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Abstract
Objective Vaccination in pregnancy (VIP) is a protective measure for pregnant individuals and their babies. Healthcare provider’s (HCP) recommendations are important in promoting VIP. However, a lack of strong recommendations and accessible resources to facilitate communication impact uptake. This study sought to determine the extent of and characterise the resources available for parent-provider vaccine communication in pregnancy in Canada using a behavioural theory-informed approach.
Design Scoping review.
Methods In accordance with the JBI methodology, nine disciplinary and interdisciplinary databases were searched, and a systematic grey literature search was conducted in March and January 2022, respectively. Eligible studies included resources available to HCPs practising in Canada when discussing VIP, and resources tailored to pregnant individuals. Two reviewers piloted a representative sample of published and grey literature using inclusion-exclusion criteria and the Authority, Accuracy, Coverage, Objectivity, Date, Significance guidelines (for grey literature only). Sixty-five published articles and 1079 grey reports were screened for eligibility, of which 19 articles and 166 reports were included, respectively.
Results From the 19 published literature articles and 166 grey literature reports, 95% were driven by the ‘Knowledge’ domain of the Theoretical Domains Framework, while n=34 (18%) addressed the ‘Skills’ domain. Other gaps included a lack of VIP-specific tools to address hesitancy and a lack of information on culturally safe counselling practices.
Conclusion The study suggests a need for resources in Canada to improve VIP communication skills and improve access to vaccination information for HCPs and pregnant individuals. The absence of such resources may hinder VIP uptake.
- public health
- medical education & training
- patient-centered care
- primary health care
Data availability statement
Data are available upon reasonable request. Data are available upon reasonable request. Data include results of database searching, results of grey literature search and data extraction form of published literature. Additional information (ie, scoping review protocol) has been made available online at Open Science Framework (available online: https://doi.org/10.17605/OSF.IO/PVJSQ).
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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STRENGTHS AND LIMITATIONS OF THIS STUDY
Used behavioural theory-informed approach to classify literature and identify gaps.
Comprehensive search strategy developed in consultation with a research librarian.
Inclusion of published and grey literature to find wide range of information sources.
Constrained by focus on Canadian context, limiting the generalisability of findings.
Limited by ‘English language resources’ potentially omitting relevant studies.
Introduction
The Canadian National Advisory Committee on Immunization (NACI) recommended that all pregnant individuals receive the inactivated influenza vaccine,1 the tetanus-diphtheria-acellular pertussis (Tdap) vaccine2 and the COVID-193 vaccine since 2007, 2018 and 2021, respectively. These vaccines are effective at preventing maternal and/or neonatal mortality and morbidity,3 4 and are safe for use during pregnancy.3 5 Despite these recommendations, many pregnant individuals struggle with their decision to vaccinate during pregnancy.6 Uptake of vaccination in pregnancy (VIP) remains low7 8 for several reasons including safety concerns.6 9 10
Recommendations from healthcare providers (HCPs) are a strong predictor of vaccine uptake and an important facilitator of VIP.6 11–13 Effective patient-provider vaccine communication in pregnancy is needed because: (1) suboptimal VIP coverage with existing vaccines globally is a missed opportunity to improve maternal and infant health, (2) new vaccines designed to confer neonatal protection against pathogens through VIP are being developed and (3) VIP is correlated with subsequent infant vaccination.14 However, there is limited availability of resources and strategies to support patient-provider vaccine communication15 and interventions that support vaccine communication are not easily accessible to providers.16 One study in Australia found that only 43% of midwives felt equipped to administer vaccines because of inadequate vaccination education.17 In Canada, rural HCPs similarly felt underprepared to discuss vaccination, because childhood immunisation responsibility was provided by public health.15 This alludes to the importance of easily accessible resources that HCPs can use to develop communication skills, especially when engaging in difficult conversations with vaccine-hesitant patients.
