Effectiveness of HIV prevention interventions targeting long-distance truck drivers: protocol for a systematic review and meta-analysis of global evidence

Abstract

Introduction

Globally, long-distance truck drivers’ (LDTDs) risk of exposure to HIV infections is higher compared with other populations in transit. Thus, several HIV prevention interventions have been implemented, though to a narrower extent compared with other most at-risk populations. Consequently, the effectiveness of such interventions is not well understood. Therefore, a review is warranted to inform policymakers on the most effective HIV prevention interventions targeted for LDTDs.

Methods and analysis

The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines were followed. Original peer-reviewed interventional studies involving LDTDs of either gender aged above 18 years, and reporting findings on HIV prevention interventions from any part of the world will be included. Non-empirical research studies like systematic reviews, literature reviews and scoping reviews will be excluded. A comprehensive search will be done from PubMed, Cumulated Index to Nursing and Allied Health Literature and other five databases to identify eligible studies. The Rayyan online platform will be used for the screening of titles and abstracts. For the meta-analysis, a random-effects meta-analysis using the ‘metafor’ package in R software will be done. Where specific studies may not report adequate data for meta-analysis, their findings will be presented qualitatively. The Cochrane Collaboration tool and Joanna Brigs Checklist will be used to assess the quality and risk of bias in the included studies.

Ethics and dissemination

A formal ethical approval is not required for this systematic review and meta-analysis. The findings will be presented at scientific conferences and published in open-access peer-reviewed journals to reach policymakers, stakeholders and the scientific community.

PROSPERO registration number

CRD42024505542.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• The study follows the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines which assures transparency in the planned systematic review process.

• The systematic review will collate evidence globally to inform on the most effective HIV prevention interventions targeted for long-distance truck drivers for adoption and use in resource-limited settings.

• Given that the searches will be conducted in the English language may mean that some studies written in other languages will be missed.

• The heterogeneity of the studies in the type of HIV prevention interventions, designs and outcomes may limit comparability in the pooled analysis.

• Owing to resource limitations, we will not be able to conduct the literature searches in certain databases that are not open access or available from the university library, like the Excerpta Medica database.

Introduction

Globally, an estimated 39 million people were living with HIV in the year 2022 according to the Joint United Nations Programme on HIV/AIDS.¹ During the same period, 1.3 million new HIV infections and 630 000 AIDS-related deaths occurred worldwide.¹ Notably, there has been a significant decline in new HIV infections in some regions like sub-Saharan Africa, where the burden is known to be the highest.¹Nevertheless, the progress in fighting new HIV infections may be delayed due to barriers that arise from certain hard-to-reach and most at-risk populations like long-distance truck drivers (LDTDs). The LDTDs are part of the larger key population groups accounting for 70% of all new HIV infections in 2021.² Moreover, LDTDs constitute a significant proportion of the female sex workers’ clients along various transport corridors.3,7

Despite evidence of high HIV prevalence rates among LDTDs, not much attention in the form of prevention research is given among them compared with other most at-risk groups. For instance, the global burden of HIV among LDTDs is estimated to be 3.86%, almost six times that of the general population.⁸ In the Asia and Pacific region, HIV prevalence rates of 19%,⁹15.97%¹⁰ and 15.22%¹¹ have been recorded among LDTDs. Elsewhere in the region of Eastern Europe and Central Asia, HIV prevalence rates of 1.54% among LDTDs have been reported.¹² The highest prevalence rates of HIV among LDTDs have been reported in sub-Saharan Africa. Here, HIV prevalence rates of 54.19% have been identified among LDTDs in South Africa,¹³ 35.29% in Uganda,¹⁴ 18.64% in Burkina Faso,¹⁵ 16.28% in Cameroon,¹⁶ 15.41% in Mozambique,¹⁷ 13.03% in Ethiopia,¹⁸ 10% in Nigeria¹⁹ and 17.8% in Kenya.²⁰ High-risk sexual behaviours,^{5 6 10 21 22} absence of spouses while on transit,^{5 23} limited access to HIV preventive services^{12 24} and substance use^{12 25 26} are among the key factors linked to the high HIV exposure rates among LDTDs. Moreover, the constant mobility and hard-to-reach nature of the LDTDs limit their access to biomedical and structural HIV preventive services, which are in most cases stationary.^{17 23 27}

