Prior to conducting the review, our study team defined its parameters:
i. Study scope: Our search focused on summarizing the barriers identified by immunization providers (including physicians, nurses, and pharmacists) toward implementing either provider-directed RR interventions (measures to deliver reminders to immunization providers) or patient-directed interventions (client interventions initiated by immunization providers). Methodologies to elicit provider views may include surveys, focus groups, or interviews.
ii. Search process: The systematic search retrieved articles using criteria developed based on input from the study team, keywords used in related previous reviews, and consultation with an information specialist.
iii. Quality assessment: Each paper was evaluated using an amalgamation of previous tools to assess the rigour of methodology and the quality of reporting.
iv. Barrier summary: We extracted the reported barriers and grouped them where possible, based on any noted commonalities.
Literature search and study selection
We searched MEDLINE, PubMed, EMBASE, Cumulative Index to Nursing and Allied Health Literature, Academic Search Premier, and PsychINFO for articles published in January 1990 through July 2011 on barriers to the use of immunization RR interventions, using various combinations of Medical Subject Headings terms (e.g., immunization, immunization programs, vaccination, appointment and schedules, reminder systems, parental notification) and keywords (e.g., recall, reminder, barrier, attitude, behavior, adopt). Search criteria were developed based on consultation with a library information specialist, as well as reviewing the keywords used in previous reviews of RR interventions. Full search criteria are described in Table
. Articles were considered eligible for evaluation if they were in English, contained original data, and described studies using quantitative and/or qualitative methodologies to identify the barriers perceived by immunization staff towards implementing RR interventions for childhood and/or adult immunizations. The perceived barriers could be towards any type of RR intervention for immunization directed at patients/their caregivers or healthcare providers. We excluded reviews, editorials, commentaries, and practice guidelines, as well as conference abstracts and other non-full text publications.
Literature search terms by database
We entered the titles of relevant articles into the PubMed “related articles” feature and also hand-searched the bibliographies of review papers, relevant articles, and systematic reviews from the Cochrane Database of Reviews of Effectiveness to identify additional pertinent papers. We used Google Scholar and Google to search the grey literature for government reports and other documents.
After duplicate articles were removed, all titles and abstracts were reviewed for relevance (Figure
). Those articles with abstracts pertaining to our main objectives were then reviewed in full-text. JP conducted the primary review; a second reviewer (SQ) was consulted to verify the final list of articles, as well as to confer on all articles for which there was uncertainty as to whether inclusion criteria were met. A consensus on each of these articles was reached.
This figure depicts the filter process for articles identified by our search strategies.
Methodological quality assessment
JP and SQ independently assessed the methodological rigour of all eligible articles based on a modification of tools designed to assess qualitative and quantitative studies (the Critical Appraisal Skills Programme (CASP) appraisal tool and Centre for Evidence-Based Management Survey Scoring System, respectively)
]. Articles were evaluated and classified as high/moderate/low quality based on the following 14 elements: clear research aims; appropriate research design; recruitment strategy; representativeness of population; avoidance of selection bias; data collection; sample size considerations; sufficient response rate; validity of measurements; ethical considerations; rigour of data analysis; significance testing; clarity of findings; and applicability of research. We scored one point for each element, for a maximum of 14; articles deemed to be of high methodological quality had ≥ 12 points, moderate = 8 – 11 points, and low = < 8 points. Rating disagreements were infrequent and were resolved through discussion.
A structured review form was then used by both reviewers to abstract data including country, study population, study methodology, and RR intervention(s) studied. The reviewers also independently abstracted any immunization providers’ perceived barriers towards the use of RR measures identified in each paper, and conferred to ensure consistency and completeness. Together, the reviewers then stratified these barriers where appropriate, based on commonalities.