Medical waste disposal practices and their health consequences in resource-limited settings: a systematic review and meta-analysis

Abstract

Background

Safe healthcare waste (HCW) management is critical for environmental and public health. In resource-limited settings (RLS), expanding healthcare services have increased medical waste, but systems for safe disposal are often lacking.

Methods

A comprehensive search of studies published between January 2018 and September 2023 was conducted in PubMed, Scopus, Web of Science, EMBASE, and Global Index Medicus. Included studies were observational studies examining HCW practices and related health outcomes. Two reviewers independently screened studies, assessed quality using Joanna Briggs Institute tools, and extracted data. Meta-analyses were performed using random-effects models to calculate pooled odds ratios (ORs) and prevalence estimates, with heterogeneity quantified using I² statistics.

Results

Of 5,872 records, 94 studies met inclusion criteria. Inadequate waste segregation had a pooled prevalence of 68.4% (95% CI: 61.2–75.1%, I² = 96.5%). Open dumping or uncontrolled burning was the most common disposal method (57.1%, 95% CI: 48.9–65.0%). Healthcare workers in facilities with poor waste management had 4.31 times higher odds of needle-stick injuries (95% CI: 3.02–6.15) and 3.45 times higher odds of Hepatitis B infection (95% CI: 2.10–5.68) compared to controls. Limited community-level data (n = 5, exploratory) showed increased respiratory infections and diarrhea in children living near poorly managed HCW sites.

Conclusion

This study provides comprehensive quantitative evidence that systematic failures in HCW disposal in RLS are directly associated with significant, preventable health risks. The findings underscore an urgent need for targeted interventions including capacity building, resource investment, policy enforcement, and affordable, context-specific technologies to reduce the disease burden linked to unsafe HCW management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-026-26722-9.

Introduction

The global challenge of healthcare waste

Healthcare waste (HCW) is an inevitable byproduct of medical services, generated by hospitals, laboratories, and research institutions. According to the World Health Organization (WHO, 2018) [91], approximately 85% of HCW is non-hazardous and comparable to domestic waste. However, the remaining 15% is hazardous, posing significant risks to human health and the environment. This fraction includes infectious materials (e.g., blood-contaminated items), sharps (e.g., needles, scalpels), pathological waste (e.g., human tissues), chemical and pharmaceutical waste, and radioactive or genotoxic substances [12]. The WHO has also provided guidance for managing such waste in primary care settings [90], though implementation remains inconsistent.

Consequences of inadequate management

Safe HCW management encompassing segregation, collection, treatment, and disposal is essential for protecting public health and the environment. High-income countries typically employ advanced systems such as incinerators, autoclaves, and engineered landfills, governed by strict regulations [84, 92]. In contrast, inadequate waste handling can result in infection transmission, particularly from needle-stick injuries, exposing healthcare workers (HCWs) and waste handlers to HBV, HCV, and HIV [68, 73]. Improper disposal also endangers the public, leading to disease outbreaks and environmental degradation through air, soil, and groundwater pollution [3, 43, 87]. Informal recycling practices, often involving children, further compound these hazards [4, 25]. The health hazards associated with medical waste are well-documented [66], and mismanagement can also undermine circular economy opportunities, especially during public health crises such as the COVID-19 pandemic [79].

The crisis in Resource-Limited settings

Low- and middle-income countries (LMICs), as defined by the World Bank (2022) [93], face acute challenges in HCW management. Rapid population growth, urbanization, and health system expansion have dramatically increased HCW volume [41, 42]. However, chronic underfunding and limited infrastructure such as inadequate segregation tools, non-functional treatment plants, and unsafe disposal sites undermine waste management capacity [2, 10, 16, 22, 30, 35, 37, 49, 50, 56, 61, 62, 70, 72, 77, 85, 95]. These challenges are evident across diverse contexts, from Ethiopia [23, 94] to Iran [36], Bangladesh [69], and India [75]. Moreover, awareness and training among HCWs remain insufficient, and enforcement of existing policies is weak or absent [14, 17, 19, 26, 27, 29, 32, 40, 44, 46, 47, 52, 53, 58, 60, 64, 74, 76, 78, 80, 82, 83, 88].