Although the prevalence of HIV is high among LDTDs, up-to-date evidence of targeted prevention interventions is missing in various global settings. Further, given their constant mobility, LDTDs are known to bridge HIV infections from regions of high to low prevalence.^{3 6 17 21 22 28 29} Therefore, by virtue of their constant mobility, high-risk sexual behaviours, high prevalence of HIV and hard-to-reach nature, LDTDs have been recommended for targeted HIV prevention interventions.^{6 9 10 19} As such, various interventions among them peer-led HIV prevention educational campaigns, HIV counselling and testing, sexually transmitted infection (STI) screening and treatment, behaviour change communication on HIV prevention, mobile phone-based short message services (SMS) on HIV prevention, and consistent condom use promotion campaigns tailored for LDTDs have been conducted. Some of the places where these interventions have been implemented include India,30,32 Hong Kong in China,³³ Malawi,³⁴ Tanzania,³⁵ Morocco³⁶ and Kenya.37,42

Despite the implementation of HIV prevention interventions in various parts of the world, their actual effectiveness on HIV prevention among LDTDs remains unclear. This is especially true in the developing world where a significant majority of HIV prevention interventions are donor-funded.⁴³ Here, such interventions may be influenced to meet certain requirements during implementation and data collection in keeping with the priorities of the donor funders.⁴³ Eventually, the actual effect of such interventions may be deficient. Moreover, most developing countries lack the capacity to scale up and sustain donor-initiated HIV prevention interventions, further widening the gap in understanding the actual effectiveness of such interventions.⁴³ Furthermore, evidence of HIV prevention interventions is limited, especially in regions where HIV prevalence among LDTDs is known to be high like Asia and Pacific,^{10 11} Eastern Europe and Central Asia¹² and sub-Saharan Africa.^{13 15 17 19 20} For significant progress to be made in alleviating new HIV infections among LDTDs, evidence should demonstrate which interventions are most effective in enhancing preventive outcomes.⁴³ These outcomes include consistent condom use, HIV testing and counselling, number of sexual partners, drug and substance use prior to sexual interactions, knowledge levels on HIV/AIDS prevention, linkage and adherence to antiretroviral (ART) care and pre-exposure prophylaxis (PrEP) and postexposure prophylaxis (PEP) use among many more.⁴³ Evidence advocates for a clear understanding of the best modes of delivery and anticipated challenges surrounding HIV interventions for proper allocation of scarce resources and sustainability.⁴³ This would ensure that only the best evidence-based practices are adopted, especially in settings where HIV prevention resources are limited. Therefore, it is important to measure the effectiveness of the HIV prevention interventions targeted for LDTDs across diverse global settings.

Even with the high-risk profile of HIV among LDTDs, evidence of studies assessing the effectiveness of preventive interventions from a global perspective among them is limited. This is so despite the call from donors and policymakers to assess the effectiveness of HIV prevention interventions for better allocation of limited resources.^{1 2} Previously, only one systematic review has partly assessed HIV prevention interventions in sub-Saharan Africa.⁴³ Whereas the systematic review featured some studies on HIV prevention interventions, it also included others whose primary objective was not HIV prevention among LDTDs.⁴³ Thus, the study findings have limited generalisability as far as the effectiveness of HIV prevention interventions is concerned. Consequently, it is not clear which HIV interventions are the most effective in enhancing prevention outcomes among LDTDs. Therefore, a systematic review and meta-analysis will be conducted to gain insight into the most effective HIV prevention interventions targeting LDTDs from a global perspective.

Objectives

This review aims to systematically (1) describe the outcomes of various HIV prevention interventions targeted for LDTDs and (2) assess the effectiveness of the HIV prevention interventions through a pooled analysis of individual studies that share close similarities. Therefore, the proposed systematic review and meta-analysis will answer the following questions:

1. What are the outcomes of various HIV prevention interventions that have been implemented targeting LDTDs?

2. How effective are the HIV prevention interventions in enhancing preventive outcomes among LDTDs?

Methods

Protocol and registration

This protocol was written following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Protocols guidelines^{44 45} as given in online supplemental table 1. The protocol is registered in the International Prospective Register of Systematic Reviews under registration number CRD42024505542. The start date of this review was 5 February 2024 and the end date was 31 October 2024.

Eligibility criteria

For potential inclusion, studies will need to meet predetermined inclusion and exclusion criteria as highlighted below:

Inclusion criteria

For inclusion, studies will have to meet the following inclusion criteria:

Population: studies involving LDTDs who are also called long-distance truckers aged above 18 years will be included. In this study, LDTDs refer to long-distance truck drivers who are licensed to transport goods and services across diverse geographical borders and spend over 24 hours in transit to their destinations. Either male, female or any other gender of LDTDs will be included.

