reported variation in immunization refusal among religious groups,¹³ we found significant differences according to race/ethnicity of our respondents. Hispanic individuals were more likely than white or black individuals to believe that some vaccines cause autism in healthy children. This is consistent with the findings of Shui et al,¹⁴ who found Hispanic individuals to have a higher rate of negative attitudes toward immunization than white individuals. Because Hispanic individuals are now the largest and the fasting growing minority population in the United States, our findings are especially important to guide future educational efforts to this community. Such efforts are necessary to address what could be a growing concern that may have a significant impact on immunization rates, both in specific geographic areas and nationwide.

It is somewhat reassuring that we also found that Hispanic individuals currently have the lowest rate of vaccine refusals compared with black and white individuals. This may be indicative of a lag between perception regarding vaccine safety and action. Another possibility is that safety concerns may currently be outweighed by the societal pressure within this community to vaccinate their children; however, addressing this concern explicitly before it has an impact on immunization rates should be strongly considered by both public health officials and private providers in these communities.

In contrast to previous studies^1,15 that found varicella to be the vaccine most likely to be refused by parents, our results demonstrated HPV in that position with varicella and meningococcal conjugate refused at roughly similar rates. The previous studies did not include HPV and meningococcal conjugate vaccines because they were not licensed and recommended at the time that the studies were conducted. Our findings also indicated a smaller proportion of parents refusing the MMR and varicella vaccines than found by Gust et al.¹ Our results are likely a reflection of parental response to these newer, less trusted vaccines and the complex issues surrounding their provision, especially HPV.

This study has certain limitations. There is the potential for selection bias in our sampling. Recruitment to the study panel was limited to those who could be reached through random-digit dialing. This would exclude US households without telephones and potentially those who use software to block calls from unknown numbers. As a self-administered survey, it is subject to response bias. The investigators attempted to minimize this bias as it relates to immunization practices and attitudes by inviting panel members to participate with a description of the survey that did not mention specific topics and by including the vaccination questions among questions on other, unrelated topics. Findings in this study that are comparable to previous studies suggest that this study was not more affected by response bias than similar surveys in the past. Although sensitive questions about attitudes and practices were asked, the respondents knew that their identities would be protected and therefore had maximal likelihood of answering truthfully.