The implementation of evidence-based practices like discussing, offering, administering and/or receiving vaccinations during pregnancy requires behaviour change at both the individual (eg, patient and provider) and organisational (eg, system and policy) levels. To change behaviour, it is critical to understand what factors influence behaviour, that is, drivers of current practice and barriers to change. The Theoretical Domains Framework (TDF) applies a theoretical lens through which cognitive, social and environmental influences on behaviour can be examined,18 and it is based on the COM-B theory, according to which, for behaviour (B) change, the individual needs to be capable (C), motivated (M) and have the opportunity (O) for change.19 For the TDF development, initially 12 domains were distilled from 128 theoretical constructs,20 after which validation and refinement led to 14 domains21 (figure 1). The TDF domains allow for a systematic and theory-based approach to inform intervention design and implementation.18 Additionally, behavioural theory may help inform what contexts interventions are effective in, and provide hypotheses of the processes that regulate behaviour change and a nuanced understanding of the mechanisms of action by which behaviour change occurs.18 Applying implementation science and behavioural sciences theory allows for a comprehensive understanding of the gaps in care and potential lack of effective communication strategies in VIP.
Theoretical Domains Framework definitions.18
We undertook a scoping review to systematically characterise the literature and resources available to HCPs in the current Canadian VIP setting. Given the calls for use of theory to understand practice change in intervention,22–24 this review used the TDF to classify both the grey and published literature based on the information presented in the resource. Our aim was to determine what gaps exist and organise them according to what aspect of behaviour change they target. To our knowledge, there are no systematic or scoping reviews on the topic specific to the Canadian context. A protocol was developed a priori. The protocol was registered on Open Science Framework on 24 May 2022 (available online: https://doi.org/10.17605/OSF.IO/PVJSQ).
Methods
Defining the study and research question
The scoping review was conducted in accordance with the JBI methodology for scoping review.25 26 Both the published and grey literature were searched. Separate, but related, research questions were defined for both sources. Review of the published literature was guided by the following research questions: (1) ‘What has been tried or what is known about strategies to support vaccination discussions in pregnancy in Canada?’ and (2) ‘What vaccination information is available to support HCPs discussion of VIP?’, whereas grey literature was guided by the following question: ‘What resources are available in the grey literature for practitioners to consult or use to discuss vaccination during pregnancy in Canada?’. The broader published literature questions were designed to counteract the limit of Canadian-based studies. The Population-Concept-Context framework was used to inform the review questions (see online supplemental file 1).
Supplemental material
Search strategy
The search strategies were developed in consultation with a research librarian (KAH).27 For the published literature, an initial limited search on Google Scholar was undertaken to identify relevant studies. Keywords and subject headings were used to develop a full search strategy for Medline via OVID, then translated for each database (see online supplemental file 1). Reference lists of included sources of evidence were screened for additional studies. Based on the inclusion criteria, studies published since 2010 were incorporated because the influenza vaccine was universally recommended during pregnancy after the 2009 H1N1 pandemic. Resources for a comprehensive range of healthcare professionals were included, including obstetricians, family physicians, midwives, nurses (including registered nurses, licensed practical nurses, nurse practitioners), doulas, lactation consultants and pharmacists. These professionals were considered within the scope of our research. As per the exclusion criteria, records were excluded if referenced individuals were receiving care for purposes other than pregnancy, HCPs were not engaged in providing perinatal services or sources did not reference the Canadian context. See the protocol for full inclusion and exclusion criteria.
Databases searched in March 2022 for the published literature included: Medline and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations and Daily (OVID), Embase (OVID), APA PsycInfo (OVID), Cochrane Central Register of Controlled Trials (Cochrane Library), CINAHL Plus with Full Text (Ebsco), Academic Search Complete (Ebsco), CAB Abstracts (Ebsco), Family and Society Studies Worldwide (Ebsco) and Scopus (Elsevier). Full database search strategies are available in online supplemental file 1.
Grey literature was searched using a multistep methodology of search engines and targeted website browsing, as per the University of Toronto’s Guide to Comprehensive Searching in the Health Sciences using grey literature databases.28 In addition to Google, grey literature resources searched included: Canadian Electronic Library (government documents), Canadian Research Index (government reports), ProQuest Dissertation and Theses, The Conference Board of Canada, BC Guidelines (GPAC), CPG Infobase: Clinical Practice Guidelines, Journal of Obstetrics and Gynaecology Canada, and Disease Prevention and Control Guidelines (Canadian Immunization Guide 7th Edition).