Rationale and objectives

In many LMICs, unsafe HCW practices such as mixing hazardous and general waste and disposing of waste in open pits or water bodies are common [1, 5–7, 9, 11, 17, 18, 21, 28, 38, 39, 59, 63, 71, 81, 86]. These issues are not limited to clinical waste but extend to broader waste streams, including municipal solid waste [31] and electronic waste [34]. While numerous studies have documented these practices and their health impacts, evidence remains fragmented and lacks quantitative synthesis. This limits the ability of policymakers and development partners to design effective, evidence-based interventions, and the study addresses this gap by providing a systematic review and meta-analysis of HCW disposal practices and associated health outcomes in resource-limited settings.

Objectives

1. To systematically review, synthesize, and identify knowledge gaps in existing evidence on HCW disposal practices in LMICs.

2. To conduct a meta-analysis quantifying the health effects of unsafe disposal methods, including open dumping, burning, and improper segregation.

Methods

Study design and registration

This systematic review and meta-analysis was conducted following the PRISMA 2020 guidelines [65] to ensure methodological rigor, transparency, and reproducibility. The protocol was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD420251246689.

Inclusion criteria

Study eligibility was defined using a PECO framework (Population, Exposure, Comparator, Outcome):

• Population: Healthcare workers (formal and informal), waste handlers, patients, and community members in low- and middle-income countries (LMICs), as classified by the World Bank (2022) [93].

• Exposure: Practices related to medical waste management (collection, segregation, transportation, treatment, and disposal).

• Comparator: Unexposed groups, such as populations distant from waste sites or administrative/non-clinical staff.

• Outcomes:

  • ❖ Primary: Incidence/prevalence of needle stick and sharps injuries (NSIs), seroprevalence of HBV, HCV, and HIV, and prevalence of disposal practices.
  • ❖ Secondary: Environmental contamination, presence of policies/guidelines, and healthcare workers’ Knowledge, Attitude, and Practice (KAP) scores.

Exclusion criteria

We included quantitative, observational studies published in English between January 2018 and September 2023. Studies conducted in high-income countries, editorials, reviews, qualitative research, and case reports were excluded.

Search strategy and information sources

A comprehensive search strategy was developed with a medical librarian. Searches were conducted in PubMed, Scopus, Web of Science, EMBASE, and WHO Global Index Medicus. The search combined MeSH terms and keywords using Boolean operators. Full search strings for each database are provided in Appendix A.

Study selection and data extraction process

References were imported into Covidence for deduplication and screening. The screening, quality assessment, and data extraction were performed by two independent reviewers (A.W.W. and a research assistant, Woinshet Ayantu). Disagreements were resolved through discussion or third reviewer consultation. Inter-rater agreement was assessed using Cohen’s kappa coefficient (Appendix B).

Quality assessment and risk of bias

Two reviewers independently appraised the methodological quality of each study using the Joanna Briggs Institute (JBI) critical appraisal checklists appropriate to the respective study designs [57]. Any discrepancies between reviewers were addressed through a structured and transparent resolution process.

Data synthesis and statistical analysis

Analyses were conducted in R (version 4.3.1) using the ‘meta’ and ‘metafor’ packages.

• Prevalence estimates were pooled using the random-effects model with the DerSimonian–Laird estimator, appropriate given expected heterogeneity.

• Proportions were stabilized using the Freeman–Tukey double arcsine transformation to minimize variance distortion in studies with extreme proportions.

• Dichotomous outcomes were summarized using Mantel-Haenszel odds ratios (ORs) with 95% confidence intervals (CIs) under a random-effects model.

Heterogeneity was quantified using the I² statistic, interpreted as:

• 25% = low,

• 50% = moderate,

• 75% = high.

Pre-specified subgroup analyses were conducted by:

• World Bank region,

• Facility type (hospital vs. primary healthcare facility),

• Study quality.

To address multiple effect sizes from single studies, only the most comprehensive or primary outcome was included unless outcomes were independent. Publication bias was assessed through funnel plots and Egger’s test (for ≥ 10 studies). Criteria for test application followed recommendations from Whiting et al. (2011) [89]. A summary of R code and key functions used is available in Appendix C to support reproducibility.

To enhance transparency in exposure definitions, Table 1 clarifies how key exposures were operationalized across included studies. Where definitions varied, we accepted the original study definitions.

Table 1.