Intervention: studies reporting on HIV prevention interventions, for example, HIV testing and counselling, Health education on HIV/AIDS facts, peer-led HIV prevention campaigns, behaviour change communication on HIV prevention, mobile phone-based SMS educational campaigns on HIV prevention, STI screening and treatment, ART adherence campaigns, condom promotion campaigns, PrEP promotion campaigns and safe sexual behaviour campaigns among many others.

Comparison: studies will need to have a comparison or control group characterised by the absence of an HIV prevention intervention, having the standard of care routine or having a health intervention whose focus is other than HIV prevention.

Outcome measures: studies reporting findings on outcomes of HIV prevention interventions, for example, condom use, number of sexual partners, incidence of HIV, STI incidence, HIV testing and counselling, uptake of PrEP and PEP, linkage and adherence to ART care, knowledge levels on HIV/AIDS prevention, drug and substance use prior to sexual interactions or other relevant sexual behaviours (sexual activities that may influence infection with HIV among individuals).

Setting: all studies conducted anywhere in the world will be included.

Study designs: interventional studies like randomised control trials (RCTs), quasi-interventional studies and pre-post-test studies will be included.

Exclusion criteria

Non-empirical research studies such as systematic reviews, scoping reviews, literature reviews, meta-analyses and protocols for RCT and quasi-experimental studies will be excluded. Studies reporting on health interventions other than HIV among LDTDs will also be excluded.

Information sources

A comprehensive electronic search will be conducted from PubMed, PubMed Central, Cumulated Index to Nursing and Allied Health Literature, ProQuest Central, EBSCOhost, ScienceDirect, World Health Organisation (Global Index Medicus) and Cochrane Library to identify all relevant published studies. More studies will be manually searched from reference lists of included studies.

Search strategy

A primary search string will be developed from a comprehensive set of key search terms grouped into intervention, condition and population. Synonyms in each search group will be combined using the Boolean operator “OR”. The three search groups will then be combined using the Boolean operator “AND”. This will generate the following primary search string; (“Internet-Based Intervention”[Mesh] OR “Psychosocial Intervention”[Mesh] OR “Implementation Science”[Mesh] OR “Interventions*”[tw] OR “quasi-experimental*” [tw] OR “randomized controlled trial*”[tw] OR “non-randomized interventions” [tw] OR “behaviour change interventions” [tw] OR “risk reduction*”[tw] OR “sexual partner reduction” [tw] OR “peer led education” [tw] OR “SMS campaigns” [tw] OR “community-based campaigns” [tw] OR “educational campaigns” [tw] OR “condom use promotion” [tw] OR “HIV testing*”[tw] OR “sexually transmitted infections screening” [tw] OR “pre-exposure prophylaxis campaigns” [tw] OR “PrEP promotion” [tw]) AND “HIV”[Mesh] OR “Acquired Immunodeficiency Syndrome”[Mesh] OR “Sexually Transmitted Diseases*“[Mesh] OR HIV [tw] OR HIV/AIDS [tw] OR “sexually transmitted infections” [tw] OR “sexually transmitted diseases” [tw] OR STI [tw] OR “venereal diseases” [tw]) AND (“Truck Drivers”[Mesh] OR “long-distance truck drivers”[tw] OR “long-distance truckers” [tw] OR “long-haul truckers” [tw] OR “truck drivers” [tw]). An example of a search syntax used for PubMed which was lastly conducted on 29 April 2024 is given in table 1. The search strategy will be modified to suit the specifications of other databases. Where suitable, Medical Subject Heading (MeSH) terms will be used. Moreover, the reference list of the included studies will be searched to identify potential articles that might meet our eligibility criteria. The search terms will be in English.

Table 1. The search syntax used for PubMed.

