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Strategies to improve vaccination uptake in Australia, a systematic review of types and effectiveness

Strategies to improve vaccination uptake in Australia, a systematic review of types and... H igh vaccination coverage remains crucial to reduce individual disease risk and to develop and maintain population‐based (herd) immunity. For Australian infants aged 12 and 24 months, coverage for nationally funded vaccines exceeds the countrywide target of 90%. However, coverage for such vaccines in adolescents and children aged 4 and over fails to meet this target. Uptake of nationally funded seasonal influenza vaccine is estimated at 75% for adults aged 65 years and over, which is higher than uptake of the 23‐valent pneumococcal polysaccharide vaccine (54%) funded nationally for the same group. For the same vaccines in Aboriginal and Torres Strait Islander peoples aged 15 years and over, uptake is less than half of this. Certain populations remain at higher risk for under‐immunisation, including Aboriginal and Torres Strait Islander people and others experiencing deprivation or social exclusion. Similarly, certain medically, behaviourally and occupationally at‐risk groups are at greater risk of vaccine preventable diseases (VPDs), thus enhancing the importance of vaccination in these groups. A review of international evidence for interventions to improve vaccination uptake highlighted that multi‐component strategies had positive effects on adults and children. However, some of these strategies alone had less convincing evidence of effectiveness. This review included only a minority of Australian studies, all conducted prior to 2000. Other international reviews have included studies from Australia but focus only on specific strategies and/or target groups. The evidence for strategies to improve vaccination uptake identified in international reviews may have reduced relevance given some unique aspects of Australia's national immunisation program (NIP). This systematic review aims to profile and critique available evidence of strategies to improve vaccination uptake in Australia and evaluate their effectiveness. Methods The relevant literature was identified, classified and critiqued as follows. This is summarised in Figure 1 . 1 Search strategy and review process based on PRISMA a statement. Search strategy Peer‐reviewed literature was identified by searches conducted in electronic bibliographic databases by a medical librarian, the third author. Databases included OVID Medline (1948 to April Week 2, 2011), OVID EMBASE (1980 to Week 16, 2011), OVID PsycINFO (1987 to April Week 3, 2011), Informit databases (Health subset), and CINAHL via EBSCO (1982–2011). A combination of database‐specific controlled vocabulary and general free text terms were used. The main controlled vocabulary terms were ‘immunisation’, ‘immunisation programs’, ‘vaccines’ as well as terms for individual VPDs and associated vaccines. Controlled vocabulary terms for other key concepts associated with strategies to improve uptake were also searched and combined with the immunisation, vaccines and disease terms. Free text terms representing all major concepts were also used in combination with the controlled vocabulary terms to maximise retrieval. This search strategy was applied from early 1997, when the formal Immunise Australia program was established, through to May 2011. Results were limited to humans and English language. Reference lists of all identified literature were scanned to locate additional items. A copy of the search strategy is available from the authors upon request. Grey literature (material not published in peer‐reviewed sources) was identified through hand searching all Public Health Association of Australia (PHAA) National Immunisation Conference abstracts from 1998 to 2010, scanning state/territory health department and state‐based general practice network websites as well as consulting with experts in the field. Copies of potentially relevant conference posters and/or presentations were requested from primary authors. In addition, the Australian Digital Theses Program database, the National Library of Australia's Trove database and the Australian Resource Centre for Healthcare Innovations (ARCHI) were searched systematically using the controlled vocabulary terms described above. Eligibility criteria, classification of studies and data extraction To be included, studies must have reported original research about, or evaluation of, one or more interventions to improve uptake of one or more vaccines available in Australia. They must have included a quantitative measure of uptake as a primary outcome with studies describing uptake in the absence of an intervention or reporting only other outcomes (i.e. descriptive or qualitative) excluded. Also excluded were evaluations of the introduction of vaccines onto the Australian Government funded NIP and routine implementation of school‐based vaccination programs as these were considered baseline practice in Australia. The title and abstract of all studies were screened according to the inclusion criteria. The first two authors undertook this independently with discrepancies resolved by discussion with the third author. A data extraction form was developed and pilot tested on five randomly selected studies, and refined accordingly. The first two authors independently extracted relevant information from each study. Study design was classified according to Irwig & Cumming study types in population health research. Interventions in identified studies were classified into four categories, as defined by The Task Force on Community Preventive Services and ten major target groups, based on those in the Australian Immunisation Handbook 9 th Edition. Critique of published studies In light of considerable heterogeneity in study design, a combination of two validated and recommended tools for assessing quality in public health interventions were combined and applied to studies published in the peer‐reviewed literature. The tool assessed reporting quality, sampling, measurement, data analysis, interpretation of results and study design. The first two authors independently assessed studies using the modified quality scale then met to discuss and gain consensus on the final quality rating (1=weak, 2=moderate, 3=strong). One article with a potential conflict of interest was assessed by an independent reviewer and the first author. Assessing the quality of grey literature was not feasible due to substantial differences in reporting format and the limited information available in these sources. Synthesis of results The primary outcome was a change in vaccination uptake in the specified target group. Reporting of the principal results is based on the PRISMA statement. Table 1 combines included studies by intervention type and target group. 