Grey literature search was conducted in January 2022 by MSS. The top 100 sites as ranked by the Google.com Page/Rank analysis were evaluated and narrowed using predefined criteria to eliminate irrelevant sites.29–31 Initial screening was guided by the Authority, Accuracy, Coverage, Objectivity, Date, Significance (AACODS) checklist to determine site relevancy.32 This criterion excluded a site if it was (1) clearly commercial; (2) seemingly untrustworthy or unreliable (eg, personal homepages); and/or (3) did not contain relevant information or information from primary sites.31 As per the ‘authority’ criterion of the AACODS, fewer than 100 sites were screened if consecutive sites were irrelevant. Search concepts included: ‘vaccination’, ‘pregnancy’ and ‘health promotion’. Full list of search terms is available in online supplemental file 1.
Evidence selection
Following the database searches, records were exported and uploaded into Covidence by KAH, and duplicates were automatically removed. Of 1257 titles/abstracts, 50 were randomly selected and were piloted in Excel to evaluate selection criteria, after which all were screened by two independent reviewers (MSS, MMA). All relevant full-text records were then independently assessed by the same team members. Disagreements between reviewers were resolved through discussion with additional reviewers (EC, DAM).
After the AACODS screening to identify reliable websites in the grey literature, we applied the study inclusion-exclusion criteria to select evidence. Two reviewers (MSS, MMA) piloted the grey literature search tracking form. Discrepancies in assigning relevancy were resolved though consultation with senior authors (EC, DAM). MSS conducted the grey literature search independently, presenting results to research team to confirm content validity.
The scoping review is presented in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews (figure 2) and the completed checklist is available in online supplemental file 2.
Supplemental material
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 flow diagram for new systematic reviews.
Data extraction
Covidence was used to extract published literature data by the lead reviewer (MSS). Twenty per cent of articles were randomly chosen, and their data were extracted in duplicate for accuracy by MMA. For the grey literature, the reviewers developed an Excel data extraction tool. See online supplemental file 3 for data extraction forms. Disagreements were resolved through discussion and with an additional reviewer(s) (EC, DAM).
Supplemental material
Data analysis and presentation
Resources were classified into the 14 TDF domains by lead reviewer MSS. All published literature resources were independently classified by AMP. A resource could be classified under several domains. Only evidence-based sources deemed meeting the AACODS guidelines were included in the analysis.
Patient and public involvement
A patient research partner (MB), trained in Patient and Community Engagement Research, was integrated into our research team to ensure that the priorities and preferences of patients were considered throughout the study. Our patient partner actively participated in the development of inclusion and exclusion criteria, classification and analysis of data, as well as in the preparation and editing of this manuscript. Furthermore, the patient partner will continue to be involved in knowledge dissemination activities related to this study. The inclusion of a patient research partner in the study design and execution, along with their participation in manuscript preparation and dissemination efforts, serves as an important step in ensuring the meaningful engagement of patients in research.
Results
Published literature
As illustrated in the PRISMA flow diagram (figure 2), a total of 2486 articles were identified. After removal of duplicates, 1275 titles/abstracts were screened, 65 full texts were assessed and 19 articles were included in the review. Ten per cent (n=2) of the published articles discussed COVID-19 vaccination, 47% (n=9) discussed Tdap, 16% (n=3) discussed influenza and the remaining articles discussed VIP generally. Statements from one professional organisation, the Society of Obstetricians and Gynaecologists of Canada (SOGC), and from the Canadian NACI, were referenced 4 (21%) and 14 (74%) times, respectively. Twenty-six per cent of publications referenced statements from both organisations. No articles discussed counselling those who identify as black, indigenous or people of colour (BIPOC). Only three (n=3/19) of the articles were primary research studies, including two which were cross-sectional studies33 34 and a non-experimental, qualitative study.15 The remaining 16 articles were expert opinions, commentaries, editorials or letters to the editor. See online supplemental table 1 listing articles and their evidence level.35
Supplemental material
Seventy-four per cent (n=14) of articles were predominantly content based, that is, focused on providing facts or information to educate HCPs on VIP (eg, common vaccine side effects, data on efficacy, disease burden and recommended trimester). Information presented in the articles was classified according to the TDF domain they addressed. Classifying articles according to what aspect of behaviour change they addressed, we found that all articles addressed the ‘Knowledge’ TDF domain, 12 reflected ‘Beliefs about consequences’, 1 addressed ‘Environmental Context and Resources’ and 1 addressed ‘Social/professional role and identity’. Namely, Hughes discussed how pharmacists play an important role in bridging the gap between primary care physicians and public health to ensure counselling during pregnancy is not missed.36 None addressed the ‘Skills’ domain. See online supplemental table 2.