Operational definitions of key exposures across included studies

Exposure	Definition Used in Meta-Analysis	Notes
Inadequate segregation	Failure to separate hazardous waste from non-hazardous at point of generation	Definitions varied; harmonized as reported in original studies
Functional incinerator	On-site incinerator in regular use with emission controls	Based on WHO standards where specified
Open dumping	Waste disposed in non-engineered sites without lining or cover	Consistent across studies

Results

Study selection and characteristics

The systematic database search identified 5,872 records. After removing 1,921 duplicates, 3,951 unique records underwent title and abstract screening. This led to the exclusion of 3,539 records that did not meet the inclusion criteria. The full text of 412 articles was assessed for eligibility, of which 318 were excluded, primarily for wrong population (n = 103), wrong outcome (n = 88), wrong study design (n = 76), or wrong setting (n = 51). Ultimately, 94 studies were included in the qualitative synthesis, with 74 providing sufficient quantitative data for meta-analysis (Table 2; Fig. 1).

Table 2.

Study selection and characteristics

Step	Records (n)	Details
Records identified through database search	5,872	Five electronic databases searched
Duplicates removed	1,921	Remaining: 3,951 unique records
Records screened (title & abstract)	3,951
Records excluded	3,539	Did not meet inclusion criteria
Full-text articles assessed for eligibility	412
Full-text articles excluded	318	Reasons: wrong population (103), wrong outcome (88), wrong study design (76), wrong setting (51)
Studies included in qualitative synthesis	94
Studies included in quantitative synthesis (meta-analysis)	74	Provided sufficient quantitative data

Fig. 1.

The PRISMA 2020 framework for identification of studies via databases and register.

Source: adapted from Page et al., 2021 [65]

Synthesis of waste management practices

The first meta-analysis (n = 74 studies) estimated the prevalence of inadequate segregation. The pooled prevalence was 68.4% (95% CI: 61.2–75.1%), with high heterogeneity (I² = 96.5%, p < 0.01). Due to the high heterogeneity, pooled estimates should be interpreted as indicative of magnitude rather than precise benchmarks. Subgroup analyses showed higher prevalence in primary healthcare facilities (72.1%; 95% CI: 64.3–79.2%) compared to tertiary hospitals (64.5%; 95% CI: 56.1–72.3%), and regional variation with highest prevalence in Sub-Saharan Africa (75.8%; 95% CI: 68.9–81.9%).

A second meta-analysis (n = 58 studies) found uncontrolled open burning was most common (32.5%; 95% CI: 26.1–39.4%), followed by open dumping (24.6%; 95% CI: 19.0–30.8%). Functional incinerators were reported in only 18.3% of cases (95% CI: 13.5–23.8%).

Synthesis of health consequences

Data from 35 studies (22,450 healthcare workers) showed a 12-month prevalence of needle-stick injuries of 42.1% (95% CI: 35.6–48.8%). Healthcare workers in facilities with inadequate waste management had 4.31 times higher odds of NSIs (95% CI: 3.02–6.15; 20 studies). Exposed workers had significantly higher odds of Hepatitis B infection (OR = 3.45, 95% CI: 2.10–5.68; 15 studies). Waste handlers exhibited higher odds of dermatological conditions (OR = 5.12, 95% CI: 2.89–9.07), respiratory disorders (OR = 3.89, 95% CI: 2.45–6.18), and gastrointestinal symptoms (OR = 2.98, 95% CI: 1.85–4.80). Limited community-level studies (n = 5, exploratory) suggested increased prevalence of childhood diarrhoea and respiratory infections near poorly managed HCW sites.

Risk of bias, sensitivity Analyses, and publication bias

Most cross-sectional studies had moderate risk of bias due to non-random sampling or non-validated tools (Table 3). Sensitivity analysis excluding high-risk studies yielded a pooled prevalence of inadequate segregation of 65.1% (95% CI: 57.8–72.0%), confirming robustness of findings. Publication bias was indicated for primary meta-analyses via funnel plot inspection and Egger’s tests (see Supplementary Figures S2 – S3).

Table 3.

Risk of bias summary (Based on JBI Tools)

Study Design	Number of Studies (n)	Low Risk (%)	Moderate Risk (%)	High Risk (%)	Common Sources of Bias
Cross-sectional	71	22 (31.0%)	39 (54.9%)	10 (14.1%)	Non-random sampling, self-reported outcomes, lack of validated instruments
Case-control	12	7 (58.3%)	4 (33.3%)	1 (8.3%)	Recall bias, selection bias
Cohort (prospective or retrospective)	7	5 (71.4%)	2 (28.6%)	0 (0%)	Loss to follow-up, exposure misclassification
Mixed-methods studies	4	1 (25.0%)	2 (50.0%)	1 (25.0%)	Incomplete reporting of quantitative components
Overall Total	94	35 (37.2%)	47 (50.0%)	12 (12.8%)

