**2. Methods**

Unlike systematic reviews that aim at combining, summarizing, and synthesizing the findings of particular research [30], scoping reviews are conducted for the purpose of mapping the key concepts underpinning a research area, and the main sources and types of evidence that are available [31–33]. Scoping reviews can be undertaken as standalone projects in their own right, especially where an area

is complex or has previously not been reviewed comprehensively [30]. This scoping review was conducted because to our knowledge, no such study has been conducted to explore and map the nomenclature that is used to describe, define, and categorize HCW in HICs and LMICs, in comparison with those provided in the WHO manual for HCW. Both deductive and inductive approaches were applied when conducting this review. First, search terms from the literature were identified. Secondly, the search terms that were identified in the literature were used to search for literature from various databases. Thirdly, the relevant literature was reviewed and selected, and finally, all of the selected literature was mapped.

#### *2.1. Identifying Search Terms*

We used an iterative process to conduct the searches. First, the WHO manual was read in order to derive the first term 'healthcare waste' for the search. The term healthcare waste was used to search and conduct a broad but rapid review of the literature. In order to identify the terms used by ordinary people, policy-makers, and stakeholders, news stories from the 20 newspapers retrieved from the South African print media database were searched. The search was limited to the South African print media, because it was the only available database for news stories within the university at the time of research. The characteristics of the newspapers are summarized in Supplementary Table S1. The various searches yielded the following terms: "healthcare waste", "medical waste", "clinical waste", "biomedical waste", and "hospital waste".

## *2.2. Literature Search*

The initial search was conducted in September 2015 by two student assessors (LH and SM) under the supervision of (OA). Six electronic databases: EBSCOhost, Open Access, ProQuest, PubMed, Web of Science, and Google Scholar were used (see Supplementary Table S2 for the table of all of the databases that were used in the study). These databases were those available at the University of KwaZulu-Natal, Durban, South Africa. We chose both gray and peer-reviewed literature in order to have a broader coverage of the literature. From the initial search, the results were 9735, and too broad. To limit the search, we developed an inclusion criteria to include: (1) only full texts of both grey and peer-reviewed literature that were available through the library at the University of KwaZulu-Natal, (2) literature published from 1990 to 2015, because this period had the highest hits, (3) only English literature, and (4) literature with key search terms in their title and/or their abstracts.

#### *2.3. Review and Selection of Literature*

After applying the inclusion criteria, 8468 studies were excluded, and 1267 remained. Thereafter, the two assessors (LH and SM) worked together to develop a set of explicit exclusion criteria. The exclusion criteria were applied independently by the two assessors, who met regularly to compare the assessments and resolve discrepancies. The criteria were applied as follows. Studies were removed if they: (1) were duplicates and (2) did not define, categorize, and classify HCW in their full texts. After applying the exclusion criteria, 107 duplicates were removed, and 1157 studies remained. A total of 1045 studies that did not define, categorize, or classify HCW in their full text were excluded. The remaining 112 studies (see supplementary table of all included studies Table S3) that met the criteria were mapped as summarized in the PRISMA flow chart in Figure 1.

**Figure 1.** PRISMA flowchart of study selection process.