Search number	Query	Results
#4	#1 AND #2 AND #3	90
#3	(“Truck Drivers”[Mesh] OR “long-distance truck drivers”[tw] OR “long-distance truckers” [tw] OR “long-haul truckers” [tw] OR “truck drivers” [tw])	1122
#2	(“HIV”[Mesh] OR “Acquired Immunodeficiency Syndrome”[Mesh] OR “Sexually Transmitted Diseases*“[Mesh] OR HIV [tw] OR HIV/AIDS [tw] OR “sexually transmitted infections” [tw] OR “sexually transmitted diseases” [tw] OR STI [tw] OR “venereal diseases” [tw])	559 335
#1	“(Internet-Based Intervention”[Mesh] OR “Psychosocial Intervention”[Mesh] OR “Implementation Science”[Mesh] OR “Interventions*”[tw] OR “quasi-experimental*” [tw] OR “randomized controlled trial*”[tw] OR “non-randomized interventions” [tw] OR “behaviour change interventions” [tw] OR “risk reduction*”[tw] OR “sexual partner reduction” [tw] OR “peer-led education” [tw] OR “SMS campaigns” [tw] OR “community-based campaigns” [tw] OR “educational campaigns” [tw] OR “condom use promotion” [tw] OR “HIV testing*”[tw] OR “sexually transmitted infections screening” [tw] OR “pre-exposure prophylaxis campaigns” [tw] OR “PrEP promotion” [tw])	1 525 555

Meshmedical subject headingPrEPpre-exposure prophylaxisSMSshort message servicetwtext word

Study records

Data management and selection process

The data management and selection process will be done in three stages. The search results will be uploaded in the Rayyan software, an internet-based platform that enables collaboration between reviewers during the screening process.⁴⁶ Initially, duplicate articles will be removed; in the subsequent step, CM and BO will independently screen the titles and abstracts of all records. Any conflicts that arise will be resolved through consensus. Where need be, a third author GM will be consulted. Lastly, retrieved full texts will be assessed for eligibility by both CM and BO. Studies that do not meet eligibility will be listed, as well as the reasons for their exclusion. A PRISMA flow chart will be used to illustrate the entire selection process.⁴⁷

Data collection process

A standard predefined Microsoft Excel data extraction form will be used for data extraction by the two reviewers CM and BO. Initially, the reviewers will pilot the data extraction tool using three studies randomly selected from the included records to assess its suitability. Thereafter, any anomalies identified from the tool will be amended accordingly before the actual data extraction is commenced.

Data items

Where possible, the following variables will be extracted: details of the retrieved articles, study details, intervention characteristics, characteristics of study participants, outcome measures and reported effect size measures. The two reviewers (CM and BO) will later resolve any discrepancies in the extracted data aided by a third author GM where necessary. A detailed summary of the data items to be collected is given in table 2.

Table 2. Data extraction plan.

Category	Variables
Details of the retrieved articles	Title, author and year of publication
Study details	Year the study was conducted, country the study was conducted, study design
Characteristics of study participants	Age, sex and sample size for intervention and control arms for both baseline and postintervention
Intervention characteristics	Name of intervention, setting where the intervention was carried out (community or hospital-based), type of intervention delivery, delivery period/follow-up duration, type of allocation (individual or cluster), type of comparison
Outcome measures	Knowledge of HIV prevention, condom use, risk sexual behaviours, number of sexual partners, HIV testing and counselling, uptake of PrEP, screening and treatment of STIs
Reported effect size measures	Relative risks or risk ratios (RRs), ORs (for dichotomous outcomes) and weighted mean differences or standardised mean differences (for continuous outcomes)

ORodds ratioPrEPpre-exposure prophylaxisRRrelative riskSTIsexually transimitted infection

Outcomes and prioritisation

Given the diverse HIV prevention interventions, it is anticipated that the main outcomes may include but are not limited to knowledge levels on HIV prevention, condom use, sexual partners, HIV testing and counselling, uptake of PrEP and PEP, screening and treatment of STIs, drug and substance use prior to sexual interactions and incidence of HIV and STIs. It is important to note that most of these outcomes are behavioural, except for the incidence of HIV and STIs, and may not always mean a reduction in HIV transmission. These outcomes may be refined to capture others not mentioned here. Where applicable, the preintervention and postintervention outcome measures will be taken into account during data analysis. Absolute numbers, frequencies, percentages and means for specific outcomes will be extracted depending on what is reported in a particular study. The meta-analysis will take into account the difference in means or standardised means where a particular study reports outcomes in the form of a continuous variable. The measures of effect may differ depending on the type of intervention and the targeted outcomes. Therefore, prioritisation for pooled analysis will be based on studies that share similar outcomes. Some of the anticipated measures of effect size include relative risks or risk ratios (RRs) and ORs with 95% CI for dichotomous outcomes. The measure of effect for continuous outcomes will be weighted mean differences or standardised mean differences with 95% CI.