Grey literature
A total of 1079 grey reports were screened for eligibility and 166 reports were included. Eighty-six organisations were represented, with most reports originating from the Public Health Agency of Canada and NACI, a professional organisation (SOGC) and the public health organisations from Canadian provinces (Public Health Ontario, Manitoba Health, Alberta Health Services, British Columbia Centre for Disease Control). See online supplemental table 3. Eighty-one reports originated from federal-level organisations that applied to all of Canada. Eighty-nine per cent (n=148) of reports were content based that aimed to provide information or answer commonly asked questions. Only 11% (n=8) of resources provided education on how to counsel a pregnant patient on vaccination or address hesitancy specifically in pregnancy. A comprehensive list of resource types is available, see online supplemental table 4. The primary target audience for 63% (n=104) of the relevant records were HCPs, and only 0.6% (n=1) of resources were intended specifically for midwives. Thirty per cent (n=30) of reports were patient facing with the implication of usage by an HCP and 6.6% (n=11) were intended for both HCPs and patients with separate sections. In terms of the vaccines represented, 42% (n=70) addressed COVID-19, 15% (n=26) addressed Tdap, 7% (n=11) addressed influenza and the remaining records addressed case-by-case vaccination exposure or as-needed vaccines, that is, travel vaccines. SOGC was referenced in 53 reports, NACI was referenced in 33 reports and both authorities were referenced in 29 reports.
Another key finding from the grey literature was that information sheets or ‘frequently asked questions’ documents represented a large portion of available resources; however, the title ‘Decision-Making Guide’ was only employed in a small number of documents. Only the resource for midwives explicitly discussed trauma-informed or violence-informed approaches to vaccine delivery. Only 2% (n=3) of reports were created to address vaccine hesitancy in BIPOC minority groups.
We used the TDF to determine which aspect of behaviour change was targeted by the grey and published literature resources, the majority of resources (95%, n=175) addressed the ‘Knowledge’ domain (n=175, 19/19 published articles and 156/166 grey reports) (see figure 3). Eighteen per cent of resources (n=34, 34/166 of grey reports and none of published articles) addressed the ‘Skills’ domain, 16% addressed ‘Beliefs about consequences’ (n=30, 18/166 grey reports and 12/19 published articles), 14% (n=25, 1/19 published articles and 24/166 grey reports) addressed the ‘Environmental context and resources’ and 3% (n=6, 1/19 published articles and 5/166 grey reports) addressed ‘Social/professional role and identity’. Lastly, only one resource (0.5%) addressed the ‘Goals’ domain. See online supplemental table 5. Overall, most resources provided information or content on the importance and safety of the recommended vaccinations, with few resources providing training material on how to use that content.
Visual representation of Theoretical Domains Framework classification.
Discussion
We undertook a scoping review to systematically characterise the literature and resources available to HCPs in the current Canadian VIP setting. Our main findings were that most resources, 74% (n=14) of published and 89% (n=148) of grey literature, were predominantly content based, for example, they focused on providing information in the form of facts or data (ie, safety data, disease prevalence, vaccine efficacy, etc). The minority of resources, 26% (n=5) of published and 11% (n=18) of grey literature, pertained to how to approach or how to engage in conversations about vaccination during pregnancy. Existing conversation tools were also not tailored towards hesitancy in pregnancy, specifically or towards the diverse Canadian population with only 2% (n=3) of total resources tailored to address vaccine hesitancy in BIPOC populations. While several resources discussed COVID-19 vaccination hesitancy in general, vaccination hesitancy in pregnancy was lacking. Arguably, hesitancy in pregnancy is nuanced, requiring a different conversation guide.