Discussion

Interpretation of key findings

This systematic review and meta-analysis moves beyond documenting discrete failures to reveal the architecture of a systemic crisis in healthcare waste (HCW) management across resource-limited settings. The synthesis of 94 studies indicates that the high prevalence of inadequate segregation (68.4%) is not merely a procedural failure but a critical breakdown in the first and most fundamental barrier in the waste management hierarchy. This failure initiates a cascade of risk, as the contamination of general waste streams negates the effectiveness of all subsequent handling and treatment processes, effectively multiplying exposure pathways for workers and the environment. The finding that over half (57.1%) of hazardous waste is disposed of via open dumping or burning underscores a reliance on end-of-pipe methods that externalize health and environmental costs, rather than employing integrated, preventive waste management systems. This represents a significant deviation from the precautionary principle central to environmental health.

The quantified health outcomes provide a rare, pooled measure of the human cost of this systemic neglect. The fourfold increase in needle-stick injury risk (OR = 4.31) in facilities with poor practices is not simply a statistic but an indicator of absent or failed engineering and administrative controls. More critically, the elevated odds of Hepatitis B infection (OR = 3.45) among exposed workers highlight a profound policy contradiction: healthcare systems tasked with disease prevention are perpetuating occupational disease through manageable infrastructural and procedural gaps. These findings shift the narrative from one of unfortunate circumstance to one of preventable harm, placing the issue squarely within frameworks of occupational justice and health system accountability.

Contextualization and integration of structural factors with health outcomes

Our results align with but quantitatively strengthen conclusions from regional and narrative reviews. For instance, the pooled prevalence of inadequate segregation (68.4%) and disposal via burning/dumping (57.1%) provides a robust, global estimate that confirms and extends the patterns reported in reviews focused on Africa [13, 95], Asia [41], and the Middle East [48]. Similar patterns of poor segregation and unsafe disposal have been documented in Mauritius [55], Portugal [24], and across healthcare systems in LMICs more broadly [15, 20, 45, 51]. However, this analysis reveals a critical mechanism: the link between upstream segregation failure and downstream health outcomes. While prior studies like those by Windfeld & Brooks (2015) [92] and WHO (2014) [12] outline best practices, our meta-analysis empirically demonstrates the consequence of their absence, showing how poor segregation directly correlates with injury and infection rates.

The high heterogeneity (I² > 96%) in our pooled estimates is itself an informative finding, reflecting not just methodological variation but the profound influence of contextual factors. These include differences in measurement tools, facility types, national regulatory environments, and the presence of informal waste economies. This heterogeneity points to the mechanisms underlying the observed trends: the quality of HCW management is less a function of technical knowledge and more a product of complex interactions between governance (regulation, enforcement), resources (financing, infrastructure), and socio-institutional context (informal waste economies, institutional safety culture). These structural factors directly explain the observed health outcomes: weak governance and inadequate resources lead to poor segregation and unsafe disposal, which in turn cause the high rates of NSIs and infections among workers. Similarly, the preference for open burning, driven by immediate resource constraints, explains the elevated respiratory disorders among waste handlers. The pandemic-related strain noted by Ilyas et al. (2020) [33] exemplifies how external shocks exploit these systemic vulnerabilities, causing managed systems to regress to unsafe practices.

Comparison with conflicting evidence

While our findings are largely consistent with the broader literature, some areas of divergence merit attention. A small number of studies in certain contexts reported lower-than-expected NSI rates or better management practices despite challenging environments. For instance, a study in a National Referral Hospital [47] and a case study of hospitals in a middle-income setting [61] documented more structured waste management and outcomes that contrasted with the broader regional trends captured in our meta-analysis. This divergence may be attributed to several factors: stronger institutional frameworks, dedicated resources, or the advantage of tertiary-level facilities within their respective systems. These examples are critical; they demonstrate that improvement is possible and help isolate the specific institutional and governance factors that can mitigate risk. Conversely, a few studies noted higher community distress near waste sites without clear evidence of clinical infection, highlighting the role of psychosocial and environmental nuisances not captured by our clinical outcomes [67]. These discrepancies underscore the complexity of the issue and suggest that our quantitative estimates, while powerful, may not capture the full spectrum of harm or the potential for localized success. They reinforce the need for mixed-methods approaches and context-specific analyses in future research.