Risk of bias and quality assessment

Two reviewers, CM and BO will independently perform the risk of bias and quality assessment of the included studies. The risk of bias for the randomised control studies will be done using the Cochrane Collaboration tool for assessing the risk of bias in RCTs.⁴⁸ The tool looks into allocation concealment, blinding of study participants, blinding of study assessments and incomplete data among others as possible sources of bias.⁴⁸ For the non-randomised intervention studies, the Joanna Brigs Checklist for non-randomised studies will be used to assess the risk of bias.⁴⁹ The tool assesses for comparisons in the participants involved, the presence of a control group, a multiplicity of measurements (preintervention and postintervention), measurement of outcomes and analysis among other things to assess for bias.⁴⁹ Publication bias will be assessed by inspecting the degree of asymmetry using a funnel plot for the included studies. The quality of evidence in the planned systematic review will be determined by assessing the risk of bias domains like publication bias, precision and consistency of findings in the included studies.

Data synthesis

The general characteristics of the studies will be summarised using descriptive statistics like mean frequencies and SD if they follow a Gaussian distribution or medians and IQR if skewed. The distributions between intervention and control arms will be compared using the χ² test or Fisher’s exact test where appropriate. Where more than two studies report adequate data for an outcome of interest, a random-effects meta-analysis using the ‘metafor’ package in R statistical software⁵⁰ will be done. This is because of the expected heterogeneity between studies and interventions. Similar interventions will be classified together and their pooled effect size estimated and calculated. Where possible, RRs and their 95% CIs will be calculated from the findings of the specific studies to enable the presentation of forest plots during meta-analysis. This will enable an overview of the effect the interventions have had in enhancing HIV prevention outcomes among the LDTDs. Effect sizes will be calculated for studies where they are not provided, using the raw number from intervention arms and control arms. Univariable and multivariable regression will be done using the ‘metareg’ command to assess factors contributing to the variability of effect sizes. Where specific studies may not report adequate data for meta-analysis, their findings will be presented qualitatively.

Given the variations in the methodological approaches of the different studies, study designs, sample sizes and study settings, heterogeneity will be anticipated. Therefore, the researchers will apply a random-effects model to quantify the degree of heterogeneity using the I² statistic, where it is assumed that I² values of 25%, 50% and 75% indicate low, moderate and high heterogeneity, respectively, as the values of I² increase with increasing levels of heterogeneity.^{51 52} Forest plots will be used to visualise the heterogeneity among studies, effect estimates and their CIs. It is anticipated that the studies reporting similar interventions may be few, with their findings being substantially heterogeneous. Therefore, in such a scenario, a subgroup analysis may not be needed. Where possible, a subgroup analysis based on the quality of the studies will be conducted. Publication bias will be assessed and visualised using a funnel plot.

Patient and public involvement

There will be no involvement of patients or the public in the planned systematic review and meta-analysis.

Discussion

This systematic review will describe in detail the HIV prevention interventions targeting LDTDs that have been implemented in various global settings so far. It is anticipated that the review will explore the strengths and weaknesses of individual interventions. Moreover, by assessing the effectiveness of such interventions through a meta-analysis, the study will inform which interventions are most suitable to adopt in resource-limited settings with the potential of yielding better HIV preventive outcomes among LDTDs. This will be instrumental in guiding the formulation of HIV prevention interventions not only for LDTDs but also for other hard-to-reach and at-risk populations.

There are several factors likely to limit this review and meta-analysis. First, given that the searches will be conducted in the English language may mean that some studies written in other languages will be missed. Second, it is anticipated that the studies will be heterogeneous due to varying sample sizes, places of study and study designs. There may also be complexities surrounding the HIV prevention intervention due to varying follow-up durations, nature of interventions and outcomes. As such, it may be hard to have as many individual studies as possible for the pooled analysis. In such a scenario, the reviewers will not be able to get a bigger picture of which interventions are most effective in HIV prevention. Another limiting factor to this review is the fact that only peer-reviewed studies will be included. Whereas this will enhance the quality of data, it will not reduce the risk of publication bias.⁵³ Lastly, it is our wish to conduct the literature searches from as many high-quality databases as possible. However, due to limited resources and the inaccessibility of certain databases which are not open access, such as Excerpta Medica database, we may not use them in this study. This means that some studies that may only be available from such databases are likely to be missed. Nevertheless, the chances of missing any relevant studies are almost negligible, considering that our expanded search involves at least eight databases, behold the recommended minimum of three.

Ethics and dissemination

The systematic review is based on data from already existing peer-reviewed and published studies; therefore, formal ethical approval is not required. The findings will be published in an open-access peer-reviewed journal to reach the larger scientific community. Moreover, the findings will be presented at national and international scientific conferences to reach stakeholders, clinical audiences and policymakers in HIV prevention.