Barriers to Immunization and Missed Opportunities

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Abstract
The articles prior to January 2008 are part of the back file collection and are not available with a current paid subscription. To access the article, you may purchase it or purchase the complete back file collection here Jeanne M Santoli, MD, MPH; Peter G SziIagyi, MD, MPH; Lance E Rodewald, MD The incidence of vaccine-preventable diseases is at an all time low, and preschool immunization coverage levels are at an all time high. This is in marked contrast to the situation 9 years ago when there was a measles resurgence due, in part, to low preschool vaccination rates. In 1991, surveys conducted in several US cities revealed immunization rates as low as 10-42% among children aged 24 months.1 One of the goals established by Healthy People 2000 is 90% immunization coverage for 2year-olds by this year,2 but the recent findings of a 77% coverage rate in this age group3 suggest that we are not there yet. Achieving high coverage rates requires an understanding of the barriers to childhood immunization. A great deal of research regarding these barriers has been conducted since the measles resurgence. The purpose of this review is to summarize findings of that research (Table 1). We will first examine several factors that, although mentioned frequently as barriers to timely receipt of immunizations, have not held up in the literature. Second, we will review a number of factors consistently supported by strong evidence to be associated with underimmunization. FACTORS WHOSE ASSOCIATION WITH UNDERIMMUNIZATION IS NOT SUPPORTED BY STRONG EVIDENCE Parental attitudes The first factor, parental attitudes, includes health beliefs about tlie safety and efficacy of vaccines, the severity of vaccine-preventable diseases, and the priority parents place upon immunizing their children. It was commonly believed, and research supported the idea, that poor parent attitudes prevented children from being vaccinated. One frequently-cited Utah study, for example, demonstrated an association between pertussis immunization and accurate parent knowledge about vaccines and illness.4 Health care providers were among those who believed that parent attitudes and knowledge were largely responsible for low immunization rates among their patients. In one community-wide survey of pediatricians and family practitioners in Ohio, more than 95% of those surveyed reported parental forgetfulness and not knowing when immunizations are due as barriers to immunization.5 While such studies certainly suggest that parental knowledge plays a role in immunization, they do not specifically address parental health beliefs or attitudes. Several investigators have conducted studies designed to focus upon this relationship between immunization coverage rates and parental beliefs and attitudes. These investigators have found no differences in maternal health beliefs (including perceived severity, susceptibility, benefit, and cost; health motivation; and locus of control) between infants who are up to date and those who are not.6,7 Using a community-based approach in inner-city Baltimore, with children living in poverty, another group of investigators found a disappointingly low immunization coverage rate of 54% at 24 months of age, despite the fact that 86% of parents believed shots were effective and 71% believed that children were vulnerable if not up to date.8 Similar results have been demonstrated in more affluent populations as well.9 Substantial evidence, it seems, fails to support an association between parental attitudes toward vaccination and immunization status - parents want their children protected by vaccination. One final issue relevant to parental attitudes about immunization is worth mentioning. That issue involves a group of parents with religious or philosophical objections to childhood immunizations. Certain religions forbid vaccination, and almost all states recognize this by allowing religious exemption from school-entry vaccination laws. In addition, some states allow exemption from vaccination for philosophical reasons - ie, the parents do not have a religious contraindication to vaccination, but they are philosophically opposed to vaccination. The decision by a parent to exempt his/her child from vaccination should not be taken lightly, even though the proportion of parents taking philosophical exemption appears to be less than two percent (given the 98%… 10.3928/0090-4481-19980601-11