Predicting parents' decisions on MMR immunisation: a mixed method investigation.

Background: Increasing uptake rates for MMR vaccination requires an understanding of factors leading parents to decide for and against vaccination, particularly in the light of recent developments.

Objective: We investigated factors relevant to immunising and non-immunising parents and the extent to which these factors predicted their decisions.

Methods: The study was conducted in Edinburgh, UK. A two-stage mixed method design was used. Delphi technique elicited parents' views of factors relevant to MMR immunisation. Twenty-six factors identified as relevant were incorporated into a final questionnaire. Using cluster sampling, the final questionnaire was distributed to parents recruited through a group of local nurseries. 110 parents participated: eighty (72.7%) had had their child MMR vaccinated, thirty (27.3%) had refused the vaccine. The factors in the final questionnaire were analysed against vaccination status using a direct binary logistic regression model.

Results: Four factors significantly predicted vaccination status, (prediction toward 'yes vaccination'). These were the influence of current research (OR=0.18, 95% CI=0.07-0.51), the helpfulness of leaflets and information packs (OR=3.27, 95% CI=1.38-7.75), the importance of eradication of rubella (OR=2.42, 95% CI=1.01-5.78), and the importance attached to the risk of adverse reactions (OR=0.65, 95% CI=0.48-0.87).

Conclusions: Differences between immunising and non-immunising parents lie in the importance attached to four relevant factors. Excluding risk of adverse reactions, these factors have not been previously identified as salient and require to be explored further. Health advice to parents should highlight the identified importance attached to eradicating rubella and explicitly reflect research findings.