Critical limitations and scientific transparency

The interpretation of these findings must be tempered by several explicit limitations. First, the preponderance of cross-sectional studies fundamentally limits causal inference; while we demonstrate strong associations, the temporal sequence between poor practices and health outcomes is assumed, not proven. Second, the extreme statistical heterogeneity, though explored via subgroup and sensitivity analyses, indicates that our pooled estimates should be interpreted as evidence of a widespread, serious problem rather than a uniform effect size applicable to all settings. This heterogeneity stems from unmeasured variables like local enforcement intensity, the presence of informal recycling sectors, and specific facility-level leadership.

Third, significant measurement bias is likely. Self-reported practices and injuries are vulnerable to recall and social desirability bias, potentially leading to under-reporting of adverse outcomes. Furthermore, publication and language bias may have skewed the evidence base toward larger facilities or English-publishing regions, potentially overlooking locally published successes or failures in harder-to-reach settings. The exclusion of non-English publications may have introduced language bias, potentially limiting representation of evidence from non-English-speaking regions. Finally, the definitional ambiguity of terms like “adequate segregation” across primary studies introduces noise, suggesting an urgent need for standardized, observable metrics in future research.

Fourth, the exclusion of qualitative studies, while methodologically justified for this quantitative synthesis, may underrepresent important contextual factors such as governance barriers, cultural practices, and informal waste sector dynamics. Future research should integrate qualitative evidence to better understand these dimensions.

Expanded implications for Policy, Practice, and future research

The findings compel a move from generic advocacy to targeted, evidence-informed action.

For policy

National governments must integrate HCW management into core health security and universal health coverage agendas, moving it from a facilities management concern to a public health priority. Policy should mandate and fund the separation of waste management budgets from general hospital operations to prevent its relegation as a non-essential cost. Regulations must be specific, enforceable, and apply equally to public and private sectors, with transparency in monitoring and reporting.

For practice and implementation

Investment must shift from solely funding expensive incinerators to supporting a mix of context-appropriate, safer technologies. As suggested by Aung et al. (2019) [8], multi-criteria decision analysis can help select locally feasible solutions. At the facility level, “nudge”-based interventions such as standardized color-coded bin placement and immediate visual feedback on segregation quality can produce significant improvements at low cost. Training must be continuous, practical, and inclusive of all cadres, especially sanitation workers who bear the highest risk.

For future research

To address the causal gap, prospective cohort studies tracking waste handlers and healthcare workers are essential. Implementation science research is critically needed to identify the most effective strategies for changing behavior and sustaining improvements in low-resource facilities. Economic analyses comparing the long-term health costs of unsafe disposal with the upfront investment in safe systems would provide a powerful argument for policymakers. Finally, research must engage with the informal waste sector; a major actor in many settings to develop safer, cooperative models for waste handling and recycling that protect this vulnerable workforce. Such approaches could also align with circular economy principles, particularly in managing plastic waste from healthcare [54].

To sum up, this review synthesizes evidence that transforms the understanding of HCW mismanagement from a series of isolated incidents into a quantifiable, systemic risk factor for disease. The results argue not for incremental change but for a re-framing of safe medical waste management as a non-negotiable component of ethical healthcare delivery, occupational rights, and community health protection in resource-limited settings.

Conclusion

This systematic review and meta-analysis indicate that medical waste management practices in many resource-limited settings remain suboptimal. Common practices such as inadequate segregation, open dumping, and uncontrolled burning were frequently reported and were associated with increased occupational health risks, particularly needle-stick injuries and potential exposure to bloodborne infections. While the evidence consistently highlights risks to healthcare workers, findings regarding broader community and environmental health impacts remain limited and largely exploratory.

Given the predominantly observational design of the included studies, causal inferences should be interpreted with caution. Nevertheless, the findings underscore the need to strengthen healthcare waste management systems through improved policy implementation, workforce training, infrastructure development, and context-appropriate technologies. Coordinated efforts by national authorities, healthcare institutions, and international partners may help enhance occupational safety and environmental protection in resource-constrained settings.

Author contributions

A.W.W. is the corresponding author. He conceived and designed the study, developed the search strategy, performed the database search, conducted the statistical analysis, interpreted all results, and wrote the manuscript. He acted as the lead reviewer in the screening and data extraction process, which was conducted in duplicate with a research assistant, and served as the final arbiter for any discrepancies. The author read and approved the final manuscript.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

All data generated or analyzed during this study are included in this published article and its supplementary information files. Additional details are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

Not applicable. This study is a systematic review and meta-analysis of previously published studies and does not involve direct contact with human subjects or primary data collection.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.