1 Target groups and intervention types reported by first author (publication year) of included study (n=49). Newborns Children Adolescents Adults Elderly Aboriginal and Torres Strait Islander peoples Pregnant women Medically at risk a Behaviourally at risk b Occupationally at risk c TOTAL Increase community demand Banks (2008) Bartu (2006) Hawe (1998) Kirby (2010) Tomney (2010) Van Buynder (2010) Skinner (2000) Juraskova (2011) Byrnes (2006) Puech (1998) Wallace (2008) d Thomas (2008) Wallace (2008) d Ferguson (2010) Lennox (2007) Devine (2007) Ballestas (2009) Waddington‐ Powell (2008) Scott (2010) Fullerton (2010) De Alwis (2010) e 20 Enhance access Bond (1998) Ressler (2008) Brown (2010) Elia (2010) f Smith (2010) Gill (2010) g Reeve (2008) Elia (2010) f Gill (2010) g Elia (2010) f Gill (2010) g Elia (2010) f Gill (2010) g Grant (2005) Piper (2008) Gold (2000) SESIAHS (2008) Fredricks (2010) McDonald (2007) Rogers (2005) Howe (2009) Elia (2010) f De Alwis (2010) e 16 Provider based interventions Ali (2009) Frank (2004) Finlay (2008) Kerse (1999) McIntyre (2003) Irwin (2002) Lake (2008) Colgrave (2010) De Alwis (2010) e 9 Regulatory interventions Connors (1998) Lam (1998) Bond (2002) Smithers (2003) Stewart (2002) Helms (2011) 6 TOTAL 2 14 4 4 8 4 0 6 3 12 Column Total: 51 h Row total: 57 i a. Those whose current or past health status places them at increased risk of acquiring a vaccine preventable disease, excluding pregnant women (tabled separately). b. Those whose engage in risk taking behaviour which places them at increased risk of acquiring a vaccine preventable disease. c. Those who engage in an occupation which places them at increased risk of acquiring a vaccine preventable disease and thus they have specific vaccination recommendations. In this review, these groups include health care workers and Australian Defence Force personnel. d. Wallace (2008) listed in 2 cells as strategy targeted both Aboriginal and Torres Strait Islander peoples & elderly. e. De Alwis (2010) listed in 3 cells as it covers multiple intervention types. f. Elia (2010) listed in 5 cells as strategy targets the entire age spectrum and health care workers. g. Gill (2010) listed in 4 cells as targets entire age spectrum. h. Three articles are listed more than once under an intervention type, however are only counted once the row total. i. One article is listed more than once under a target group, however is only counted once the column total. Results The initial search identified 1,576 articles after removing duplicates with 49 articles meeting the inclusion criteria ( Figure 1 ). Complete posters and/or oral presentations were requested from 23 authors of PHAA conference abstracts with 18 supplying material for consideration. Among the 49 included articles, 32 (65%) were published in peer‐reviewed journals, 14 (29%) were conference abstracts or presentations and three (6%) were reports. There was an average of two to three studies published per year from 1997–2007 with more than half published from 2008 onwards (n=28). Studies were conducted across all Australian states and territories, although more than half (n=31) were from New South Wales and Victoria. A summary of the key attributes of included studies is available online at http://www.ncirs.edu.au . Of the 49 included studies, 37 (76%) were concluded to be successful or effective; nine (18%) were unsuccessful or had a lower‐than‐expected increase in coverage; and three (6%) studies were unable to determine effectiveness of their intervention. Intervention types The four intervention categories included: those which increase the community's knowledge or awareness about vaccination (increase community demand, n=20); those which reduce the cost, or increase convenience, of accessing vaccination services (enhance access to vaccination, n=16); those aimed at vaccine service providers (provider‐based interventions, n=9); and those which establish guidelines, policies or regulations to increase compliance or mandate vaccination (regulatory interventions, n=6). In the categories of increasing community demand and provider‐based interventions, the most effective and common strategies were patient reminder/recalls and provider reminders. Education for the public and providers (either alone or as part of a multi‐component strategy) had variable impact on uptake, with increases less substantial or direct when compared with reminder/recalls. Also effective were integration of vaccination status checks into routine health assessments, individual provider support, and targeted promotion campaigns in the mass media, although studies of these interventions were minimal and confined to particular target groups and vaccines. For enhancing access, catch‐up plans for those overdue for vaccination were particularly effective, often reducing the percentage of those overdue by more then 50%. The two studies involving an accelerated vaccination schedule for hepatitis B showed an increase in the overall completion rate compared with the standard schedule. Results from the few studies of home visits for routine childhood vaccination highlighted their effectiveness, particularly when targeting Aboriginal and Torres Strait Islander children. The same effectiveness was observed for expanding access in hospitals and vaccination clinics in public settings. There were several effective regulatory interventions that were beyond ‘baseline practice’ of funding vaccines on the NIP and school‐based vaccination programs. These included national parental incentives; the maternity immunisation allowance (MIA) and linking vaccination to the child care benefit as well as a jurisdictional hepatitis B vaccination policy for high‐risk infants then subsequently for all newborns. All other regulatory interventions primarily focused on provision of funded vaccine coupled with mandatory vaccination policies for health care workers (HCWs) and were implemented at a jurisdictional and/or organisational level. The small number of studies showed limited effectiveness of this strategy. Target groups and vaccines Children were the most commonly targeted group (n=14) and pregnant women were the least targeted (n=0); see Table 1 . The most commonly targeted vaccines were those for influenza (H1N1 pandemic and seasonal influenza, n=21), followed by hepatitis B vaccine alone (n=13), then any combination of vaccines included on the NIP for children under seven years of age and/ or for Aboriginal or Torres Strait Islander peoples (n=11). Study design Major categories of study designs included ‘descriptive’ (n=22), ‘before/after’ (n=12), and ‘analytical’ (n=15). A higher proportion of studies reported in grey literature had descriptive (65%, 11/17), and ‘before/after’ designs (35%, 6/17) compared with published studies (34%, 11/32 and 19%, 6/32). The 15 analytical studies, which addressed questions of causality were all published in the peer‐reviewed literature. Nine were randomised controlled trials (RCTs) with the remainder cross‐sectional and cohort studies and a quasi‐RCT. Outcome indicators Of the 49 included studies, 29 collected baseline uptake for comparison. Differences in uptake before and after interventions varied vastly. Two studies reported large differences (>40%) following catch‐up programs in at‐risk populations, the highest of any studies. Three studies reported moderate differences (21–40%) following a number of interventions including: routine reminder letters for NIP vaccines for four‐year‐olds; a multi‐component promotion and education program for HCW influenza