Given the calls for use of theory to understand practice change in intervention,22–24 this review used the TDF to classify both the grey and published literature based on the information presented in the resource. Applying implementation science and behavioural sciences theory allows for a comprehensive understanding of the gaps in care and potential lack of effective communication strategies in VIP. Ninety-five per cent of resources addressed the ‘Knowledge’ TDF domain, for example, intended to make the practitioner or the patient aware of something (disease burden, vaccine effectiveness or safety), whereas only 18% of resources addressed the ‘Skills’ domain, for example, ability to engage in vaccine communication. Although resources that focus on the ‘Knowledge’ domain importantly provide information on the benefits and risks of VIP, address misconceptions or misinformation and provide evidence-based information to support the safety and efficacy of vaccination, it is also important to have resources that focus on the ‘Skills’ domain, which provide training on how to effectively communicate with patients who may be hesitant about vaccination and how to address their concerns in a respectful and empathetic manner. Further, several domains (eg, beliefs about capabilities, emotion and behavioural regulation) were not addressed at all in neither the published nor grey literature, suggesting that there may be barriers from the other domains that are not targeted by the current Canadian literature.
Twenty-five per cent (4/19) of published articles in this scoping review were from Motherisk,37–40 a programme that provided evidence-informed counselling on drug safety in pregnancy and breast feeding to thousands of providers and patients per year,41 but has since dissolved. Furthermore, we found that several provincial or national websites redirected HCPs and pregnant patients to SOGC or NACI recommendations. However, much of SOGC materials, not including COVID-19 statements, are inaccessible to non-members creating a need for accessible resources. This highlights that there is a scarcity of trusted information sources for both the public and HCPs and concurs with findings from Karras et al16 and Mijović et al15 calling for better access to VIP resources like those provided for childhood immunisations.
In the grey literature, information sheets or ‘frequently asked questions’ documents represented a large portion of available resources. However, the title ‘Decision-Making Guide’, which may allow for more patient autonomy and shared decision-making during VIP conversations, was only employed in a small number of documents. Zipursky et al42 call for an ethics-based, shared decision-making guide to support VIP communication in Canada.
We found that resources tailored to counsel BIPOC populations were scarce, only 2% of the grey literature and no published literature. This is an important finding because visible minorities make up 13.6% of the population in Canada43 and may display vaccine hesitancy as a protective measure due to historic and contemporary instances of discrimination.44 Additionally, our study found that only a small proportion of the resources discussed were specifically tailored to midwives and addressed trauma-informed or violence-informed approaches to vaccine delivery. Trauma-informed care, in the context of VIP, involves addressing the impact of past traumas on one’s vaccination experience and subsequent decision-making process. A resource on trauma-informed practices would offer strategies for HCPs to emphasise the importance of informed consent, prevent retraumatisation or address potential triggers in the vaccination process and facilitate a collaborative approach that meets the pregnant person’s needs.45 The reason for trauma-informed care being limited to midwifery resources is unclear, but it could be that individuals with negative experiences within the mainstream healthcare system perceive midwifery as a viable alternative. Furthermore, only 0.5% (n=1) of Canadian resources acknowledged the unique role of midwives in discussions related to vaccination during pregnancy. This highlights the need for more resources that are tailored to the specific needs of midwives and address the unique challenges they may face when discussing vaccination with pregnant individuals. Although few organisations alluded to the importance of providing culturally safe care, that is, the Vaccine Hesitancy Guide, these resources did not adequately explain how to provide this care in relation to vaccinations.46
This scoping review reflected the need for resources that (1) aim to improve skills of HCPs when conversing with vaccine-hesitant pregnant people and (2) truly reflect the Canadian population and how and where they receive care during pregnancy and vaccinations (eg, recognising the role of pharmacists and midwives in VIP). These gaps in the Canadian context can be addressed by an interactive training tool, rooted in behaviour change theory, and open access to all in the VIP continuum. As an example, MumBubVax is an Australian initiative codesigned by physicians and midwives to optimise parent-provider communication.47 48 Rooted in behaviour change theory, MumBubVax is an interactive tool for HCPs to draw on during VIP discussions. A centralised compilation of individual training modules and conversation tools, as seen in MumBubVax, may bridge the discrepancy between content and the use of content in VIP discussions.
