Vaccine acceptance: How to build and maintain trust in immunization.

In Canada, over 80% of parents choose to vaccinate their children. Although this may appear positive, it is one of the lowest vaccination rates in the western world, and does not meet the 95% coverage rate needed to prevent outbreaks of vaccine-preventable diseases such as measles. A recent national immunization survey showed approximately 50% of parents are concerned about potential side-effects from vaccines, 25% believe that a vaccine can cause the disease it was meant to prevent, and 13% think alternative practices could eliminate the need for vaccines. In addition, vaccine hesitancy-defined by its determinants: confidence, complacency and convenience-is on rise. To address the complacency and trust (confidence) components of vaccine hesitancy, four best practices to optimize trust in vaccines and promote vaccine acceptance are presented. The first best practice is to understand the concerns; this is done at a population level via research and at individual level via motivational interviewing. The second best practice is to address these concerns by effectively presenting science-based information. This is done at a population level by communicating research and at an individual level by applying this research to the specific concerns, values and norms of the individual. Third, present immunization as a social norm, both in educational materials and in conversations. Finally, resilience is fostered by planning ahead (both at a population level and for individual practitioners) to manage events that can undermine trust and drive negative vaccine concerns, such as a new vaccine being added to the routine schedule or the emergence of an unexpected adverse event. Building and maintaining public trust in immunization takes time. Healthcare practitioners must keep in mind that while trust is a key element in vaccine acceptance, it is not the only element; convenience and access can also impact vaccine uptake. Nurturing trust is but one part of increasing vaccine acceptance and this brief will focus on strategies to build and nurture trust.

Taking the sting out of school-based immunizations.

Pain and fear widely contribute to negative experiences for students during school-based immunizations. In this preliminary research, we used a pre-existing network of 50 schools across Canada that participated in a biannual national immunization poster competition for grade 6 students organized by Immunize Canada to survey principals, teachers and students about their experiences with immunization pain and fear, how they want to learn about managing pain and fear and opportunities to include this information in the process of immunization. Responses revealed that both pain and fear are relevant to the immunization experience and that education and interventions are welcome by students and school staff. This may lead to improved attitudes about immunization, as well as future compliance with recommended immunizations.

La douleur et la peur contribuent largement aux expériences négatives des élèves lors de la vaccination scolaire. Dans le cadre de la présente recherche préliminaire, les auteurs ont recouru à un réseau déjà formé de 50 écoles du Canada qui avaient participé à un concours national bisannuel d'affiches sur la vaccination organisé par Immunisation Canada auprès d'élèves de sixième année. Ils ont sondé les directions d'école, les enseignants et les élèves au sujet de leurs expériences de douleur et de peur liées à la vaccination, de ce qu'ils veulent savoir sur la gestion de la douleur et de la peur ainsi que des possibilités d'intégrer l'information au processus de vaccination. Les réponses ont révélé que la douleur et la peur s'associent à l'expérience de vaccination et que les élèves et le personnel scolaire seraient heureux de recevoir de l'information et des interventions. Ces mesures pourraient améliorer les attitudes vis-à-vis de la vaccination et favoriser l'adhérence aux futurs vaccins.

Negligible colon cancer risk from food-borne acrylamide exposure in male F344 rats and nude (nu/nu) mice-bearing human colon tumor xenografts.

Acrylamide, a possible human carcinogen, is formed in certain carbohydrate-rich foods processed at high temperature. We evaluated if dietary acrylamide, at doses (0.5, 1.0 or 2.0 mg/kg diet) reflecting upper levels found in human foods, modulated colon tumorigenesis in two rodent models. Male F344 rats were randomized to receive diets without (control) or with acrylamide. 2-weeks later, rats in each group received two weekly subcutaneous injections of either azoxymethane (AOM) or saline, and were killed 20 weeks post-injections; colons were assessed for tumors. Male athymic nude (nu/nu) mice bearing HT-29 human colon adenocarcinoma cells-derived tumor xenografts received diets without (control) or with acrylamide; tumor growth was monitored and mice were killed 4 weeks later. In the F344 rat study, no tumors were found in the colons of the saline-injected rats. However, the colon tumor incidence was 54.2% and 66.7% in the control and the 2 mg/kg acrylamide-treated AOM-injected groups, respectively. While tumor multiplicity was similar across all diet groups, tumor size and burden were higher in the 2 mg/kg acrylamide group compared to the AOM control. These results suggest that acrylamide by itself is not a "complete carcinogen", but acts as a "co-carcinogen" by exacerbating the effects of AOM. The nude mouse study indicated no differences in the growth of human colon tumor xenografts between acrylamide-treated and control mice, suggesting that acrylamide does not aid in the progression of established tumors. Hence, food-borne acrylamide at levels comparable to those found in human foods is neither an independent carcinogen nor a tumor promoter in the colon. However, our results characterize a potential hazard of acrylamide as a colon co-carcinogen in association with known and possibly other environmental tumor initiators/promoters.

Dietary acrylamide does not increase colon aberrant crypt foci formation in male F344 rats.

Acrylamide, a known rodent and a probable human carcinogen, is spontaneously formed in foods cooked at high temperature. We studied the role of dietary acrylamide in modulating the early stages of colon carcinogenesis and assessed if dietary fat level was critical in altering the effects of acrylamide. Male F344 rats were subcutaneously injected with azoxymethane and were simultaneously randomized into 8 dietary groups (n=8 rats/group). Diets were based on AIN-93G semi-synthetic formula modified to contain either low fat (7% corn oil) or high fat (23.9% corn oil) and acrylamide at 0, 5, 10 or 50 mg/kg diet (wt/wt). All rats received the experimental diets ad libitum for 8 weeks, after which they were killed and their colons assessed for aberrant crypt foci (ACF), putative precancerous lesions. Irrespective of dietary fat level, rats with the highest tested dose of acrylamide (50 mg/kg diet) had significantly lower total ACF (p<0.05) and lower large ACF (those with 4 or more crypts/focus; p<0.001) compared with their respective controls (0 mg/kg diet). A significantly lower number of large ACF (p=0.046) was noted in rats treated with 10 mg/kg diet acrylamide exclusively in the high fat group, compared to the high fat control. This short-term bio-assay to test carcinogenicity of dietary acrylamide in the colon demonstrates that acrylamide, when administered through the diet at doses known to cause rat tumors, does not increase the risk of developing azoxymethane-induced precancerous lesions of the colon in rats. On the contrary, a high dose of dietary acrylamide decreased the growth of precancerous lesions in both low and high fat diet regimens in this model.