vaccination; and the introduction of a neonatal hepatitis B vaccination policy for medically at‐risk infants. The majority of studies with baseline uptake (n=15) reported a small difference post‐intervention (1–20%). Among studies with baseline data, only one reported no improvement in uptake which was observed three months after the introduction of a new vaccination policy for HCWs in one hospital. The remaining nine studies mentioned baseline uptake only, without specifying any comparative increase following the intervention. Two studies used the number of vaccines ordered as an indicator of vaccine uptake. These demonstrated satisfactory increases in vaccine ordering following an educational campaign and jurisdictionally centralised provision of free hepatitis B vaccine to those newly diagnosed with hepatitis C. However, this method could only act as a proxy for estimating uptake as the amount of wastage could not be accurately measured. Quality of included studies published in peer‐reviewed literature Only studies reported in the peer‐reviewed literature (n=32) were assessed using recommended tools (see Methods). Overall, most studies scored high (n=18) to moderate (n=10) for quality. In general, studies scoring highly used analytical designs (excluding quasi‐RCTs), described interventions thoroughly, utilised appropriate data analysis methods, and provided reasonable and meaningful interpretations of the results. Studies with a low quality score were less geared towards measuring change in a rigorous manner. Their deficiencies were mainly poor description of data collection and analysis methods as well as unclear outcome indicators, thus reflecting potential measurement biases. Generally, all studies had relevant and detailed descriptions of the intervention, sample size and target group. Discussion This review found 49 studies reported since 1997 that evaluated interventions to improve vaccination uptake in Australia. There was considerable heterogeneity in interventions, target groups, settings and study designs. Hence, for any one intervention there is only a small amount of evidence available which is itself of variable quality. In this context, most strategies reviewed had some impact on increasing vaccine uptake with only one ineffective strategy reported. Catch‐up plans demonstrated the greatest impact on uptake yet recall/reminders for patients and provider reminders were the most commonly‐evaluated strategies and had the highest level of evidence, each with two RCTs demonstrating their effectiveness. No single study evaluated the effects of different types of patient reminder/recalls, although this has been done internationally to show that all types are effective, telephone calls more so than others. There was no evidence for the effectiveness of new technologies (e.g. text messages, smart phone ‘apps’) for recall/reminders. There is an urgent need for these methods to be evaluated in the light of the proven effectiveness of reminders in general. There was some evidence of the effectiveness of several individual strategies to increase community demand for vaccination. Promising results are seen with integrating vaccination status checks into routine health assessments for prisoners and those with intellectual disabilities. This strategy should also be evaluated in other population groups targeted for routine health assessments. Despite measurement limitations, evidence was positive for the use of mass media campaigns to increase community demand for nationally recommended and/or funded vaccines in certain target groups. This is supported by an earlier Australian study, however international evidence is insufficient to support the use of this strategy. Only one included study evaluated education for a specific community in isolation. In all others, education was included as part of a multi‐component intervention which makes it challenging to detect the effectiveness of this strategy on its own. This, along with the need for a longer intervention period to observe the translation of knowledge to behaviour change, explains why this and other international reviews have found insufficient evidence to demonstrate the effectiveness of any form of education in increasing uptake. Reminders and education/support for providers were effective and widely used particularly in relation to at‐risk patients. In contrast, international evidence is mixed on the effectiveness of provider education alone, yet its use in combination with other provider‐based strategies is recommended. International evidence also recommends standing orders and provider audit and feedback, although this review identified insufficient evidence to draw any strong conclusions about the effectiveness of these strategies in the Australian context. International debate around the effectiveness of provider incentives remains unresolved. Despite the availability of ecologic evidence of their effectiveness in Australia, no studies of this strategy were eligible for inclusion in this review. Most of the evidence for strategies to enhance access to vaccines was in at‐risk groups. As has been demonstrated internationally, an accelerated hepatitis B schedule improved uptake in injecting drug users, however there was no evidence of the effectiveness of accelerated schedules for other multi‐dose vaccines. Home visits for routine childhood immunisation were particularly effective in Aboriginal and Torres Strait Islander communities, in contrast to mixed international evidence of the effectiveness of this strategy across the age spectrum. Expanding access in hospital settings as a single intervention was effective when targeting medically and occupationally at‐risk groups, which is in contrast to international evidence. The effectiveness of reducing out‐of‐pocket costs for vaccination in increasing uptake is well established. This strategy is particularly effective in those experiencing financial deprivation, yet has reduced effectiveness where public perception about the disease or vaccine is vexed (e.g. influenza). Inherent in all included studies was the provision of free vaccine under the NIP, hence this strategy was not specifically evaluated. This should be taken into consideration when interpreting the results and comparing these to evidence from other countries where payment for the vaccine is often required. As has been observed in similar systematic reviews, studies of regulatory interventions were limited. This may be a result of the exclusion of studies evaluating the introduction and funding of vaccines under Australia's NIP, which has an established body of evidence demonstrating its effectiveness. One included study provided good evidence of the effectiveness for legislated parental incentives for maintaining up‐to‐date vaccination of their children, which is also supported by another Australian study, although international evidence to support this strategy remains insufficient. There is good international evidence that linking immunisation to school or childcare entry is effective, although no identified studies formally evaluated this in the Australian context. As numerous strategies may be implemented in addition to regulatory interventions during the evaluation