Strengths and limitations
This scoping review offered valuable insights into resources available for addressing vaccine hesitancy among pregnant individuals in the Canadian context by using a behavioural lens. The application of the TDF to classify both published and grey literature in terms of the barriers they addressed is a novel approach that highlights potential gaps in existing resources and areas for future research. Using a behavioural lens in the analysis of available resources was a strength of this study, as it allowed for a deeper understanding of health behaviour and provided a framework for understanding why people make certain decisions about their health. The inclusion of both published and grey literature in the review provided a comprehensive understanding of the resources available to address VIP vaccine hesitancy in Canada. Furthermore, the study is a valuable contribution to the field as it is one of the first to provide a comprehensive overview of the resources currently available to facilitate VIP discussions and classify resources according to the TDF.
However, there are some limitations to note. One limitation is that only publicly available resources were included in the grey literature search which may have resulted in an incomplete understanding of the resources available. Additionally, training tools and documents that are only accessible to members of professional societies, such as SOGC, were not accessed which may have provided a more comprehensive understanding of resource availability. Despite comprehensive and expert searching of the published literature coupled with the extensive grey literature searching, there is the potential that relevant resources were missed. Resources were also limited to English. Despite these limitations, the TDF used in this study has identified potential areas where more research and resources are needed to effectively address vaccine hesitancy among pregnant individuals.
Conclusion
VIP is an important protective measure for both pregnant individuals and infants and requires a strong recommendation from HCPs. Therefore, HCPs must have access to training materials that increase their VIP knowledge and confidence and develop their VIP communication skills. As highlighted by the published literature and grey literature search, although content-based tools exist, the Canadian VIP landscape lacks resources to develop counselling skills specifically for VIP hesitancy and resources that offer interactive, continuing vaccine education. Furthermore, resources to address VIP in a culturally safe, trauma-informed manner are lacking. These gaps may be addressed by a multicomponent health intervention. Additional research is required to create an intervention fitting of the Canadian context and the needs of HCPs and their patients in Canada.
Data availability statement
Data are available upon reasonable request. Data are available upon reasonable request. Data include results of database searching, results of grey literature search and data extraction form of published literature. Additional information (ie, scoping review protocol) has been made available online at Open Science Framework (available online: https://doi.org/10.17605/OSF.IO/PVJSQ).
Ethics statements
Patient consent for publication
Acknowledgments
We thank Medea Myers-Stewart for their assistance in creating the figures in this report.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Contributors MSS was responsible for the overall coordination of the review and drafting of the manuscript. EC, DAM and MMA contributed to the interpretation of findings, review of the evidence and decision to include studies as per the inclusion criteria. AMP provided insight on the use of the TDF in analysing the data. KAH developed the search strategy, conducted the published literature search and provided guidance on adhering to JBI and PRISMA guidelines. MD and MB provided critical feedback on the manuscript and helped shape the research, analysis and manuscript. All authors contributed to refining the inclusion/exclusion criteria, research question and aims of the review. EC supervised the project. All authors read and commented on drafts of this report. EC accepts full responsibility for this work, the conduct of the study, had access to the data and controlled the decision to publish.
Funding Funding for this work is provided through a grant from the Canadian Immunization Research Network (FRN 151944).
Disclaimer The funder was not involved in the scoping review process. All investigators are independent researchers and are not associated with the funder. Funding was obtained through a competitive grant process.
Competing interests EC spoke at educational events, without receiving any compensation, that were sponsored by Moderna in October 2022 and by Pfizer in December 2022 and is a non-voting member at the National Advisory Committee for Immunization. EC also received honorarium for speaking at educational events from Sanofi in June 2021 and September 2021 and Pfizer in June 2022.
Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.