DETERMINANTS OF MATERNAL TOLERANCE OF VACCINE-RELATED RISKS

In a time when informed consent requires knowledge of the risks and benefits of medical care and technology to be communicated to the public, perceptions of benefits and risks of these techniques and procedures take on special importance. The purpose of the present study was to examine the determinants of maternal tolerance of vaccine-related side-effects in their children. A questionnaire was sent to 226 mothers of young children in southwestern Ontario seeking their opinion of the benefits and risks of selected medical procedures. It asked them to identify the risk of serious reactions they would tolerate for a new vaccine with benefits similar to that of pertussis vaccine. The response rate to the questionnaire was 92%. This group of young, well-educated mothers had high regard for some of the most common procedures and treatments used in family practice. The less common and more invasive procedures (heart surgery, brain surgery) were viewed as carrying almost as much risk as benefit. Abortion was perceived as involving more risk than benefit. Levels of acceptable risk with respect to a hypothetical new childhood vaccine were determined. A risk level of 1 in 1 million was the most popular level of acceptable risk, chosen by 25% of the respondents. The next most frequently chosen risk level was 1 in 100 000, chosen by 22%. Tolerance of possible vaccine side-effects did not differ with maternal age, education or prior experience with adverse vaccine or drug reactions. A summary net benefit score was derived for four technologies commonly used in family practice (antibiotics, vaccinations, birth control pills and X-rays). Risk tolerance with respect to the hypothetical vaccine was not found to be statistically related to global perceptions of benefits and risks of these health care technologies as represented by the net benefit score. A proportion (13.7%) of respondents would decline the hypothetical vaccine if any risk at all was attached to its use. This group of people differed from the remainder of respondents in coming from families with lower income and in preferring risk statements to be made in non-numerical terms. It is suggested that there may exist a proportion of the population whose view towards prevention differ from the majority view and who deserve special attention.