period, it is difficult to measure the sole impact of these interventions on vaccine uptake. The use of two or more strategies in combination appears to be an effective approach for improving vaccination uptake in Australia. Most commonly, multi‐component strategies focus on increasing community demand for, and enhancing access to, vaccination. Provider‐based strategies are occasionally incorporated and regulatory interventions usually underpin these and are evaluated in isolation. Results from international reviews overwhelmingly support the use of multi‐component strategies to increase coverage for children and at‐risk groups. There was a lack of evidence for strategies to improve vaccination uptake in particular ‘at‐risk’ groups. No included studies focused on pregnant women, possibly as they are a relatively new target group for routine vaccination. Also limited was evidence of strategies to increase vaccine uptake in behaviourally at‐risk groups such as prisoners and injecting drug users. A more concerted effort to measure uptake in these groups is needed. Notably, there were a small number of strategies targeting Aboriginal and Torres Strait Islander peoples who suffer higher rates of VPDs. This may be the result of a reporting deficiency, as it is known that many strategies are being implemented in this target group. Action to collate, review and selectively evaluate strategies to increase vaccine uptake in this group is urgently needed. A major limitation of included studies was their design and outcome measurement. In many studies it was not possible to sufficiently determine the impact of the intervention because of a lack of baseline measurement or a control group. In addition, outcome indicators were frequently poorly defined and were not uniform across studies, thus limiting comparison. Although the majority of studies reported some increase in uptake, less than half quantified the relationship between this and the study factors. Future evaluations should aim to use appropriate and valid measurement methods, compare results to baseline or existing coverage estimates, and acknowledge contextual factors which may influence findings. Only one study utilised behaviour change theory. Interventions which include a behavioural change component can be enhanced by applying a clearly articulated theory which is backed by evidence of its effectiveness on behaviour. This will allow the identification of variables thought to cause change in behaviour, and facilitate the accumulation of evidence of effectiveness across different contexts, populations and behaviours, as well as assist in the understanding of the mechanisms of change. Staff employed to implement immunisation programs conducted many included studies in‐house, often with limited capacity or resources to undertake scientifically rigorous evaluations. This is a common occurrence in the evaluation of public health interventions, although without close ties between evaluation and program implementation there is a risk of wasting resources on ineffective or even counter‐productive programs. Evaluating existing strategies to improve vaccination uptake in Australia and disseminating the findings through more publicly‐accessible mechanisms should be encouraged. In doing so, a recommended framework, such as the TREND statement (available at http://www.cdc.gov/trendstatement/docs/TREND_Checklist.pdf ) should be applied to enhance utility and transparency. The value of including data from different types of studies in systematic reviews of health interventions is being increasingly recognised, although it comes with known theoretical and practical challenges. In this review, grouping ‘similar’ interventions (i.e. reminder/recall) and considering these as a collective body of evidence may have disguised important differences between individual interventions and limited full consideration of the contextual factors which would undoubtedly impact on effectiveness. However, efforts were made to tabulate the context of interventions so comparisons could be made. Aspects of the review process, such as the categorisation of studies and quality assessment, were potentially open to reviewer bias. However, the use of established frameworks defining intervention type and study design, independent assessment and third party verification all assisted in reducing the impact of this potential bias. A rigorous process was used to combine two validated quality assessment tools which led to the development of a new tool. The final tool allowed for a more extensive assessment of study quality than the two original tools individually, although it was not specifically validated. Publication bias and partiality in the location of studies was not felt to be a major limitation in this review as multiple bibliographic databases were searched, numerous experts were consulted and grey literature was extensively searched and included. However, it is notable that null findings were more frequently reported in peer‐reviewed rather than grey literature. Excluding studies that could not demonstrate the impact of a particular strategy on vaccine uptake may have reduced the extensiveness of reporting of known strategies. Conclusion Despite the limitations in the quality and quantity of included studies, available evidence highlighted some potentially effective strategies to improve vaccination uptake in Australia. In contrast to the system‐wide demand for their use, activities to increase vaccination uptake are infrequently and often inadequately evaluated. There remains an elusive pool of unpublished evidence about how to improve vaccination uptake; barriers to obtaining and disseminating this information need to be identified and overcome. In addition, new, widely used and/or potentially effective strategies with limited evidence need to be identified and appropriately evaluated using the most practical and scientifically rigorous designs within the resources available. In a climate where funding and resources are finite, the development of such an evidence base is essential to avoid the continued use of ineffective interventions. It is hoped that those desiring to improve the performance of vaccination programs can use this base of evidence in conjunction with that from overseas to inform and guide their efforts. In addition, areas for future investigation of strategies to raise and sustain vaccination uptake can also be guided by the results of this review. Acknowledgements The National Centre for Immunisation Research and Surveillance is supported by the Australian Government Department of Health and Ageing, the NSW Ministry of Health and The Children's Hospital at Westmead. The Department of Health and Ageing provided funding for this project. We thank those authors who provided their conference materials for consideration, Kerrie Wiley for independently reviewing one of the included articles and Edward Jacyna for his assistance in locating material for this review. Note: * Records included in the review http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Australian and New Zealand Journal of Public Health Wiley

Strategies to improve vaccination uptake in Australia, a systematic review of types and effectiveness

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References (125)

Publisher
Wiley
Copyright
© 2012 The Authors. ANZJPH © 2012 Public Health Association of Australia
ISSN
1326-0200
eISSN
1753-6405
DOI
10.1111/j.1753-6405.2012.00897.x
Publisher site
See Article on Publisher Site

Abstract

H igh vaccination coverage remains crucial to reduce individual disease risk and to develop and maintain population‐based (herd) immunity. For Australian infants aged 12 and 24 months, coverage for nationally funded vaccines exceeds the countrywide target of 90%. However, coverage for such vaccines in adolescents and children aged 4 and over fails to meet this target. Uptake of nationally funded seasonal influenza vaccine is estimated at 75% for adults aged 65 years and over, which is higher than uptake of the 23‐valent pneumococcal polysaccharide vaccine (54%) funded nationally for the same group. For the same vaccines in Aboriginal and Torres Strait Islander peoples aged 15 years and over, uptake is less than half of this. Certain populations remain at higher risk for under‐immunisation, including Aboriginal and Torres Strait Islander people and others experiencing deprivation or social exclusion. Similarly, certain medically, behaviourally and occupationally at‐risk groups are at greater risk of vaccine preventable diseases (VPDs), thus enhancing the importance of vaccination in these groups. A review of international evidence for interventions to improve vaccination uptake highlighted that multi‐component strategies had positive effects on adults and children. However, some of these strategies alone had less convincing evidence of effectiveness. This review included only a minority of Australian studies, all conducted prior to 2000. Other international reviews have included studies from Australia but focus only on specific strategies and/or target groups. The evidence for strategies to improve vaccination uptake identified in international reviews may have reduced relevance given some unique aspects of Australia's national immunisation program (NIP). This systematic review aims to profile and critique available evidence of strategies to improve vaccination uptake in Australia and evaluate their effectiveness. Methods The relevant literature was identified, classified and critiqued as follows. This is summarised in Figure 1 . 1 Search strategy and review process based on PRISMA a statement. Search strategy Peer‐reviewed literature was identified by searches conducted in electronic bibliographic databases by a medical librarian, the third author. Databases included OVID Medline (1948 to April Week 2, 2011), OVID EMBASE (1980 to Week 16, 2011), OVID PsycINFO (1987 to April Week 3, 2011), Informit databases (Health subset), and CINAHL via EBSCO (1982–2011). A combination of database‐specific controlled vocabulary and general free text terms were used. The main controlled vocabulary terms were ‘immunisation’, ‘immunisation programs’, ‘vaccines’ as well as terms for individual VPDs and associated vaccines. Controlled vocabulary terms for other key concepts associated with strategies to improve uptake were also searched and combined with the immunisation, vaccines and disease terms. Free text terms representing all major concepts were also used in combination with the controlled vocabulary terms to maximise retrieval. This search strategy was applied from early 1997, when the formal Immunise Australia program was established, through to May 2011. Results were limited to humans and English language. Reference lists of all identified literature were scanned to locate additional items. A copy of the search strategy is available from the authors upon request. Grey literature (material not published in peer‐reviewed sources) was identified through hand searching all Public Health Association of Australia (PHAA) National Immunisation Conference abstracts from 1998 to 2010, scanning state/territory health department and state‐based general practice network websites as well as consulting with experts in the field. Copies of potentially relevant conference posters and/or presentations were requested from primary authors. In addition, the Australian Digital Theses Program database, the National Library of Australia's Trove database and the Australian Resource Centre for Healthcare Innovations (ARCHI) were searched systematically using the controlled vocabulary terms described above. Eligibility criteria, classification of studies and data extraction To be included, studies must have reported original research about, or evaluation of, one or more interventions to improve uptake of one or more vaccines available in Australia. They must have included a quantitative measure of uptake as a primary outcome with studies describing uptake in the absence of an intervention or reporting only other outcomes (i.e. descriptive or qualitative) excluded. Also excluded were evaluations of the introduction of vaccines onto the Australian Government funded NIP and routine implementation of school‐based vaccination programs as these were considered baseline practice in Australia. The title and abstract of all studies were screened according to the inclusion criteria. The first two authors undertook this independently with discrepancies resolved by discussion with the third author. A data extraction form was developed and pilot tested on five randomly selected studies, and refined accordingly. The first two authors independently extracted relevant information from each study. Study design was classified according to Irwig & Cumming study types in population health research. Interventions in identified studies were classified into four categories, as defined by The Task Force on Community Preventive Services and ten major target groups, based on those in the Australian Immunisation Handbook 9 th Edition. Critique of published studies In light of considerable heterogeneity in study design, a combination of two validated and recommended tools for assessing quality in public health interventions were combined and applied to studies published in the peer‐reviewed literature. The tool assessed reporting quality, sampling, measurement, data analysis, interpretation of results and study design. The first two authors independently assessed studies using the modified quality scale then met to discuss and gain consensus on the final quality rating (1=weak, 2=moderate, 3=strong). One article with a potential conflict of interest was assessed by an independent reviewer and the first author. Assessing the quality of grey literature was not feasible due to substantial differences in reporting format and the limited information available in these sources. Synthesis of results The primary outcome was a change in vaccination uptake in the specified target group. Reporting of the principal results is based on the PRISMA statement. Table 1 combines included studies by intervention type and target group. 1 Target groups and intervention types reported by first author (publication year) of included study (n=49). Newborns Children Adolescents Adults Elderly Aboriginal and Torres Strait Islander peoples Pregnant women Medically at risk a Behaviourally at risk b Occupationally at risk c TOTAL Increase community demand Banks (2008) Bartu (2006) Hawe (1998) Kirby (2010) Tomney (2010) Van Buynder (2010) Skinner (2000) Juraskova (2011) Byrnes (2006) Puech (1998) Wallace (2008) d Thomas (2008) Wallace (2008) d Ferguson (2010) Lennox (2007) Devine (2007) Ballestas (2009) Waddington‐ Powell (2008) Scott (2010) Fullerton (2010) De Alwis (2010) e 20 Enhance access Bond (1998) Ressler (2008) Brown (2010) Elia (2010) f Smith (2010) Gill (2010) g Reeve (2008) Elia (2010) f Gill (2010) g Elia (2010) f Gill (2010) g Elia (2010) f Gill (2010) g Grant (2005) Piper (2008) Gold (2000) SESIAHS (2008) Fredricks (2010) McDonald (2007) Rogers (2005) Howe (2009) Elia (2010) f De Alwis (2010) e 16 Provider based interventions Ali (2009) Frank (2004) Finlay (2008) Kerse (1999) McIntyre (2003) Irwin (2002) Lake (2008) Colgrave (2010) De Alwis (2010) e 9 Regulatory interventions Connors (1998) Lam (1998) Bond (2002) Smithers (2003) Stewart (2002) Helms (2011) 6 TOTAL 2 14 4 4 8 4 0 6 3 12 Column Total: 51 h Row total: 57 i a. Those whose current or past health status places them at increased risk of acquiring a vaccine preventable disease, excluding pregnant women (tabled separately). b. Those whose engage in risk taking behaviour which places them at increased risk of acquiring a vaccine preventable disease. c. Those who engage in an occupation which places them at increased risk of acquiring a vaccine preventable disease and thus they have specific vaccination recommendations. In this review, these groups include health care workers and Australian Defence Force personnel. d. Wallace (2008) listed in 2 cells as strategy targeted both Aboriginal and Torres Strait Islander peoples & elderly. e. De Alwis (2010) listed in 3 cells as it covers multiple intervention types. f. Elia (2010) listed in 5 cells as strategy targets the entire age spectrum and health care workers. g. Gill (2010) listed in 4 cells as targets entire age spectrum. h. Three articles are listed more than once under an intervention type, however are only counted once the row total. i. One article is listed more than once under a target group, however is only counted once the column total. Results The initial search identified 1,576 articles after removing duplicates with 49 articles meeting the inclusion criteria ( Figure 1 ). Complete posters and/or oral presentations were requested from 23 authors of PHAA conference abstracts with 18 supplying material for consideration. Among the 49 included articles, 32 (65%) were published in peer‐reviewed journals, 14 (29%) were conference abstracts or presentations and three (6%) were reports. There was an average of two to three studies published per year from 1997–2007 with more than half published from 2008 onwards (n=28). Studies were conducted across all Australian states and territories, although more than half (n=31) were from New South Wales and Victoria. A summary of the key attributes of included studies is available online at http://www.ncirs.edu.au . Of the 49 included studies, 37 (76%) were concluded to be successful or effective; nine (18%) were unsuccessful or had a lower‐than‐expected increase in coverage; and three (6%) studies were unable to determine effectiveness of their intervention. Intervention types The four intervention categories included: those which increase the community's knowledge or awareness about vaccination (increase community demand, n=20); those which reduce the cost, or increase convenience, of accessing vaccination services (enhance access to vaccination, n=16); those aimed at vaccine service providers (provider‐based interventions, n=9); and those which establish guidelines, policies or regulations to increase compliance or mandate vaccination (regulatory interventions, n=6). In the categories of increasing community demand and provider‐based interventions, the most effective and common strategies were patient reminder/recalls and provider reminders. Education for the public and providers (either alone or as part of a multi‐component strategy) had variable impact on uptake, with increases less substantial or direct when compared with reminder/recalls. Also effective were integration of vaccination status checks into routine health assessments, individual provider support, and targeted promotion campaigns in the mass media, although studies of these interventions were minimal and confined to particular target groups and vaccines. For enhancing access, catch‐up plans for those overdue for vaccination were particularly effective, often reducing the percentage of those overdue by more then 50%. The two studies involving an accelerated vaccination schedule for hepatitis B showed an increase in the overall completion rate compared with the standard schedule. Results from the few studies of home visits for routine childhood vaccination highlighted their effectiveness, particularly when targeting Aboriginal and Torres Strait Islander children. The same effectiveness was observed for expanding access in hospitals and vaccination clinics in public settings. There were several effective regulatory interventions that were beyond ‘baseline practice’ of funding vaccines on the NIP and school‐based vaccination programs. These included national parental incentives; the maternity immunisation allowance (MIA) and linking vaccination to the child care benefit as well as a jurisdictional hepatitis B vaccination policy for high‐risk infants then subsequently for all newborns. All other regulatory interventions primarily focused on provision of funded vaccine coupled with mandatory vaccination policies for health care workers (HCWs) and were implemented at a jurisdictional and/or organisational level. The small number of studies showed limited effectiveness of this strategy. Target groups and vaccines Children were the most commonly targeted group (n=14) and pregnant women were the least targeted (n=0); see Table 1 . The most commonly targeted vaccines were those for influenza (H1N1 pandemic and seasonal influenza, n=21), followed by hepatitis B vaccine alone (n=13), then any combination of vaccines included on the NIP for children under seven years of age and/ or for Aboriginal or Torres Strait Islander peoples (n=11). Study design Major categories of study designs included ‘descriptive’ (n=22), ‘before/after’ (n=12), and ‘analytical’ (n=15). A higher proportion of studies reported in grey literature had descriptive (65%, 11/17), and ‘before/after’ designs (35%, 6/17) compared with published studies (34%, 11/32 and 19%, 6/32). The 15 analytical studies, which addressed questions of causality were all published in the peer‐reviewed literature. Nine were randomised controlled trials (RCTs) with the remainder cross‐sectional and cohort studies and a quasi‐RCT. Outcome indicators Of the 49 included studies, 29 collected baseline uptake for comparison. Differences in uptake before and after interventions varied vastly. Two studies reported large differences (>40%) following catch‐up programs in at‐risk populations, the highest of any studies. Three studies reported moderate differences (21–40%) following a number of interventions including: routine reminder letters for NIP vaccines for four‐year‐olds; a multi‐component promotion and education program for HCW influenza vaccination; and the introduction of a neonatal hepatitis B vaccination policy for medically at‐risk infants. The majority of studies with baseline uptake (n=15) reported a small difference post‐intervention (1–20%). Among studies with baseline data, only one reported no improvement in uptake which was observed three months after the introduction of a new vaccination policy for HCWs in one hospital. The remaining nine studies mentioned baseline uptake only, without specifying any comparative increase following the intervention. Two studies used the number of vaccines ordered as an indicator of vaccine uptake. These demonstrated satisfactory increases in vaccine ordering following an educational campaign and jurisdictionally centralised provision of free hepatitis B vaccine to those newly diagnosed with hepatitis C. However, this method could only act as a proxy for estimating uptake as the amount of wastage could not be accurately measured. Quality of included studies published in peer‐reviewed literature Only studies reported in the peer‐reviewed literature (n=32) were assessed using recommended tools (see Methods). Overall, most studies scored high (n=18) to moderate (n=10) for quality. In general, studies scoring highly used analytical designs (excluding quasi‐RCTs), described interventions thoroughly, utilised appropriate data analysis methods, and provided reasonable and meaningful interpretations of the results. Studies with a low quality score were less geared towards measuring change in a rigorous manner. Their deficiencies were mainly poor description of data collection and analysis methods as well as unclear outcome indicators, thus reflecting potential measurement biases. Generally, all studies had relevant and detailed descriptions of the intervention, sample size and target group. Discussion This review found 49 studies reported since 1997 that evaluated interventions to improve vaccination uptake in Australia. There was considerable heterogeneity in interventions, target groups, settings and study designs. Hence, for any one intervention there is only a small amount of evidence available which is itself of variable quality. In this context, most strategies reviewed had some impact on increasing vaccine uptake with only one ineffective strategy reported. Catch‐up plans demonstrated the greatest impact on uptake yet recall/reminders for patients and provider reminders were the most commonly‐evaluated strategies and had the highest level of evidence, each with two RCTs demonstrating their effectiveness. No single study evaluated the effects of different types of patient reminder/recalls, although this has been done internationally to show that all types are effective, telephone calls more so than others. There was no evidence for the effectiveness of new technologies (e.g. text messages, smart phone ‘apps’) for recall/reminders. There is an urgent need for these methods to be evaluated in the light of the proven effectiveness of reminders in general. There was some evidence of the effectiveness of several individual strategies to increase community demand for vaccination. Promising results are seen with integrating vaccination status checks into routine health assessments for prisoners and those with intellectual disabilities. This strategy should also be evaluated in other population groups targeted for routine health assessments. Despite measurement limitations, evidence was positive for the use of mass media campaigns to increase community demand for nationally recommended and/or funded vaccines in certain target groups. This is supported by an earlier Australian study, however international evidence is insufficient to support the use of this strategy. Only one included study evaluated education for a specific community in isolation. In all others, education was included as part of a multi‐component intervention which makes it challenging to detect the effectiveness of this strategy on its own. This, along with the need for a longer intervention period to observe the translation of knowledge to behaviour change, explains why this and other international reviews have found insufficient evidence to demonstrate the effectiveness of any form of education in increasing uptake. Reminders and education/support for providers were effective and widely used particularly in relation to at‐risk patients. In contrast, international evidence is mixed on the effectiveness of provider education alone, yet its use in combination with other provider‐based strategies is recommended. International evidence also recommends standing orders and provider audit and feedback, although this review identified insufficient evidence to draw any strong conclusions about the effectiveness of these strategies in the Australian context. International debate around the effectiveness of provider incentives remains unresolved. Despite the availability of ecologic evidence of their effectiveness in Australia, no studies of this strategy were eligible for inclusion in this review. Most of the evidence for strategies to enhance access to vaccines was in at‐risk groups. As has been demonstrated internationally, an accelerated hepatitis B schedule improved uptake in injecting drug users, however there was no evidence of the effectiveness of accelerated schedules for other multi‐dose vaccines. Home visits for routine childhood immunisation were particularly effective in Aboriginal and Torres Strait Islander communities, in contrast to mixed international evidence of the effectiveness of this strategy across the age spectrum. Expanding access in hospital settings as a single intervention was effective when targeting medically and occupationally at‐risk groups, which is in contrast to international evidence. The effectiveness of reducing out‐of‐pocket costs for vaccination in increasing uptake is well established. This strategy is particularly effective in those experiencing financial deprivation, yet has reduced effectiveness where public perception about the disease or vaccine is vexed (e.g. influenza). Inherent in all included studies was the provision of free vaccine under the NIP, hence this strategy was not specifically evaluated. This should be taken into consideration when interpreting the results and comparing these to evidence from other countries where payment for the vaccine is often required. As has been observed in similar systematic reviews, studies of regulatory interventions were limited. This may be a result of the exclusion of studies evaluating the introduction and funding of vaccines under Australia's NIP, which has an established body of evidence demonstrating its effectiveness. One included study provided good evidence of the effectiveness for legislated parental incentives for maintaining up‐to‐date vaccination of their children, which is also supported by another Australian study, although international evidence to support this strategy remains insufficient. There is good international evidence that linking immunisation to school or childcare entry is effective, although no identified studies formally evaluated this in the Australian context. As numerous strategies may be implemented in addition to regulatory interventions during the evaluation period, it is difficult to measure the sole impact of these interventions on vaccine uptake. The use of two or more strategies in combination appears to be an effective approach for improving vaccination uptake in Australia. Most commonly, multi‐component strategies focus on increasing community demand for, and enhancing access to, vaccination. Provider‐based strategies are occasionally incorporated and regulatory interventions usually underpin these and are evaluated in isolation. Results from international reviews overwhelmingly support the use of multi‐component strategies to increase coverage for children and at‐risk groups. There was a lack of evidence for strategies to improve vaccination uptake in particular ‘at‐risk’ groups. No included studies focused on pregnant women, possibly as they are a relatively new target group for routine vaccination. Also limited was evidence of strategies to increase vaccine uptake in behaviourally at‐risk groups such as prisoners and injecting drug users. A more concerted effort to measure uptake in these groups is needed. Notably, there were a small number of strategies targeting Aboriginal and Torres Strait Islander peoples who suffer higher rates of VPDs. This may be the result of a reporting deficiency, as it is known that many strategies are being implemented in this target group. Action to collate, review and selectively evaluate strategies to increase vaccine uptake in this group is urgently needed. A major limitation of included studies was their design and outcome measurement. In many studies it was not possible to sufficiently determine the impact of the intervention because of a lack of baseline measurement or a control group. In addition, outcome indicators were frequently poorly defined and were not uniform across studies, thus limiting comparison. Although the majority of studies reported some increase in uptake, less than half quantified the relationship between this and the study factors. Future evaluations should aim to use appropriate and valid measurement methods, compare results to baseline or existing coverage estimates, and acknowledge contextual factors which may influence findings. Only one study utilised behaviour change theory. Interventions which include a behavioural change component can be enhanced by applying a clearly articulated theory which is backed by evidence of its effectiveness on behaviour. This will allow the identification of variables thought to cause change in behaviour, and facilitate the accumulation of evidence of effectiveness across different contexts, populations and behaviours, as well as assist in the understanding of the mechanisms of change. Staff employed to implement immunisation programs conducted many included studies in‐house, often with limited capacity or resources to undertake scientifically rigorous evaluations. This is a common occurrence in the evaluation of public health interventions, although without close ties between evaluation and program implementation there is a risk of wasting resources on ineffective or even counter‐productive programs. Evaluating existing strategies to improve vaccination uptake in Australia and disseminating the findings through more publicly‐accessible mechanisms should be encouraged. In doing so, a recommended framework, such as the TREND statement (available at http://www.cdc.gov/trendstatement/docs/TREND_Checklist.pdf ) should be applied to enhance utility and transparency. The value of including data from different types of studies in systematic reviews of health interventions is being increasingly recognised, although it comes with known theoretical and practical challenges. In this review, grouping ‘similar’ interventions (i.e. reminder/recall) and considering these as a collective body of evidence may have disguised important differences between individual interventions and limited full consideration of the contextual factors which would undoubtedly impact on effectiveness. However, efforts were made to tabulate the context of interventions so comparisons could be made. Aspects of the review process, such as the categorisation of studies and quality assessment, were potentially open to reviewer bias. However, the use of established frameworks defining intervention type and study design, independent assessment and third party verification all assisted in reducing the impact of this potential bias. A rigorous process was used to combine two validated quality assessment tools which led to the development of a new tool. The final tool allowed for a more extensive assessment of study quality than the two original tools individually, although it was not specifically validated. Publication bias and partiality in the location of studies was not felt to be a major limitation in this review as multiple bibliographic databases were searched, numerous experts were consulted and grey literature was extensively searched and included. However, it is notable that null findings were more frequently reported in peer‐reviewed rather than grey literature. Excluding studies that could not demonstrate the impact of a particular strategy on vaccine uptake may have reduced the extensiveness of reporting of known strategies. Conclusion Despite the limitations in the quality and quantity of included studies, available evidence highlighted some potentially effective strategies to improve vaccination uptake in Australia. In contrast to the system‐wide demand for their use, activities to increase vaccination uptake are infrequently and often inadequately evaluated. There remains an elusive pool of unpublished evidence about how to improve vaccination uptake; barriers to obtaining and disseminating this information need to be identified and overcome. In addition, new, widely used and/or potentially effective strategies with limited evidence need to be identified and appropriately evaluated using the most practical and scientifically rigorous designs within the resources available. In a climate where funding and resources are finite, the development of such an evidence base is essential to avoid the continued use of ineffective interventions. It is hoped that those desiring to improve the performance of vaccination programs can use this base of evidence in conjunction with that from overseas to inform and guide their efforts. In addition, areas for future investigation of strategies to raise and sustain vaccination uptake can also be guided by the results of this review. Acknowledgements The National Centre for Immunisation Research and Surveillance is supported by the Australian Government Department of Health and Ageing, the NSW Ministry of Health and The Children's Hospital at Westmead. The Department of Health and Ageing provided funding for this project. We thank those authors who provided their conference materials for consideration, Kerrie Wiley for independently reviewing one of the included articles and Edward Jacyna for his assistance in locating material for this review. Note: * Records included in the review

Journal

Australian and New Zealand Journal of Public HealthWiley

Published: Aug 1, 2012

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